TRICKLE-L: 199703XX
is the compilation of discussion during Mar 97
via AB4EL Web Digests @ SunSITE
>From LISTSERV@crcvms.unl.edu Sat Mar 1 09:21:45 1997
Date: Sat, 01 Mar 1997 08:20:30 -0600
Subject: TRICKLE-L Digest - 27 Feb 1997 to 28 Feb 1997
There is one message totalling 24 lines in this issue.
Topics of the day:
1. Peach crop coefficient
Date: Thu, 27 Feb 1997 11:37:46 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Re: Peach crop coefficient
Many thanks for the coefficients, Thomas. Looks like it took some
work to get that out - I really appreciate it!
Bryan
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
End of TRICKLE-L Digest - 27 Feb 1997 to 28 Feb 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Sun Mar 2 01:01:36 1997
Date: Sun, 02 Mar 1997 00:00:18 -0600
Subject: TRICKLE-L Digest - 28 Feb 1997 to 1 Mar 1997
There are 2 messages totalling 53 lines in this issue.
Topics of the day:
1. Alfalfa Production
2. Alfalfa Production under Drip Irrigation
Date: Fri, 28 Feb 1997 18:06:12 -0500
From: Merriott@AOL.COM
Subject: Alfalfa Production
I know there have been some research plots and a lot of sales reps are saying
it can be done, but I would be interested in hearing from any FARMERS who may
be successfully growing alfalfa with buried drip. What kinds of challenges
are you facing (such as gophers, etc.) and how are you dealing with them?
What would you do differently next time?
Randall Merriott
AquaMizer Irrigation
Abernathy, Texas
Date: Sat, 1 Mar 1997 18:52:12 -0800
From: Buck Rogers <brogers@LIGHTSPEED.NET>
Subject: Re: Alfalfa Production under Drip Irrigation
Merriott@AOL.COM wrote:
>
> I know there have been some research plots and a lot of sales reps are saying
> it can be done, but I would be interested in hearing from any FARMERS who may
> be successfully growing alfalfa with buried drip. What kinds of challenges
> are you facing (such as gophers, etc.) and how are you dealing with them?
> What would you do differently next time?
>
> Randall Merriott
> AquaMizer Irrigation
> Abernathy, Texas
Randall Merroitt
Abernathy, Texas
I"ve grown in excess of 3000 acres of Alfalfa in Southern California's
San Joaquin Valley and found it difficult to made Alfalfa pay using
irrigation equipment that is less expensive. I would be very interested
in an opportunity to review the documentation that supports profitable
Alfalfa production using Drip Irrigation. Additionally, I too am
interested in hear anyone experience who is profitable growing Alfalfa
using drip for their irrigation equipment.
Buck
Bakersfield, Califonia
--
GIF89aP
End of TRICKLE-L Digest - 28 Feb 1997 to 1 Mar 1997
***************************************************
>From LISTSERV@crcvms.unl.edu Mon Mar 3 01:04:57 1997
Date: Mon, 03 Mar 1997 00:00:42 -0600
Subject: TRICKLE-L Digest - 1 Mar 1997 to 2 Mar 1997
There are 2 messages totalling 131 lines in this issue.
Topics of the day:
1. Alfalfa Production under Drip Irrigation -Reply
2. Re[2]: Filter selection
Date: Sun, 2 Mar 1997 08:41:54 -0600
From: "Joseph C. Henggeler" <j-henggeler@TAMU.EDU>
Subject: Re: Alfalfa Production under Drip Irrigation -Reply
A reply to Buck Rogers who wrote:
I"ve grown in excess of 3000 acres of Alfalfa ... I would be very
interested... to review the documentation that supports profitable
Alfalfa production using Drip Irrigation. Additionally, ...interested in...
anyone ... who is profitable growing Alfalfa using drip....
Buck
Bakersfield, California
***************
At least one farmer in Texas is making drip alfalfa profitable from the
figures he has reported to the Extension Service. Pertinent data: system
cost $550/acre, short on water, makes about 9.5 tons/acre (field dried
[fd]), sells in small bales for good price. On the other hand, I've seen
some operations that were not profitable.
My observation is that SDI will not make alfalfa production profitable by
merely trimming the cost of water (even with our water costs of $100 per
acre-foot). There probably needs to be an associated yield bump and/or
labor reduction. Yield production increase would probably need to be at
least a ton/acre, if it is to be profitable, and even then there would need to
be some water & labor savings on top of that. There is not a lot of
research data, but there is some, and includes:
1) Brawley, CA; USDA/ARS; clay soil; yield increase over flood of 20%
for shallow tube depths and 26-35% for deep tube depths; approximately
9 tons/ac (fd)
2) Israel; Ben-Gurion Univ; yield increase of 15% over sprinkler;
approximately 11 tons/ac (fd)
3) Hawaii; Hawaiian Sugar Planter's Association; approx same yield as
sprinklers; 11 tons/ac
New Mexico State Univ & Univ of Nevada are beginning studies in SDI
alfalfa and so more data will be available later. Future studies should also
look at some other significant factors that will have a bearing on overall
profitability, but are only anecdotically mentioned now in reports:
stand longevity
earliness
hay quality (differences in weed, protein, etc. content)
Of course, the real proof of whether it works or not is how it performs on
an actual farm. Currently, few such systems are out there..
Joe Henggeler
Date: Mon, 3 Mar 1997 12:14:00 -0500
From: David.Williams@SMTPGWY.AGRIC.NSW.GOV.AU
Subject: Re[2]: Filter selection
Wally,
Thanks for the reply to my question. I have been flat out lately and
am only just starting to catch up again.
DW
______________________________ Reply Separator _________________________________
Subject: Re: Filter selection
Author: Trickle-L Discussion List <TRICKLE-L@crcvms.unl.edu> at smtpgwy
Date: 18/2/97 10:28 AM
At 08:43 AM 13/02/97 -0500, you wrote:
> Hello all,
>
> I have a simple request regarding filter selection.
>
> What are the advantages and disadvantages of both media and screen
> filters in a banked and auto-backflush setup ?
>
> Any opinions would be greatly appreciated. Thanks.
>
> David Williams
> Irrigation Agronomist
> NSW Agriculture
> Yanco NSW 2703
> AUSTRALIA
>
> Ph +61 069 512707
> fax +61 069 557780
>
Dear David
Your Question potentially could require a long - long answer. I'll try and
make it brief.
Media Filters
* Are percieved by many as offering better quality of filtration.
In data from the Platforma trials in Israel (from memory) they showed a
removal of 0.9% of suspended solids, (screen filters removed O.7%).
* Require huge amounts of water for backwashing.
* Take up large space.
* Require additional manifolding, concrete slab, & control.
* Require more maintenance to operate effeciently.
* More expensive.
* More often than not are not maintained adequately by the user.
Screen Filters
* Use considerable less water for backwashing.
* Take-up little space due to compact design, and requires little on-site
preperation.
* Do not require any special manifolding, and can usually be mounted
in the discharge line.
* Usually come with all controls mounted on the unit.
* Less expensive.
* Simple to maintain.
There may be a 100 and 1 other things that others will come up with, but for
many it's really a personal preference and sticking with what they know.
I must admit screen filters have failed on some occasions because they are
usually undersized with inadequate screen surface area
I have been involved with screen filters in drip irrigation for over 13
years, (possible why my answer is bias) to date we have'nt had any
spectacular system failures. (or litigation).
Regards
Wally Menke - Triangle Filtration, Melbourne, Australia
End of TRICKLE-L Digest - 1 Mar 1997 to 2 Mar 1997
**************************************************
>From LISTSERV@crcvms.unl.edu Tue Mar 4 01:02:27 1997
Date: Tue, 04 Mar 1997 00:01:08 -0600
Subject: TRICKLE-L Digest - 2 Mar 1997 to 3 Mar 1997
There are 2 messages totalling 86 lines in this issue.
Topics of the day:
1. Peach crop coefficient -Reply
2. Alfalfa Production under Drip Irrigation -Reply
Date: Mon, 3 Mar 1997 06:14:33 -0800
From: Tom Spofford <tspofford@GW.WCC.NRCS.USDA.GOV>
Subject: Re: Peach crop coefficient -Reply
The USDA - Natural Resources Conservation Service (formally the Soil Conservation Service)
published a manual in 1993 entitled "Irrigation Water Requirements" (Chapter 2 - NEH 15). Page
2-79 contains various coefficients (grass reference) for Peaches on page 2-79. The manual is
available through the Consolidated Forms and Publication Distribution Center, 3222 Hubbard Road,
Landover, Maryland 20785 (USA) by ordering NEH-623-2. Copies are available for viewing at various
NRCS field offices and all State Offices. If anyone is interested in particular crops, I will gladly
e-mail or FAX them the information.
Tom
Thomas L. Spofford, Irrigation Engineer
USDA - Natural Resources Conservation Service
National Water & Climate Center, Water Science & Technology Staff
101 SW Main St., Suite 1600
Portland, OR 97204
PH (503) 414-3075 / FAX (503) 414-3101
e-mail: tspofford@storm.wcc.nrcs.usda.gov
Date: Mon, 3 Mar 1997 20:03:26 -0800
From: Buck Rogers <brogers@LIGHTSPEED.NET>
Subject: Re: Alfalfa Production under Drip Irrigation -Reply
Joseph C. Henggeler wrote:
>
> A reply to Buck Rogers who wrote:
>
> I"ve grown in excess of 3000 acres of Alfalfa ... I would be very
> interested... to review the documentation that supports profitable
> Alfalfa production using Drip Irrigation. Additionally, ...interested in...
> anyone ... who is profitable growing Alfalfa using drip....
>
> Buck
> Bakersfield, California
> ***************
> At least one farmer in Texas is making drip alfalfa profitable from the
> figures he has reported to the Extension Service. Pertinent data: system
> cost $550/acre, short on water, makes about 9.5 tons/acre (field dried
> [fd]), sells in small bales for good price. On the other hand, I've seen
> some operations that were not profitable.
>
> My observation is that SDI will not make alfalfa production profitable by
> merely trimming the cost of water (even with our water costs of $100 per
> acre-foot). There probably needs to be an associated yield bump and/or
> labor reduction. Yield production increase would probably need to be at
> least a ton/acre, if it is to be profitable, and even then there would need to
> be some water & labor savings on top of that. There is not a lot of
> research data, but there is some, and includes:
>
> 1) Brawley, CA; USDA/ARS; clay soil; yield increase over flood of 20%
> for shallow tube depths and 26-35% for deep tube depths; approximately
> 9 tons/ac (fd)
>
> 2) Israel; Ben-Gurion Univ; yield increase of 15% over sprinkler;
> approximately 11 tons/ac (fd)
>
> 3) Hawaii; Hawaiian Sugar Planter's Association; approx same yield as
> sprinklers; 11 tons/ac
>
> New Mexico State Univ & Univ of Nevada are beginning studies in SDI
> alfalfa and so more data will be available later. Future studies should also
> look at some other significant factors that will have a bearing on overall
> profitability, but are only anecdotically mentioned now in reports:
> stand longevity
> earliness
> hay quality (differences in weed, protein, etc. content)
>
> Of course, the real proof of whether it works or not is how it performs on
> an actual farm. Currently, few such systems are out there..
>
> Joe HenggelerJohn
Thank you for the background information.
Buck
--
GIF89aP
End of TRICKLE-L Digest - 2 Mar 1997 to 3 Mar 1997
**************************************************
>From LISTSERV@crcvms.unl.edu Wed Mar 5 01:03:10 1997
Date: Wed, 05 Mar 1997 00:01:55 -0600
Subject: TRICKLE-L Digest - 3 Mar 1997 to 4 Mar 1997
There are 5 messages totalling 205 lines in this issue.
Topics of the day:
1. 1997 Designer Manager School of Irrigation
2. Peach crop coefficient
3. Peach crop coefficient - Thanks!
4. Crop coefficient WWW location
5. Filtering pond water
Date: Tue, 4 Mar 1997 09:41:22 -0800
From: spiplow <spiplow@POLYMAIL.CPUNIX.CALPOLY.EDU>
Subject: 1997 Designer Manager School of Irrigation
The Irrigation Training and Research Center (ITRC) is offering 12 classes
during its 1997 Designer/Manager School of Irrigation, sponsored by the
U.S. Bureau of Reclamation. The Designer/Manager School is a
comprehensive educational program offering a variety of classes designed
for both agricultural and landscape irrigation professionals. The classes
vary in length from one to three days and all take place at ITRC facilities
at California Polytechnic State University, San Luis Obispo. To register
for any of the classes or for more information you may contact Susanne
Piplow at (805) 756-2434, or by e-mail at
spiplow@rubens.artisan.calpoly.edu. These classes have been well attended
in the past and tend to fill quickly so register early.
Following is a list and brief description of each class:
BASIC SOIL, PLANT & WATER RELATIONSHIPS (July 28, Monday; $150)
Suggested Prerequisites: None
Covers IA Level II material on this topic; Texture and structure; Water
holding capacity, retention; Intake rates; Evaporation; Transpiration;
Soils classification; Measurement of soil moisture and tension.
BASIC PIPELINE HYDRAULICS (July 29, Tuesday; $120)
Suggested Prerequisites: None
Pipe materials & sizes; Mainline computations, tapered pipe, branches;
Energy equation, friction, elevation changes; Minor losses.
BASIC PUMPS (July 30, Wednesday; $150)
Suggested Prerequisites: None
Pump curves; Pumps in series and parallel; System curves; TDH computations
for vertical and booster pumps; Efficiency, WHP, BHP, input HP; Pump
selection from catalogs.
CHEMIGATION (July 31, Thursday; $120)
Sug. Prereq.: None PCA Credit: 5.1 hours
Fertilizers; Techniques for various irrigation methods; Reducing leaching
losses; Emphasis on drip/micro;Injection equipment and safety.
ADVANCED PUMPS (July 31 - Aug. 1, Thursday - Friday; $250)
Suggested Prerequisite: Basic Pipeline Hydraulics, Basic Pumps
NPSH; Submersible pumps; Well screens and well development; Variable
speeds; electric and engine; Shaft losses, shaft sizing; Maintenance and
trouble-shooting.
ROW CROP DRIP IRRIGATION (August 1, Friday; $120)
Suggested Prerequisite: Basic Pipeline Hydraulics
Design layouts, flushing, fittings; How design relates to management; Hose
installation, retrieval.
DRIP/MICROIRRIGATION (August 4 - 6, Monday - Wednesday; $360)
Suggested Prerequisite: Basic Soil, Plant & Water Relationships, Basic
Pipeline Hydraulics, Basic Pumps
Filtration; Step-by-step design procedure of hardware selection &
hydraulics; Emitter and micro system designs; Buried drip for trees and
vines; Plugging prevention.
IRRIGATION SCHEDULING, SALINITY & DRAINAGE (August 7 - 8, Thursday &
Friday; $240)
Suggested Prerequisite: Basic Soil, Plant & Water Relationships
ETo and crop coefficients; Practical irrigaion scheduling; How efficiency
and uniformity influence scheduling; Drainage concepts and layouts;
Salinity; Leaching requirements, reclamation.
LANSCAPE IRRIGATION AUDITOR (August 4 - 5, Monday &Tuesday, $235)
Suggested Prerequisite: None PCA Credit: 16 hours
Software included; Irrigation evaluation and irrigation scheduling;
Sprinklers, drip, micro, and bubbler.
WATER BUDGETING FOR LANDSCAPE (August 6, Wednesday; $95)
Suggested Prerequisite: None
Includes ITRC's latest software; Design and/or manage a site to a water
budget; Allows users to conform to AB 325, Model Landscape Ordinance.
LANDSCAPE SPRINKLER DESIGN (August 7, Thursday; $150)
Suggested Prerequisite: Basic Soil, Plant & Water Relationships, Basic
Pipeline Hydraulics
Application rates; Valves, piping, pipeline sizing; Sprinkler selections,
designing blocks.
MICROIRRIGATION FOR LANDSCAPE (August 8, Friday; $150)
Suggested Prerequisite: None
Hydraulics of hoses, emitters, and sprayers; Equipment selection and
maintenance of the system; How to match equipment to plant materials and
other stations.
Susanne Piplow, Program Assistant
Irrigation Training and Research Center (ITRC)
BioResource and Agricultural Engineering Dept.
California Polytechnic State University
San Luis Obispo, CA 93407
ph: 805-756-2434
FAX: 805-756-2433
e-mail: spiplow@.rubens.artisan.calpoly.edu
Date: Tue, 4 Mar 1997 13:22:45 -0500
From: LRP@ICON.LAL.UFL.EDU
Subject: Re: Peach crop coefficient
To M. Meron, I'm interested in the pan coefficients that you mentioned
that were developed by the Soil & Extension Service in Israel. How can
one get these? Can they be obtained in the U.S?
Larry Parsons University of Florida
Date: Mon, 3 Mar 1997 14:40:08 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Peach crop coefficient - Thanks!
I would like to thank everyone responding to my request concerning
Peach coefficients. The information I received was exactly what I
needed (and yes, Freddie and Joe, I did purchase the proceedings of
the ASAE ET and Scheduling conference in San Antonio and have
found them to be very useful!).
Also many thanks to those providing information on delaying bloom
set with sprinklers / microsprinklers. A special thanks to Ken
Montgomery for the bloom delay paper sent via snail-mail.
Bryan
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
Date: Tue, 4 Mar 1997 09:18:42 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Crop coefficient WWW location
With the recent information on crop coefficients in mind, here's
a web site I found (with help from Dr. Dale Linvill, Clemson
University) at Texas A&M. It lists FAO crop coefficients
and some for the Texas area:
http://agen.tamu.edu/wqit/pet/pet_tool/crop-tool.html
Bryan
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
Date: Sun, 2 Mar 1997 19:14:03 -0800
From: John Klueh <kleeford@PSCI.NET>
Subject: Filtering pond water
I have checked with several sources about filtering equipment for drip =
systems using surface water as a source. In my case we are using pond wat=
er. Some sources say sand media filters are an absolute necessity, while =
others suggest disk filters may be adequate. Is there are consensus on =
this issue? Does it depend upon other factors? Thanks in advance to all =
respondents.
=
John Klueh kleeford@psci.net
End of TRICKLE-L Digest - 3 Mar 1997 to 4 Mar 1997
**************************************************
>From LISTSERV@crcvms.unl.edu Thu Mar 6 10:37:09 1997
Date: Thu, 06 Mar 1997 00:00:47 -0600
Subject: TRICKLE-L Digest - 4 Mar 1997 to 5 Mar 1997
There are 2 messages totalling 104 lines in this issue.
Topics of the day:
1. Trickle-L update
2. Trickle-L archive update
Date: Mon, 3 Mar 1997 18:17:27 +0000
From: Richard Mead <rmead@CYBERGATE.COM>
Subject: Trickle-L update
The January 1997 Trickle-L archives have been compiled for the "Best of"
section of the Microirrigation Forum (www.cybergate.com/~rmead).
Topics discussed include:
-Controller to monitor pH and EC
-Delaying Bloom set with microsprinklers
-Disposal of wastewater: Where to place SDI?
-Drip irrigation of mature trees
-Organic fertilizers for SDI ?
-SDI on Corn ?
-SDI and weed growth
-Watermarks hooked to datalogers
The list of topics under the "Best of" section is growing. Soon, I will
place all the topics into certain categories so that it will be easier to
find information. The categories I propose to create are:
-Chemical use
-Cultural Practices
-Effects on crops
-Engineering
-Landscaping
-SDI (subsurface drip irrigation)
-Soil moisture instrumentation
-New ideas
-Water problems
-Related information tables
Please check out the URL http://www.cybergate.com/~rmead/best.html to see
if there should be other categories for the "Best of" section of the
Microirrigation Forum. I'm open for any suggestions.
Finally, I recently read an article in the Jan/Feb '97 issue of the
Irrigation Journal regarding a vineyard manager using a product called
"Sure Flow" for water treatment. The article was not detailed enough to
explain what "Sure Flow" is or how it worked. Does anyone on this list have
any idea (without going into a sales pitch) of what this product is and how
it works. I have an hunch it is something like N-Phuric (combination of
sulfuric and Urea made by UnoCal), but I could be proven wrong.
Richard Mead
Trickle-L & Microirrigation Forum manager
Date: Tue, 4 Mar 1997 15:59:54 +0000
From: Richard Mead <rmead@CYBERGATE.COM>
Subject: Trickle-L archive update
The January '97 Trickle-L archives have been compiled for the "Best of"
section of the Microirrigation Forum (www.cybergate.com/~rmead).
Topics discussed include:
-Controller to monitor pH and EC
-Delaying Bloom set with microsprinklers
-Disposal of wastewater: Where to place SDI?
-Drip irrigation of mature trees
-Organic fertilizers for SDI ?
-SDI on Corn ?
-SDI and weed growth
-Watermarks hooked to datalogers
The list of topics under the "Best of" section is growing. Soon, I will
place all the topics into certain categories so that it will be easier to
find information. The categories I propose to create will be:
-Chemical use
-Cultural Practices
-Effects on crops
-Engineering
-Landscaping
-SDI (subsurface drip irrigation)
-Soil moisture instrumentation
-New ideas
-Water problems
-Related information tables
Please check out the URL http://www.cybergate.com/~rmead/best.html to see
if there should be other categories for the "Best of" section of the
Microirrigation Forum. I'm open to all suggestions.
Finally, I recently read an article in the Jan/Feb '97 issue of the
Irrigation Journal regarding a vineyard manager using a product called
"Sure Flow" for water treatment. The article was not detailed enough to
explain what "Sure Flow" is or how it worked. Does anyone on this list have
any idea (without going into a sales pitch) of what this product is and how
it works. I have an hunch it is something like N-Phuric (combination of
sulfuric and Urea made by UnoCal), but I could be proven wrong.
Richard Mead
Trickle-L & Microirrigation Forum manager
End of TRICKLE-L Digest - 4 Mar 1997 to 5 Mar 1997
**************************************************
>From LISTSERV@crcvms.unl.edu Fri Mar 7 01:04:31 1997
Date: Fri, 07 Mar 1997 00:03:03 -0600
Subject: TRICKLE-L Digest - 5 Mar 1997 to 6 Mar 1997
There is one message totalling 66 lines in this issue.
Topics of the day:
1. Filtering pond water
Date: Wed, 5 Mar 1997 16:29:28 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Re: Filtering pond water
John,
Here's my two cents' worth based on my experiences:
Screen, disk, and sand media filters can provide the same level of
filtration. BUT, sand media filters generally have a much larger
filtration area, so require cleaning less often.
Given you are using surface water, I would not hesitate to use a
properly-sized sand media filter. If this water is clean (read very
clear), you might consider a disk or screen filter. I would heartily
recommend an automated backflush (cleaning) system for the media
filters - it will save you lots of time and heartache. Also, if you
plan to use a screen or disk filter, I would go so far as to suggest
that the automated backflush is a *requirement* due to increased
frequency of cleanings required.
Back-flushing a media filter is supposed to lift the sand bed
slightly, which should (opinion here) loosen the sand particles and
thereby allow dirt particles to be flushed out more effectively than
back-flushing a screen or disk filter. ( I would appreciate comments
on this opinion!)
Pros and cons:
Screen/disk filters
- easy to disassemble, clean, and reassemble
- no replacement screens needed (barring physical damage)
- very frequent cleanings required (one grower reported every
30 - 40 minutes with a 200 mesh screen filter, which sub-
sequently dropped to every 3 hours with a 150 mesh screen filter)
Media filters
- infrequent cleanings required
- probable higher inital cost
- requires changing of filter sand every 1 or 2 years
Finally, you might consider injecting chlorine before the filter.
This will prevent algae growth and subsequent problems in the media
filter (it can form a slimy mat in the upper layer of the sand over a
period of time and raise the pressure loss in the filter
significantly).
Hope this gets you started!
Bryan
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
End of TRICKLE-L Digest - 5 Mar 1997 to 6 Mar 1997
**************************************************
>From LISTSERV@crcvms.unl.edu Sat Mar 8 09:41:18 1997
Date: Sat, 08 Mar 1997 08:40:18 -0600
Subject: TRICKLE-L Digest - 6 Mar 1997 to 7 Mar 1997
There is one message totalling 34 lines in this issue.
Topics of the day:
1. Filtering pond water
Date: Fri, 7 Mar 1997 15:13:42 +0000
From: Blake Sanden <blsanden@UCDAVIS.EDU>
Subject: Re: Filtering pond water
John,
If the pond water has a settling time of 12+ hours you may be able to get
away with a rotating inlet 60-80 mesh screen filter submerged in the pond.
These are made by Plum Creek and use a little pump pressure to discharge
water through T-jet nozzles aimed at the large screen cylinder to keep it
rotating and free of algae. Sorry, I don't have a phone number. I'm sure
that one of the Tricklers out there does.
Blake Sanden
Irrigation Management & Agronomy Farm Advisor, Kern County
1031 S Mt Vernon Ave
Bakersfield, CA 92307
805-868-6218
blsanden@ucdavis.edu
>I have checked with several sources about filtering equipment for drip
>systems using surface water as a source. In my case we are using pond
>water. Some sources say sand media filters are an absolute necessity,
>while others suggest disk filters may be adequate. Is there are consensus
>on this issue? Does it depend upon other factors? Thanks in advance to all
>respondents.
>
>
>John Klueh kleeford@psci.net
End of TRICKLE-L Digest - 6 Mar 1997 to 7 Mar 1997
**************************************************
>From LISTSERV@crcvms.unl.edu Mon Mar 10 01:02:01 1997
Date: Mon, 10 Mar 1997 00:01:03 -0600
Subject: TRICKLE-L Digest - 7 Mar 1997 to 9 Mar 1997
There is one message totalling 29 lines in this issue.
Topics of the day:
1. Trickle-L update
Date: Sun, 9 Mar 1997 09:04:31 -0800
From: Steve Jordan <sjordan@UTECH.NET>
Subject: Re: Trickle-L update
>Finally, I recently read an article in the Jan/Feb '97 issue of the
>Irrigation Journal regarding a vineyard manager using a product called
>"Sure Flow" for water treatment. The article was not detailed enough to
>explain what "Sure Flow" is or how it worked. Does anyone on this list have
>any idea (without going into a sales pitch) of what this product is and how
>it works. I have an hunch it is something like N-Phuric (combination of
>sulfuric and Urea made by UnoCal), but I could be proven wrong.
>
I use Sure Flow. It provides the same type of function as does N-Phuric.
It prevents scale and precipitate buildup.
N-phuric lowers the pH, which lowers the risk of calcium carbonate buildup.
It adds N at the same time. Some believe a lowered water pH has crop
benefits in some cases.
Sure Flow is a "magic" chemical. I forget whether it is a PolyMoleyic Acid
or a phosphonate. I think it is a phosphonate. It keeps the calcium and
iron (!) in solution. It works in parts per million.
Steve Jordan- Artichoke Evangelist, Wetland manager
End of TRICKLE-L Digest - 7 Mar 1997 to 9 Mar 1997
**************************************************
>From LISTSERV@crcvms.unl.edu Fri Mar 14 01:03:04 1997
Date: Fri, 14 Mar 1997 00:02:03 -0600
Subject: TRICKLE-L Digest - 9 Mar 1997 to 13 Mar 1997
There are 2 messages totalling 34 lines in this issue.
Topics of the day:
1. No messages (2)
Date: Thu, 13 Mar 1997 08:25:30 -0300
From: andokoltex@GIGA.COM.AR
Subject: No messages
I have not received any message in the last four days. Is there any
problem with the service?
Mario A. SANCHEZ
-----------------------------------------
Laboratorio Industrial Ando Koltex S.A.
Buenos Aires, ARGENTINA
andokoltex@giga.com.ar
-----------------------------------------
to: IN:TRICKLE-L@crcvms.unl.edu
cc: in:marito@siscor.bibnal.edu.ar
in:msanchez@giga.com.ar
in:andokoltex@giga.com.ar
Date: Thu, 13 Mar 1997 10:38:32 -0800
From: Robert Carian <grapegrower@EARTHLINK.NET>
Subject: Re: No messages
>I have not received any message in the last four days. Is there any
>problem with the service?
we are out of water
End of TRICKLE-L Digest - 9 Mar 1997 to 13 Mar 1997
***************************************************
>From LISTSERV@crcvms.unl.edu Sat Mar 15 16:19:55 1997
Date: Sat, 15 Mar 1997 10:19:54 -0600
Subject: TRICKLE-L Digest - 13 Mar 1997 to 14 Mar 1997
There are 4 messages totalling 131 lines in this issue.
Topics of the day:
1. No messages (3)
2. Pump system reference books?
Date: Fri, 14 Mar 1997 09:47:33 -0800
From: Jochen Eberhard <Jochen.Eberhard@T-ONLINE.DE>
Subject: Re: No messages
Robert Carian wrote:
>
> >I have not received any message in the last four days. Is there any
> >problem with the service?
> we are out of water
Hi,
no problem at all. I do have a question as I do not have a problem to
think of stupid questions :-)
The emitter spacing of drip tapes. What are the pros and contras for
closer and wider emitter spacing respectively?
A few years ago the price per meter tape increased with closer emitter
spacing. Today there is almost no difference at all.
But with closer emitter spacing the head loss in long laterals is higher
than with wider emitter spacing.
Some other agruments: more homogenous soil wettening even with some
clogged emitters with closer emitter spacing, and with that in mind
better irrigation management with tensiometers.
Is there any differenc with surface and subsurface drip.
What do you think, is it better to use drip tape with closer emitter
spacing?
I am looking forward to any comment
Jochen Eberhard, Germany
--
_____________________________________________________________
| Jochen Eberhard * * |
| SLFA Versuchsbetriebe ( \ / ) |
| Queckbrunnerhof \ / |
| Dannstadter Str. 91 --- |
| 67105 Schifferstadt (o|o) |
| Germany ( ~~~ ) |
| ( ) |
| Tel: 0049 - 6235 - 2672 ( ) |
| Fax: - - 82741 ( ooO Ooo ) |
| email: Jochen.Eberhard@t-online.de |
|_____________________________________________________________|
Date: Wed, 12 Mar 1997 20:59:58 -0800
From: John Klueh <kleeford@PSCI.NET>
Subject: Pump system reference books?
Thanks to all who responded regarding filtering. I am particularly intere=
sted in the Amiad self-flushing filter. I talked with a representative =
today who is sending me more info. He did mention that they are more effe=
ctive filtering non-organic solids, and less effective when filtering alg=
ae and other organic materials.
Are there any good, non-technical (i.e. for the grower/applicator) refere=
nces and/or catalogs that go into some detail about pumps and pump set-up=
, and again I am particularly interested in surface water setup, not well=
pumping. Thanks.
John Klueh =
kleeford@psci.net
Date: Thu, 13 Mar 1997 10:56:38 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Re: No messages
Neither have I, Mario. Everyone must be either content, having no
problems, or working hard ....! : )
Bryan
> I have not received any message in the last four days. Is there any
> problem with the service?
>
> Mario A. SANCHEZ
>
> -----------------------------------------
> Laboratorio Industrial Ando Koltex S.A.
> Buenos Aires, ARGENTINA
> andokoltex@giga.com.ar
> -----------------------------------------
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
Date: Fri, 14 Mar 1997 18:44:39 -0800
From: Rodney Ruskin <geoflow1@SLIP.NET>
Subject: Re: No messages
At 09:47 AM 3/14/97 -0800, Jochen Eberhard wrote:
>Robert Carian wrote:
>>
>The emitter spacing of drip tapes. What are the pros and contras for
>closer and wider emitter spacing respectively?
REPLY
The work of Phene et. al. clearly indicates that with deep pulsed SDI the
lateral spread is less than for surface drip. However the wetted volume and
wetted surface is much higher - therefor closer spacing
Rodney
geoflow1@slip.net
End of TRICKLE-L Digest - 13 Mar 1997 to 14 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Sun Mar 16 08:50:53 1997
Date: Sun, 16 Mar 1997 00:00:41 -0600
Subject: TRICKLE-L Digest - 14 Mar 1997 to 15 Mar 1997
There is one message totalling 9 lines in this issue.
Topics of the day:
1. Pump system reference books?
Date: Sat, 15 Mar 1997 10:28:04 -0500
From: Tim1Utah@AOL.COM
Subject: Re: Pump system reference books?
Are you looking for sizing and design info or installation info, in regards
to pumps?
End of TRICKLE-L Digest - 14 Mar 1997 to 15 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Tue Mar 18 12:45:47 1997
Date: Tue, 18 Mar 1997 00:01:09 -0600
Subject: TRICKLE-L Digest - 15 Mar 1997 to 17 Mar 1997
There are 4 messages totalling 99 lines in this issue.
Topics of the day:
1. Pump system reference books? (2)
2. EMITTER SPACING
3. TRICKLE-L Digest - 14 Mar 1997 to 15 Mar 1997
Date: Sun, 16 Mar 1997 10:28:41 -0800
From: John Klueh <kleeford@PSCI.NET>
Subject: Re: Pump system reference books?
----------
>
> Are you looking for sizing and design info or installation info, in reg=
ards
> to pumps?
I am particularly interested in installation info for surface water pumpi=
ng. But also would be interested in sizing and design info, as long as =
it wasn't too technical. Any recommendations for reference books and/or =
catalogs? Thanks.
Date: Mon, 17 Mar 1997 08:35:18 -0600
From: Louis Baumhardt <r-baumhardt@TAMU.EDU>
Subject: EMITTER SPACING
I am very interested in pulse SDI affects on soil wetting paterns;
but I haven't found much in the way of Journal articles on the topic.
Rodney Ruskin's reply on emitter spacing promises some light in this
area:
>>>>>>>>>>>>>>>>>>>>>>
Date: Fri, 14 Mar 1997 18:44:39 -0800
From: Rodney Ruskin <geoflow1@SLIP.NET>
Subject: Re: No messages
REPLY
The work of Phene et. al. clearly indicates that with deep pulsed SDI
the
lateral spread is less than for surface drip. However the wetted
volume and
wetted surface is much higher - therefor closer spacing
Rodney
geoflow1@slip.net
<<<<<<<<<<<<<<<<<<<<<<<
PLEASE provide citations of articles written by "Phene et al." on his
deep pulsed SDI - wetting pattern work.
Thanks.
R. Louis Baumhardt, Res. Assoc.
Texas Agric. Exp. Station
Rt. 3 Box 219
Lubbock, TX 79401-9757
806-746-6528 FAX
806-746-6101 Voice
r-baumhardt@tamu.edu
Date: Sun, 16 Mar 1997 09:31:53 -0800
From: John Stewart <jdstewart@KANSERVU.CA>
Subject: Re: TRICKLE-L Digest - 14 Mar 1997 to 15 Mar 1997
Automatic digest processor wrote:
>
> Subject: Re: Pump system reference books?
>
Goulds has a very good industrial catalog, the GPM, and a water systems
catalog as well. You might try looking at the Goulds G&L line as it is
the least expensive way to get a stainless steel pump (if you need one).
Look in the phone book for Goulds distributors.
Best regards,
John Stewart
Date: Mon, 17 Mar 1997 16:03:50 -0500
From: Tim1Utah@AOL.COM
Subject: Re: Pump system reference books?
The IA has a very good manual for sizing and specifing pumps. It is written
in lay terminalogy as well. "Understanding Pumps" Look at our Web site
http://www.irrigation.org or call 703-573-3551. Tim Wilson
End of TRICKLE-L Digest - 15 Mar 1997 to 17 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Wed Mar 19 01:03:37 1997
Date: Wed, 19 Mar 1997 00:02:07 -0600
Subject: TRICKLE-L Digest - 17 Mar 1997 to 18 Mar 1997
There are 7 messages totalling 314 lines in this issue.
Topics of the day:
1. emitter spacing
2. Pump system reference books? (2)
3. Citrus List Server
4. Pump System/ New Technology/ Yet to Appear in Reference Books (2)
5. Irrigation controllers
Date: Tue, 18 Mar 1997 13:54:42 -0800
From: Jochen Eberhard <Jochen.Eberhard@T-ONLINE.DE>
Subject: Re: emitter spacing
Hi everybody,
>
> thank you very much for the excellent comments on my question on emitter
> spacing.
> If I understood it right, the best is to keep the Q100 constant as low
> as possible. So with a closer emitter spacing the emitter flow rate will
> be lower than with wider emitter spacing but the friction loss will be
> the same. Higher emitter rates are better to prevent plugging. So with
> contaminated water it is important to have a high emitter flow rate.
> This can be obtained with a wider emitter spacing and/or a high Q100. A
> higher Q100 means a high water pressure which results in a higher
> pressure head loss and therefore in a worse distribution uniformity.
>
> So the way to decide which emitter spacing would be best, one fist has
> to decide the minimum emitter flow rate to prevent plugging. Second the
> length of the field and third the manufactor catalouge which tells you
> the Q100 and the DU for a specific tape.
> I have just found a computer program from a drip tape company which does
> the same automatically, but just the other way round, by selecting a
> specific tape first.
>
> So I see to parties being in contrast to one another. First the task to
> prevent plugging which tends to use wider emitter spacing to get higher
> emitter flow rates and second the soil and plants which like closer
> emitter spacings to get a more uniform wetted soil. The optimal emitter
> spacing therefore will always be a compromise between this two factors
> and has to be adapted to the specific situation.
> And there is basically no difference between surface and subsurface drip
> irrigation
>
> Thanks again for helping me to see things clear.
> Jochen
>
> _____________________________________________________________
> | Jochen Eberhard * * |
> | SLFA Versuchsbetriebe ( \ / ) |
> | Queckbrunnerhof \ / |
> | Dannstadter Str. 91 --- |
> | 67105 Schifferstadt (o|o) |
> | Germany ( ~~~ ) |
> | ( ) |
> | Tel: 0049 - 6235 - 2672 ( ) |
> | Fax: - - 82741 ( ooO Ooo ) |
> | email: Jochen.Eberhard@t-online.de |
> |_____________________________________________________________|
Date: Mon, 17 Mar 1997 08:36:08 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Re: Pump system reference books?
>
> Are there any good, non-technical (i.e. for the grower/applicator) references and/or catalogs that go into some detail about pumps and pump set-up, and again I am particularly interested in surface
> ater setup, not well pumping. Thanks.
>
> John Klueh kleeford@psci.net
John,
Berkeley has a fairly good, non-rechnical book out titled "Berkeley
Care Manual," number B1521. Berkeley is now a part of Sta-Rite
Industries - try calling them at
800-241-4144
or writing at
Berkeley Pump
293 Wright Street
Delavan, Wisconsin, USA 53115
The book has some good, non-technical labelled pictures and
diagrams on pump installation, start-up, maintenance, and general
pump nomenclature. A good book to start with - even covers flooded
and non-flooded suctions, discharge assemblies, shaft alignment, pump
foundation, and priming.
I hope this is what you need.
Bryan
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
Date: Mon, 17 Mar 1997 08:12:14 -0600
From: Rick Simpson <bcsl@POBOX.COM>
Subject: Citrus List Server
Dear Trikle-L Server Participants:
This note to let any citrus growers and others interested in citrus
production know that there is a new Citrus List Server
now established to provide a forum for matters related to citrus
production, its problems and solutions. To subscribe, send email
message to:
citrus-request@psg.com
You may leave the subject line blank.
In the text of the message, send the word
subscribe
Hope this information may be helpful to citrus related interests.
Rick Simpson
bcsl@pobox.com
Date: Mon, 17 Mar 1997 10:23:15 -0500
From: "Craig A. Storlie" <storlie@AESOP.RUTGERS.EDU>
Subject: Re: Pump system reference books?
------ =_NextPart_000_01BC3387.ECE28140
John:
Be certain to keep the suction inlet in your pond/stream off the =
surface and off the bottom. Surface waters are used extensively in the =
northeast and so are sand media filters. Your rep was absolutely right =
- high concentrations of algae and higher aquatic types can challange a =
self-cleaning disk filter.
Craig Storlie
Rutgers University
------ =_NextPart_000_01BC3387.ECE28140
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AAAFAAAAUkU6IAAAAAAJ0w==
------ =_NextPart_000_01BC3387.ECE28140--
Date: Tue, 18 Mar 1997 10:34:13 -0800
From: Clem Wehner <cww@PACIFICCOAST.NET>
Subject: Re: Pump System/ New Technology/ Yet to Appear in Reference Books
For John Klueh,
At 08:59 PM 3/12/97 -0800, you wrote:
>Are there any good, non-technical (i.e. for the grower/applicator)
>references and/or catalogs that go into some detail about pumps and
>pump set-up, and again I am particularly interested in surface water
>setup, not well pumping. Thanks.
John Klueh
kleeford@psci.net
--------------------------- 0 -----------------------
There is a new surface water pump set-up for which I have been asked to do
a survey among irrigators to determine if there is interest in this new
technology and how it would adapt to their individual needs.
The pump set-up floats in a pond or other open reservoir and pumps
water ashore. (Its development and testing was done in an abandoned
gravel pit full of water suitable for irrigating row crops).
The pump is wind-powered by a unique single-wing arrangement. A breeze
of 3 knots or 1.5 meters per second is enough to cause pumping to start.
At about 8 knots or 4 meters per second, for example, the system delivers
a gallon of water per second at about 8 feet of head.
The to-and-fro oscilating motion of the surface-mounted wing is transmitted
by a floating pendulum and rocker beams to submerged pumps. Two, piston-
-in-cylinder pumps reciprocate to push water into a crosspipe then to
shore. An air reservoir in the underwater crosspipe cushions pressure
from the pump cylinders while new water flooding in from source through
a foot valve pushes the pump pistons up, refills the cylinders, ready
for the next wind-driven push.
One person, working from shore, can set up and maintain a
Floating Flutter Pressure Pump. The above-water wing and
mechanisms can withstand gale-force winds. As high velocity
winds increase, wing and rocker motion self-protectively decrease.
The below-water pumps and pipes are mounted on a swivel, this
allows them to follow wind direction without entangling or twisting
anchor lines or the pipe carrying water to shore.
The above description of the surface water pump set-up can be
appreciated more clearly by photograph or video or both. If
you have an E-mail server such as Eudora with MIME you can receive
a photo attached to an e-mail message, save it to disk, then view
it with a Web browser such as Netscape. Or you can ask for a video
for viewing via a VCR, narration in either English or Spanish.
There is available a well-mounted version of the wing'd pump.
Also, it can be adapted to aerate reservoirs.
Yours truly,
Clem Wehner C. Wehner & Associates
Marketing Consultants Internional
905 Gordon Street
Victoria, B.C. V8W 3P9
Phone and Fax: 800-881-0704 Toll Free
" " " 250-383-1959
E-mail: cww@pacificcoast.net
-------------------------- 0 --------------------------
Date: Tue, 18 Mar 1997 14:09:50 -0800
From: Richard Mead <rmead@CYBERGATE.COM>
Subject: Irrigation controllers
There has been some discussion in the recent past about irrigation
controllers. There is an article in the online version of "Landscape and
Irrigation" magazine which discusses this issue in some detail. Various
controllers are presented. Be sure to check out the URL:
http://www.aip.com/green/li/html/397pro.html
This article will be at this URL until the end of the month. From there it
goes into archive status and will assume a different web address.
Also, if any of you are having trouble receiving Trickle-L messages (i.e.
redundant messages etc.) please let me know personally at rmead@cybergate.com
Richard Mead
Trickle-L and MIF owner
http://www.cybergate.com/~rmead
Date: Tue, 18 Mar 1997 12:33:25 -1000
From: Willy Pyle <willyp@ALOHA.NET>
Subject: Re: Pump System/ New Technology/ Yet to Appear in Reference Books
Clem Wehner wrote:
>
> There is a new surface water pump set-up for which I have been asked to do
> a survey among irrigators to determine if there is interest in this new
> technology and how it would adapt to their individual needs.
Hi Clem,
How big is this pump? Weight?
How much Flow and Head can it put out?
Estimated Cost? Ball park?
It could have some application here in Hawaii, depending on the above.
Thanks, best Regards,
Willy Pyle
willyp@aloha.net
End of TRICKLE-L Digest - 17 Mar 1997 to 18 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Thu Mar 20 01:02:27 1997
Date: Thu, 20 Mar 1997 00:01:25 -0600
Subject: TRICKLE-L Digest - 18 Mar 1997 to 19 Mar 1997
There are 4 messages totalling 157 lines in this issue.
Topics of the day:
1. suction lysimeters
2. emitter spacing
3. Feb archives/web sites/Internet paper
4. Web site correction
Date: Wed, 19 Mar 1997 10:48:02 -0800
From: Jochen Eberhard <Jochen.Eberhard@T-ONLINE.DE>
Subject: suction lysimeters
Help!!
is there anybody out there using suction lysimeters alone or in
combination with plant sap testing to manage fertigation in row drip
irrigated crops, especially tomatoes.
Thanks for any help.
Jochen
--
_____________________________________________________________
| Jochen Eberhard * * |
| SLFA Versuchsbetriebe ( \ / ) |
| Queckbrunnerhof \ / |
| Dannstadter Str. 91 --- |
| 67105 Schifferstadt (o|o) |
| Germany ( ~~~ ) |
| ( ) |
| Tel: 0049 - 6235 - 2672 ( ) |
| Fax: - - 82741 ( ooO Ooo ) |
| email: Jochen.Eberhard@t-online.de |
|_____________________________________________________________|
Date: Wed, 19 Mar 1997 13:32:27 +0000
From: Michelle Miller <94049860@BELGARIAN.RIV.CSU.EDU.AU>
Subject: Re: emitter spacing
Hi,
I have a query regarding Jochen Eberhard's questions about the pros
and cons of emitter spacing. From the list, I received the initial
questions raised by Jochen and was interested to see how this
discussion would progress. I then received his thank you note and
explanation of his answers. I am not sure I understand this
explanation and seem to have missed the discussion in the middle.
Could we bring this topic into the open again? particularly with
respect to:
- the Q100 constant (what does it represent and how is it
related to water pressure)
- the relationship between emitter flow rate and emitter
spacing - how is it represented and determined?
- and how does one decide the minimum flow rate required to
prevent clogging? Should it be assumed that the use of wider emitter
spacing, solely to achieve higher emitter flow rates to prevent
clogging, is because turbulent emitters are not being used?
Michelle Miller
Postgraduate Researcher (Subsurface Irrigation)
Charles Sturt University
PO BOX 588
Wagga Wagga, NSW 2678,
Australia
Phone: +61 69 334031
Fax: +61 69 332812
Email: 94049860@belgarian.riv.csu.edu.au
Date: Wed, 19 Mar 1997 16:26:08 -0800
From: Richard Mead <rmead@CYBERGATE.COM>
Subject: Feb archives/web sites/Internet paper
The February 97 Trickle-L archives are available on the Best of Trickle-L
section of the Microirrigation Forum (www.cybergate.com/~rmead/best.html).
Topics with associated categories include:
- Best emitter for dirty water (Water problem category)
- Drip Controller with individual station fertilizer control (Engineering
category)
- Lateral Length vs. dripper head loss (Engineering category)
- Lowering Soil pH (Chemical use category)
- Pros & Cons of media and screen filters (Engineering category)
- Tomatoes in salty soil (Effects of crops category)
- SDI in alfalfa (SDI and Effects of crops category)
Regarding the "Best emitter for dirty water" topic: I left out the
political ruckus that occurred throughout that thread and stayed with
pertinent facts. I hope this keeps everyone involved in the "debate" happy.
There have been numerous drip-related companies that have popped up on the
World Wide Web with new and exciting web pages. Some of the company's
representatives have personally told me that they are somewhat shy to
announce their company web site address on Trickle-L. I am announcing below
that the following companies have web sites that have made their debut in
the last six months. Please inform me if your company's web site is not
presented below. By the way, all of these companies will be listed in the
Digital Drip Directory section of the MIF web site.
www.chapindrip.com (Chapin Watermatics)
www.rainbird.com (Rain Bird International, Inc.)
www.SmartRain.com (Smart Rain Corporation, Inc.)
www.dripin.com/dripin (Drip In Irrigation)
www.rootguard-geoflow.com (Geoflow Subsurface Irrigation)
www.inet.net/irrometer (Irrometer Company, Inc.)
www.hardie.com (Hardie/Toro)
www.netafim.usa.com (Netafim Irrigation, Inc.)
www.digcorp.com/asdig (Dig Corporation)
www.naan.co.il (NAAN Irrigation Systems)
Finally, speaking of the World Wide Web and the Internet. The Irrigation
Association's Irrigation Business and Technology magazine recently
published a paper I wrote regarding irrigation information on the Internet.
I have not been able to find this article online and have placed a
hyper-linked version of the paper on the Internet. "Accessing the Internet
for Irrigation Information" can found at the bottom of the Microrrigation
Forum web page. The specific URL is www.cybergate.com/~rmead/iainternet.html
Richard Mead
Trickle-L and MIF owner
Date: Wed, 19 Mar 1997 20:12:16 -0800
From: Richard Mead <rmead@CYBERGATE.COM>
Subject: Web site correction
I delivered a boo boo on the Netafim web site address. The correct Netafim
URL is:
http://www.netafim-usa.com/
not to mention
http://www.netafim.com/
A thousand pardons!!
R. Mead
End of TRICKLE-L Digest - 18 Mar 1997 to 19 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Fri Mar 21 07:11:04 1997
Date: Fri, 21 Mar 1997 03:48:43 -0600
Subject: TRICKLE-L Digest - 19 Mar 1997 to 20 Mar 1997
There are 2 messages totalling 88 lines in this issue.
Topics of the day:
1. again: emitter spacing
2. emitter spacing
Date: Thu, 20 Mar 1997 09:46:36 -0800
From: Jochen Eberhard <Jochen.Eberhard@T-ONLINE.DE>
Subject: again: emitter spacing
Sorry, sorry, sorry,
while beginning my last comment with a thank you note it absolutely was
not my intention to stop the discussion about emitter spacing :-((.
It was just the infant way of a little german guy with minimal knowledge
of the english language to express his thankfullness for the sudden
respond to his simple question.:-))
That is why I added some kind of summery of my understanding of the
answers I recieve for my question. But it seems that my german English
is a little difficult to understand.
So please apologize for the misleading character of my last note and
keep on discussing the problem of choosing the right emitter spacing.
To get the tape selling people into the dicussion: I have heard that
netafim recomments wider emitter spacing but t-tape closer emitter
spacing. Is this only to offset the own product from the commpetitors(?)
or is there any theoretical and practical backround.
I am looking forward to the hopefully continued discussion
Jochen Eberhard
--
_____________________________________________________________
| Jochen Eberhard * * |
| SLFA Versuchsbetriebe ( \ / ) |
| Queckbrunnerhof \ / |
| Dannstadter Str. 91 --- |
| 67105 Schifferstadt (o|o) |
| Germany ( ~~~ ) |
| ( ) |
| Tel: 0049 - 6235 - 2672 ( ) |
| Fax: - - 82741 ( ooO Ooo ) |
| email: Jochen.Eberhard@t-online.de |
|_____________________________________________________________|
Date: Thu, 20 Mar 1997 13:53:16 +0000
From: Michelle Miller <94049860@BELGARIAN.RIV.CSU.EDU.AU>
Subject: Re: emitter spacing
Hi,
I have a query regarding Jochen Eberhard's questions about the pros
and cons of emitter spacing. From the list, I received the initial
questions raised by Jochen and was interested to see how this
discussion would progress. I then received his thank you note and
explanation of his answers. I am not sure I understand this
explanation and seem to have missed the discussion in the middle.
Could we bring this topic into the open again? particularly with
respect to:
- the Q100 constant (what does it represent and how is it
related to water pressure)
- the relationship between emitter flow rate and emitter
spacing - how is it represented and determined?
- and how does one decide the minimum flow rate required to
prevent clogging? Should it be assumed that the use of wider emitter
spacing, solely to achieve higher emitter flow rates to prevent
clogging, is because turbulent emitters are not being used?
Thanks
Michelle Miller
Postgraduate Researcher (Subsurface Irrigation)
Charles Sturt University
PO BOX 588
Wagga Wagga, NSW 2678,
Australia
Phone: +61 69 334031
Fax: +61 69 332812
Email: 94049860@belgarian.riv.csu.edu.au
End of TRICKLE-L Digest - 19 Mar 1997 to 20 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Sat Mar 22 01:48:33 1997
Date: Sat, 22 Mar 1997 00:47:08 -0600
Subject: TRICKLE-L Digest - 20 Mar 1997 to 21 Mar 1997
There are 3 messages totalling 61 lines in this issue.
Topics of the day:
1. Help a newbie..? (2)
2. Help a newbie..? -Reply
Date: Thu, 20 Mar 1997 15:59:41 -0800
From: Robert Taylor <robbert@CCNET.COM>
Subject: Help a newbie..?
I am putting in a drip system in my backyard.
I have added up about 300 lineal feet total.This in a rectangular shape.
I want to put this on one 3/4 valve if possible with a timer.
I am using 3/4 sch 40. The land is flat.
The items are mostly 15 gallon trees. With some flower beds as well.
I was thinking of using the appolo maifolds..adjustable type.
Is this 300 feet alright?
I talked to the people at raindrip and they said thier 5/8's could handle
300 feet.In long rolls.
I believe I have 65 pressure in my pipes.
Thanks
Date: Fri, 21 Mar 1997 02:18:31 -0800
From: Tracy Slavin <TSLAVIN-IBR21D@IBR2GW80.MP.USBR.GOV>
Subject: Help a newbie..? -Reply
I will be on annual leave from 3/21-3/28. If you need assistance before I return, please contact Julie Spezia at x2318 or Marsha Prillwitz at x2397.
Date: Fri, 21 Mar 1997 11:51:28 -0500
From: Tim1Utah@AOL.COM
Subject: Re: Help a newbie..?
First I would get a neutron probe for an analysis of the soils moisture
content. Then I would look at the bulk density. After your lab report comes
back you can consider the capililarity of the soil and determine spacing of
the emitters and tubing.
As far as the pipe size you will want to use the Darcy-Wiesbach
equations with the appropriate Reynolds numbers for pipe less than 2" ID. I
would stay clear of the Hazen-Williams formula unless you are dealing with
larger pipe.
WIth your emitters look for a water passage 1/4th the size of your avg.
particle in the water to avoid bridging. Turbulent flow with pressure
compensation would be nice.
Or better yet, just loop some porous pipe around your bushes until they seem
wet.
Hope this helps.
End of TRICKLE-L Digest - 20 Mar 1997 to 21 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Sun Mar 23 01:47:39 1997
Date: Sun, 23 Mar 1997 00:46:10 -0600
Subject: TRICKLE-L Digest - 21 Mar 1997 to 22 Mar 1997
There is one message totalling 52 lines in this issue.
Topics of the day:
1. Intro from Adams Trade Press editor
Date: Fri, 21 Mar 1997 21:40:50 -0800
From: Richard Mead <rmead@CYBERGATE.COM>
Subject: Intro from Adams Trade Press editor
The following is from Bret Scaliter. Mr. Scaliter is the editor of Adams
Trade Press. The ATP
has contributed immensely to the irrigation community in the past and
specifically on the Internet in the last year. All of the ATP publications
(mentioned later in Mr. Scaliter's intro) are online. Their homepage is
www.aip.com. Be sure to check it out!
R. Mead
Trickle-L owner
--------------------------
Dear Members of Trickle-L:
I would like to introduce myself. I am Bret Scaliter, the new editor
for Adams Trade Press, Inc.'s magazines: *Golf Course Turf &
Irrigation," "Irrigation Journal" and "Landscape and Irrigation."
Producing these monthly/bimonthly magazines is a daunting task--that is
without your help. What I would like to ask from you is your
willingness to share your expertise. In return you will get either
acknowledgement or, in the case that we decide to print your entire
paper, a byline. You will not only be helping me, but help the industry
by providing the most up-to-date information in the field.
I am looking for articles/information for upcoming issues on the
following topics:
For GCTI: Rebuilding Damaged Greens, Pond Management Options,
Irrigating with Reclaimed Water, Insect Update, Aeration/Topdressing
For IJ: Electric Motors, Weather Station Maintenance, Disc and
Cartridge Filters, Down the Field with Linear Move.
For L & I: Irrigation Liability and Litigation, Reducing Water Use, Pond
Management Options, Lightning Protection
I'd like to receive word from you on these topics (or suggestions for
other topics) no later than May 5, so that we have time to work out the
details before the deadlines.
I will attempt to keep you updated on future article/info needs in a
timely manner.
Thank you for your help and interest.
Bret Scaliter
End of TRICKLE-L Digest - 21 Mar 1997 to 22 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Mon Mar 24 01:01:41 1997
Date: Mon, 24 Mar 1997 00:00:18 -0600
Subject: TRICKLE-L Digest - 22 Mar 1997 to 23 Mar 1997
There are 2 messages totalling 111 lines in this issue.
Topics of the day:
1. Help a newbie...Reply (2)
Date: Sat, 22 Mar 1997 23:56:51 -0800
From: Jeff Wiegel <jwiegel@PCEZ.COM>
Subject: Re: Help a newbie...Reply
> Date: Thursday, March 20, 1997 3:59 PM
>
> I am putting in a drip system in my backyard.
>
> I have added up about 300 lineal feet total.This in a rectangular shape.
>
> I want to put this on one 3/4 valve if possible with a timer.
>
> I am using 3/4 sch 40. The land is flat.
>
> The items are mostly 15 gallon trees. With some flower beds as well.
>
> I was thinking of using the appolo maifolds..adjustable type.
>
> Is this 300 feet alright?
>
>
>
> I talked to the people at raindrip and they said thier 5/8's could handle
> 300 feet.In long rolls.
>
> I believe I have 65 pressure in my pipes.
Tim1Utah wrote:
>
> ThanksFirst I would get a neutron probe for an analysis of the soils
moisture
content. Then I would look at the bulk density. After your lab report comes
back you can consider the capililarity of the soil and determine spacing of
the emitters and tubing.
As far as the pipe size you will want to use the Darcy-Wiesbach
equations with the appropriate Reynolds numbers for pipe less than 2" ID. I
would stay clear of the Hazen-Williams formula unless you are dealing with
larger pipe.
WIth your emitters look for a water passage 1/4th the size of your
avg.
particle in the water to avoid bridging. Turbulent flow with pressure
compensation would be nice.
Or better yet, just loop some porous pipe around your bushes until they
seem
wet.
Hope this helps.
Sorry, I cant' stop laughing! But in deference to Robert, I'll add a
comment: You can run up to 8gpm in your 3/4 sch 40 pvc and run it as far as
you have any pressure left. Unless you're using some extraordinary emitter
I'd put a pressure reducing valve on the line also, cut your pressure to
less than the max allowed by the emitter manufacturer, at least to less
than fifty (maybe less than twenty psi?). If 5/8" tubing is what you mean
you are using, it should handle upwards of 5gpm without excessive water
velocity. A 300 ft run is fine, just try to balance the emitter "load"
along the run so the pressure differential from one end to the other is not
too great.
And... don't forget the license for that neutron probe!
Hope this is even 1/4 as helpful.
Date: Sun, 23 Mar 1997 12:51:56 -0800
From: Dad <grapegrower@EARTHLINK.NET>
Subject: Re: Help a newbie...Reply
> Date: Thursday, March 20, 1997 3:59 PM
>>
>> I am putting in a drip system in my backyard.
>>
>> I have added up about 300 lineal feet total.This in a rectangular shape.
>>
>> I want to put this on one 3/4 valve if possible with a timer.
>>
>> I am using 3/4 sch 40. The land is flat.
>>
>> The items are mostly 15 gallon trees. With some flower beds as well.
>>
>> I was thinking of using the appolo maifolds..adjustable type.
>>
>> Is this 300 feet alright?
you seem to be getting some awfully technical info for such a simple
project. a simple pressure regulator (plastic is ok) for less than $10
can be had at your local irrigation store. 20 - 25 psi is enough. name
brand 1 gallon per hour emmitter is good enough. the trees that need
more water put 2 or 3 emmitters spaced out around the tree. i have 300'
runs on my .580" drip tubing with 50 to 60 2 gallon per hopur emitters.
don't let some of these science types fool you. this is easy. check
with your local irrigation store for specifics.
---------------------------------------------------------------------------
-
An IBM user once told me that he has seen the light, and the IBM is
better. I told him he must be confused...The only light he saw was the
glow of the overheating pentium in the darkness of ignorance.
-Robert Carian (me)
** If you have a Macintosh Computer, and want my e-Card, please send me a
**
** message with the subject "e-card request," and I will get one out ASAP
**
End of TRICKLE-L Digest - 22 Mar 1997 to 23 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Tue Mar 25 01:48:14 1997
Date: Tue, 25 Mar 1997 00:46:53 -0600
Subject: TRICKLE-L Digest - 23 Mar 1997 to 24 Mar 1997
There are 5 messages totalling 200 lines in this issue.
Topics of the day:
1. Degree day crop curves (3)
2. GDD Crop Curves
3. Does sand media wear???
Date: Mon, 24 Mar 1997 07:42:19 -0800
From: Tom Spofford <tspofford@GW.WCC.NRCS.USDA.GOV>
Subject: Degree day crop curves
Discussion Group Members,
I am seeking some assistance in locating information for the development
of crop growth curves based upon growing degree days instead of
calendar days. Most of the information that I have encountered is in the
form of individual papers on a specific crop in a specific setting. Does
anyone know of a general #shelf# reference, Graduate Thesis, or Net site
on the subject that might have generic or a range of values for a
diversity of crops? English or metric units are acceptable, with text in
English. Any assistance or potential leads would be appreciated.
Tom
Thomas L. Spofford, Irrigation Engineer
USDA - Natural Resources Conservation Service
National Water & Climate Center, Water Science & Technology Staff
101 SW Main St., Suite 1600
Portland, OR 97204
PH (503) 414-3075 / FAX (503) 414-3101
e-mail: <tspofford@storm.wcc.nrcs.usda.gov>
*********************************************************
"Farming looks mighty easy when your plow is a pencil and you're a
thousand miles from the corn field." Dwight D. Eisenhower (34 th
President of the United States).
*********************************************************
Date: Mon, 24 Mar 1997 09:07:40 -0700
From: Jim Byrne <byrne@HG.ULETH.CA>
Subject: Re: Degree day crop curves
Tom Spofford wrote:
>
> Discussion Group Members,
>
> I am seeking some assistance in locating information for the development
> of crop growth curves based upon growing degree days instead of
> calendar days. Most of the information that I have encountered is in the
> form of individual papers on a specific crop in a specific setting. Does
> anyone know of a general #shelf# reference, Graduate Thesis, or Net site
> on the subject that might have generic or a range of values for a
> diversity of crops? English or metric units are acceptable, with text in
> English. Any assistance or potential leads would be appreciated.
>
> Tom
>
> Thomas L. Spofford, Irrigation Engineer
> USDA - Natural Resources Conservation Service
Tom - please post any reference that you do find to the list.
I have always lamented the short sighted practice of using calender days
for crop coefficient curves when more specific climate or energy indices
could be used just as well. These are theoretically justified as well.
The curves should be tied to specifics of plant physiology - - planting
date at least! :)
Jim
--------------------------------------------------------
James M. Byrne Director
Water Resources Institute University of Lethbridge
Lethbridge, Alberta CANADA T1K 3M4
Tel 403 329 2002 Fax 403 329 2016
"Whether you think you can or you can't, you're right."
Henry Ford
--------------------------------------------------------
Date: Mon, 24 Mar 1997 11:32:33 -0700
From: edmartin@AG.ARIZONA.EDU
Subject: GDD Crop Curves
For those of you interested in GDD or Heat Unit-based crop curves, I've been
doing some work in that area during the past few years. If anyone wants to
contact me directly, please fell free to do so. We have a scheduling
program here at The University of Arizona that uses GDD based Kc.
Data is available for some rows crops (cotton, wheat) and some vegetable crops.
We wrote a paper for the ET symposium last November. A copy of the
Proceedings might be a good place to start to look for references.
Ed Martin
Dr. Edward C. Martin, Ph.D.
Asst. Specialist, Irrigation
Dept. of Ag. & Biosystems Engr.
University of Arizona
Maricopa Ag. Center
37860 W. Smith-Enke Road
Maricopa AZ 85239
Office: (520) 568-2273 Ext. 244
FAX: (520) 568-2556
E-Mail: edmartin@ag.arizona.edu
Date: Mon, 24 Mar 1997 16:39:59 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Does sand media wear???
Folks, a question:
In years past, more than one sand media filter representative
has mentioned to me that the edges of sand media particles "wear"
very slightly over time. This very slight "wear" apparently
dulls the edges of the particles, with this subsequent dulling
decreasing the trapping ability of the media. This in turn was
one reason for increased backflush frequency requirements over
time.
Has anyone else had this information supplied to them? More
importantly, does anyone have data or research showing that this
edge "wear" actually does occur?
Sand media filters do seem to suffer a loss in filtration
efficiency over time. Reasons for this can include (but are not
limited to) poorly-graded sand media, poor backflush performance
of the filter, inadequate backflush flow, less than optimal
backflushing frequency, establishment of preferential flow paths
during backflushing, biological "mats" forming on top of the
media inside the filter, etc. All of these can be temporarily
remedied by replacing the sand media. So could the proposed
edge "wear" discussed also be remedied.
Another list member and I have had quite a spirited discussion
on this over the past week. I would appreciate your comments on
this. Points to consider:
(1) This information was provided by representatives of
manufacturers, not the scientific community, and was
provided 12 to 15 years ago.
(2) My discussion partner and I could recall no references - pro
or con - on media edge wear.
(3) It would seem that sand particles would not wear due to
hardness of the particles with respect to the organics or
other particles filtered.
(4) In counterpoint to #3, even granite does wear in a river bed
over time, due to scouring, water flow, or both.
I must admit this made sense when first presented to me years
ago (many things make sense before reality is considered!), and I
have given it little thought since. In retrospect this could be a
"fix-all," provided to explain away poor backflush performance
of some media filters.
I would appreciate your comments on this. Thanks!
Bryan
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
Date: Mon, 24 Mar 1997 15:57:38 -0600
From: Robert Edling <redling@GUMBO.BAE.LSU.EDU>
Subject: Re: Degree day crop curves
Tom:
Don Slack at the University of Arizona was doing some work on degree day water
use curves several years ago.
Bob Edling
LSU
End of TRICKLE-L Digest - 23 Mar 1997 to 24 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Wed Mar 26 01:49:24 1997
Date: Wed, 26 Mar 1997 00:48:00 -0600
Subject: TRICKLE-L Digest - 24 Mar 1997 to 25 Mar 1997
There are 4 messages totalling 217 lines in this issue.
Topics of the day:
1. again: emitter spacing
2. Sand media filter media edge wear - responses to date ...
3. Emitter & lateral spacing reply from F Lamm
4. Spacing between drippers
Date: Tue, 25 Mar 1997 19:33:52 +0200
From: Jean <henri@ILINK.NIS.ZA>
Subject: Re: again: emitter spacing
At 09:46 AM 3/20/97 -0800, you wrote:
>
>I am looking forward to the hopefully continued discussion
>
Hi Jochen,
I have been following the discussion you initiated about dripper spacing
with interest.
My experience has shown that an applicable decision cannot be taken unless
the development of the root configuration of the plants to be irrigated
together with the related relevant soil characteristics are first taken
into consideration. Let the primary objective be the effective use of
water.
Clogging is one of my last considerations, if at all possible. That problem
should be left to filters ( primary, secondary and tertiary ),cyclones etc
and follow up maintenance. Jean/
Date: Tue, 25 Mar 1997 16:18:29 -0500
From: "W. Bryan Smith" <wsmth@CLEMSON.EDU>
Subject: Sand media filter media edge wear - responses to date ...
I have received several responses from list members concerning sand
media filter media edge wear. These were addressed directly to me,
so I have included them below for the benefit of the list.
I will continue to do this with others sent directly to me unless
directed not to do so by the sender.
Thank you for your responses. I really appreciate your time and
effort.
Bryan
===========================================
To: wsmth@CLEMSON.EDU
From: "J.D. Oster" <oster@mail.ucr.edu>
Subject: Re: Does sand media wear???
X-PMFLAGS: 34078848 0
Any mineral will dissolve, however slowly, if it is exposed to water
provided that the water does not contain as much of the chemical
constituents as it would if allowed to fully equilibrate with the
mineral.
It's the solubility product of the mineral that is in question and
the chemical composition of the water with which it comes into contact.
Then there are the amendments, particularly acids, which when added to
water can speed up the rate some minerals will dissolve. Perhaps you know a
soil chemist or a geologist who could fill in the details of the solubility
product and how it applies to silicates.
J.D.(Jim) Oster
Dept. of Soil & Env. Sciences
University of California
Riverside, CA 92521
Phone (909)787-5100
FAX (909)787-5522
===========================================
Date: Tue, 25 Mar 1997 13:14:39 +0930
Subject: MEDIA FILTERS
To: wsmth@CLEMSON.EDU
X-PMFLAGS: 33554560 0
Bryan,
Yes, i too have told that media does wear. I suggest to growers that
the correct media should be sharp, that is crushed and graded granite material.
the sharp irregular traps the organic material.
Over time the material becomes more rounded, probably due to the
grinding action of the particles as the media bed moves and lifting during
backwash phase.
I have no scientific evidence to support this claim.
Denis Sparrow
===========================================
Date: Tue, 25 Mar 1997 06:28:55 -0800
From: Robert Richardson <rainbird@comnet.ksc.net.th>
To: wsmth@CLEMSON.EDU
Subject: Re: Does sand media wear???
X-PMFLAGS: 34078848 0
In regard to sand media wearing, I doubt it due to the very resistant
nature of the quartz. I have never heard of any data resulting from
an investigation of this loss in filtration efficiency. I believe
bacterial films blunt the edges of the quartz, reducing tortuosity and allowing
deeper penetration of OM into the sand bed, thereby necesitating more
frequent back-flushing..
===========================================
Date: Tue, 25 Mar 1997 08:54:30 -0600
From: James Prochaska <jnmtexas@startel.net>
To: wsmth@CLEMSON.EDU
Subject: Re: Does sand media wear???
X-PMFLAGS: 34078848 0
You may try thinking about how rock hounds polish rocks. This type
of tumbling action takes place between sand particles while the unit is
flushing. One has to consider though, it will take a lot of flushing
to really grind down the sharp edges. If that much flushing is
accuring, then I would either add more tanks, change the media more often,
or better yet, go to disc filtration.
-- End --
=|===|===|===|===|===|===|===|===|===|===|=
W. Bryan Smith
Area Extension Agent - Irrigation / Water Quality
Clemson Extension Service
P.O. Box 160
Newberry, South Carolina 29108 USA
Office: 803 276-1091 FAX: 803 276-1095
Internet: wsmth@clemson.edu
=|===|===|===|===|===|===|===|===|===|===|=
All opinions are my own and not reflective of the
policies of Clemson University or the Cooperative
Extension Service.
Date: Tue, 25 Mar 1997 14:55:26 -0600
From: Freddie Lamm <FLamm@OZNET.KSU.EDU>
Subject: Emitter & lateral spacing reply from F Lamm
I BELIEVE JEAN WROTE:
My experience has shown that an applicable decision cannot be taken unless
the development of the root configuration of the plants to be irrigated
together with the related relevant soil characteristics are first taken
into consideration. Let the primary objective be the effective use of
water.
FREDDIE LAMM REPLIED:
I really hesitated to reply because this is an often traversed topic.
In fact I would guess the archives have repeatedly hit on this.
Perhaps Richard Mead could point us back to some of the earlier
discussions.
THOUGH I HESITATED, I think Jean makes a good point and there is
some literature that conceptually discusses these items. Uniformity
can be approached from a hardware standpoint as we engineers often do
in our engineering practices and standards (IE. ASAE Engineering
Practice EP-458). But REALITY also reflects the crop, soil and even
climate considerations. That doesn't discount the need for quality
hardware, it just says don't forget there are other factors affecting
uniformity.
Two papers that may be of interest that are not really specific to
microirrigation are:
Seginer, I. 1978. "A note on the economic significance of uniform
water application". Irrigation Science 1:19-25.
Seginer, I. 1979. "Irrigation uniformity related to the horizontal
extent of the root zone." Irrigation Science 1:89-96.
I have found these papers useful in helping to formulate some of my
own ideas about the interaction of hardware uniformity and the other
crop, soil, etc. factors for both SDI and In-canopy Center Pivot
Sprinkler Irrigation.
Freddie
*
-------------------------------------------------------------------
Freddie Lamm *
Research Agricultural Engineer *** o
KSU Northwest Research-Extension Center ***** /|\
105 Experiment Farm Road *******\\
Colby, Kansas 67701-1697 *********
Ph. 913-462-6281 ***********
FAX 913-462-2315 *************
Email:flamm@oznet.ksu.edu It's all downhill from here.
------ THERE'S NO DOMAIN LIKE OZ, THERE'S NO DOMAIN LIKE OZ. ------
Date: Wed, 26 Mar 1997 10:18:18 +0930
From: thomson.tony@WPO.PI.SA.GOV.AU
Subject: Spacing between drippers
What are the experiences of Discussion Group Members with
Dripper spacing ?
In no-wind conditions
the rule of thumb for sprinkler spacing is
60% of wetted diameter.
With drippers,
to form a "wetted sausage "
are drippers typically spaced at 60% of wetted diameter
to achieve some some leaching where the dripper patterns overlap ?
Regards
Tony
thomson.tony@pi.sa.gov.au
End of TRICKLE-L Digest - 24 Mar 1997 to 25 Mar 1997
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>From LISTSERV@crcvms.unl.edu Thu Mar 27 01:47:00 1997
Date: Thu, 27 Mar 1997 00:45:36 -0600
Subject: TRICKLE-L Digest - 25 Mar 1997 to 26 Mar 1997
There are 4 messages totalling 147 lines in this issue.
Topics of the day:
1. Spacing between drippers
2. GDD Crop Coefficients - Follow-up to Howell's Reply
3. GDD Crop Coefficients (2)
Date: Wed, 26 Mar 1997 09:23:34 -0800
From: Robert Richardson <rainbird@COMNET.KSC.NET.TH>
Subject: Re: Spacing between drippers
<HTML><BODY>
Drippers for row crops should be placed to achieve a wet strip where the
discrete emitters coalese to form the strip. Leaching is not particularly
useful for short-term row crops and would interfere with fertigation programs.
Actual field spacing to be chosen should be based on soil type with sandy
soils requiring shorter intervals between emitters to achieve the strip.
<BR>
</BODY>
</HTML>
Date: Wed, 26 Mar 1997 06:21:17 -0800
From: Tom Spofford <tspofford@GW.WCC.NRCS.USDA.GOV>
Subject: GDD Crop Coefficients - Follow-up to Howell's Reply
Trickle-L and Irrigation-L,
Terry brought up some great points that need to be kept in mind when dealing with GDD's. An item
he overlooked was a reference on the subject that he steered me too. The reference gets into more
detail on Terry's discussion. While the reference does not get directly at stages and coefficients, it
does discuss regional variability and sensitivity.
The reference Terry lead me to is: "Modeling Plant and Soil Systems", American Society of
Agronomy (ASA), Handbook No. 31, 1991, ISBN.
I have not seen any comments or responses from non USA members on this subject and would like
greatly to hear form you.
Thomas L. Spofford, Irrigation Engineer
USDA - Natural Resources Conservation Service
National Water & Climate Center, Water Science & Technology Staff
101 SW Main St., Suite 1600
Portland, OR 97204
PH (503) 414-3075 / FAX (503) 414-3101
e-mail: <tspofford@storm.wcc.nrcs.usda.gov>
*********************************************************
"Farming looks mighty easy when your plow is a pencil and you're a thousand miles from the corn
field." Dwight D. Eisenhower (34th President of the United States).
*********************************************************
Date: Wed, 26 Mar 1997 06:45:30 -0600
From: "Terry A. Howell" <tahowell@AG.GOV>
Subject: GDD Crop Coefficients
3/26/97
Trickle-L and Irrigation-L:
I am responding to Tom Spofford's posted requests to these groups. Tom and I have already corresponded on this subject. But since several good posts have come in, I wanted to throw out for discussion some of my observations about GDD based crop curves.
First there is no standard method for computing GDD, and the user must be aware of this. Also you can't simply convert from one GDD method to another.
Second GDD is crop specific so you end up tracking N number of indices where N is your number of crops you are following. Also, GDD tracks crop development (phenology or growth stages) and not necessarily crop growth (biomass).
I do recommend the GDD base, but we have attempted to standardize all our values using one GDD method and only two temperature thresholds (a base temperature and an upper maximum) for a given species (we work on corn, wheat, sorghum, cotton, soybean, alfalfa, grass, sugar beet, and penut).
The GDD method we use follows:
GDD = [(Tmax + Tmin)/2] - Tbase
Tbase <= Tmax <= Tupper
Tbase <= Tmin <= Tupper
where Tmax and Tmin are daily maximum and minimum air temperatures, Tbase is the base (lower) temperature for development, and Tupper is the upper (maximum) temperature for development.
Users should be aware that plant scientists may not agree that either Tbase or Tupper are constants for a given species much less constant for all growth stages and/or even specific cultivars (varieties).
This method is what I call the "corn" method because it basically follows much of the pioneering corn development modeling.
The "cotton" GDD method follows:
GDD = [(Tmax + Tmin)] - Tbase
GDD >= 0 {no limits on either Tmax or Tmin just GDD}
A large number of modelers, besides just cotton folks, use this simpler GDD model.
In my environment, Texas High Plains -- 4+ million irrigated ac. (the third or fourth largest irrigated state in the US if it was a separate state far surpassing the rest of Texas even), with our relatively cool night temperatures (high elevations of 3,000 to 3,800 ft) coupled with extremes in both Tmax (several days over 100F each season) and Tmin make the use of the "corn" model seem to work better (especially for corn and wheat but not much difference for cotton).
I know I can't convince anyone to change their "pet" GDD method. But this is a major problem for users of GDD based Kc data, especially if you don't have your own data base. But it is no different than recognizing that the use of Kc data must also be corrected for ETr methods used in developing the Kc data. Even Kc data developed with a Kimberly Penman equation will not "exactly" match Kc data when computed with an "ASCE Manual #70" Penman-Monteith equation, especially for a a site different from Kimberly, ID.
I am not aware of anyone taking any crop ET data (from any recognized world lysimeter site) and computing Kc values for various specific ETr equations (Kimberly Penman, Penman-Monteith, FAO Penman, etc.), and then comparing them to Kc values from another site (world recognized lysimeter site) computed similarly.
I'm interested in your comments and will set back and "listen," and I'm sure I will be "enlightened" by both discussion groups as I have been in the past!
Terry Howell
*********************************************************************
* Terry A. Howell, Ph.D., P.E. (806) 356-5746 (voice) *
* USDA-ARS (806) 356-5750 (fax) *
* P.O. Drawer 10 tahowell@ag.gov (e-mail) *
* 2300 Experiment Station Rd. (shipping) *
* Bushland, TX 79012 http://www.net.usda.gov/cprl/ (Internet) *
* ........ Make every drop count! Whose water is it? ....... *
*********************************************************************
Date: Wed, 26 Mar 1997 17:18:04 -0600
From: "Terry A. Howell" <tahowell@AG.GOV>
Subject: Re: GDD Crop Coefficients
3/26/97
Trickle-L and Irrigation-L:
I did notice an error (should be obvious, but these things can grow and spread) in my GDD equation for the "cotton" method. It should have been
GDD = [(Tmax + Tmin)/2] - Tbase
GDD >= 0 {no limits on either Tmax or Tmin just GDD}
Sorry if this misled anyone.
Terry
*********************************************************************
* Terry A. Howell, Ph.D., P.E. (806) 356-5746 (voice) *
* USDA-ARS (806) 356-5750 (fax) *
* P.O. Drawer 10 tahowell@ag.gov (e-mail) *
* 2300 Experiment Station Rd. (shipping) *
* Bushland, TX 79012 http://www.net.usda.gov/cprl/ (Internet) *
* ........ Make every drop count! Whose water is it? ....... *
*********************************************************************
End of TRICKLE-L Digest - 25 Mar 1997 to 26 Mar 1997
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>From LISTSERV@crcvms.unl.edu Fri Mar 28 01:03:08 1997
Date: Fri, 28 Mar 1997 00:01:52 -0600
Subject: TRICKLE-L Digest - 26 Mar 1997 to 27 Mar 1997
There are 4 messages totalling 118 lines in this issue.
Topics of the day:
1. Disc Permeameters
2. Help a newbie..? (2)
3. Emitter spacing
Date: Thu, 27 Mar 1997 14:39:11 +1100
From: Darryl John Ross <rossd@SLIM.AGVIC.GOV.AU>
Subject: Disc Permeameters
I having been reading on how disc permeameters can be used to provide
information for irrigation. For example dripper spacings. We have a
disc permeameter which is set up for supplying water at pressures
less than or equal to zero, but know one really knows how to use it.
If anybody has used a disc permeameter could they please help me with
some practical information on how to use them in the field. I have
read some of the theory about how K and sorbtivity are derived, but
I still can't get my mind around how to apply this to the real world.
Thanks,
Darryl Ross (Department of Agriculture, Victoria, Australia)
Date: Thu, 27 Mar 1997 22:59:06 +1100
From: Wally Menke <wallym@OZEMAIL.COM.AU>
Subject: Re: Help a newbie..?
At 11:51 AM 21/03/97 -0500, you wrote:
> First I would get a neutron probe for an analysis of the soils moisture
>content. Then I would look at the bulk density. After your lab report comes
>back you can consider the capililarity of the soil and determine spacing of
>the emitters and tubing.
> As far as the pipe size you will want to use the Darcy-Wiesbach
>equations with the appropriate Reynolds numbers for pipe less than 2" ID. I
>would stay clear of the Hazen-Williams formula unless you are dealing with
>larger pipe.
> WIth your emitters look for a water passage 1/4th the size of your avg.
>particle in the water to avoid bridging. Turbulent flow with pressure
>compensation would be nice.
>
>Or better yet, just loop some porous pipe around your bushes until they seem
>wet.
>Hope this helps.
>
I think the above would make a home gardener run for cover! I don't believe
"pourous pipe" could be regarded as a serious product surely?, I've just
seen 90,000 m (295,200 ft) of this installed 2 years ago that no longer works.
Wally Menke
Triangle Filtration
Date: Thu, 27 Mar 1997 07:19:22 -0500
From: Tim1Utah@AOL.COM
Subject: Re: Help a newbie..?
Wally, Check your funny bone and make sure it is still connected
properly.................
Date: Thu, 27 Mar 1997 19:47:12 -0800
From: Manrique Brenes <mjbrenes@UCDAVIS.EDU>
Subject: Emitter spacing
Reviving the discussion on emitter spacing, I would like to add a few =
ideas to the debate about it.
First let me state that I believe that the ideal drip system would have:
1- A very thin and resistant wall.
2- High uniformities and a small inside diameter.
3- Emitters closely spaced that would be resistant to plugging.
4- Very low emitter exponents and CVs.
As you can see all of the above are a game of trade-offs. Thin walls are =
more economical but tend to be damaged easily, small diameters are also =
economical but are limited to short runs due to low uniformities. It has =
been agured that closely spaced emitters necessarily have to deliver =
lower flows per emitter requiring longer and/or narrower flowpaths which =
tend to clog easier. Finally low emitter exponents tend to have =
membranes that do not behave uniformly, specially as time passes.
These tradeoffs vary for every particular situation according to =
different agricultural practices and the cost of the materials locally.=20
In the specific case of emitter spacing I would agree that different =
soil types may require different emitter spacings, however, assuming =
that we are talking in terms of flow/unit length, it is in general =
better to have as many emitters as possible. The more emitters the =
better the actual water distribution. Here, I am not talking about EU or =
CU, I am referring to how well the actual soil profile is wetted. To =
visualize this lets use two extreme situations:
* a drip line with emitters spaced at 1.0 m with a flow of 4 l/h (that =
is 4 l/h/m)
* a drip line with 5 emitters spaced at 0.2 m with a flow per emitter of =
0.8 l/h ( that is 4 l/h/m)
Note that the two systems have the same flow/unit length, even if they =
both had the same CU and/or EU the emitter with closer spacing would =
yield a much better wetting front in the soil profile. This is specially =
true of systems that are working in real time, using short irrigation =
cycles. Needless to say that we would have not only better water =
distributions but also a much better distribution of the chemicals =
delivered by the system. Also keep in mind that if an emitter plugs the =
loss in flow is much smaller when you have 5 times the amount of =
emitters, and the plants near that emitter would suffer less since it =
may receive water from the other emitters that are just 20 cm away.
Lets not forget the fact that the initial limitation was the possibility =
of plugging. I think that the technology to produce low volume emitters =
with a resistance to plugging as good any "high" flow emitter has been =
used for a long time already and it is therefore hard to justify spacing =
that are not on the order of 0.3 m at least, 0.2 m is even better.
Manrique Brenes
End of TRICKLE-L Digest - 26 Mar 1997 to 27 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Sat Mar 29 01:40:35 1997
Date: Sat, 29 Mar 1997 00:03:09 -0600
Subject: TRICKLE-L Digest - 27 Mar 1997 to 28 Mar 1997
There are 3 messages totalling 120 lines in this issue.
Topics of the day:
1. Degree Days etc.
2. <No subject given>
3. Homepage announcement
Date: Fri, 28 Mar 1997 11:28:59 -0600
From: "J.D. Oster" <oster@MAIL.UCR.EDU>
Subject: Degree Days etc.
>Date: Tue, 25 Mar 1997 11:04:48 -0800
>From: Mike SHANNON <MSHANNON@USSL.ARS.USDA.GOV>
>To: oster@mail.ucr.edu
>Cc: mguzy@USSL.ARS.USDA.GOV
>Subject: Degree Days etc.
>
>Michael Guzy's opinions on the subject matter are
>whole-heartedly sanctioned by me, despite his disclaimer.
>
>It was my respect for his knowledge on this matter that led
>me to forward your memo to him. I concur with his
>interpretations.
>
>
J.D.(Jim) Oster
Dept. of Soil & Env. Sciences
University of California
Riverside, CA 92521
Phone (909)787-5100
FAX (909)787-5522
Date: Fri, 28 Mar 1997 11:29:02 -0600
From: "J.D. Oster" <oster@MAIL.UCR.EDU>
Subject: <No subject given>
Date: Tue, 25 Mar 1997 10:27:22 -0800
From: Michael Guzy <mguzy@USSL.ARS.USDA.GOV>
To: oster@mail.ucr.edu
Cc: mshannon@USSL.ARS.USDA.GOV
Subject: Re: Degree day crop curves -Reply
Dr. Oster please forward this to trickle
The question begs for explanation differentiating growth from
development, including discussion on factors influencing both.
No reasonable crop model parameterizes development using
calendar rather than thermal time. The only time calendar days
are acceptable as the measure of phenological time is when the diurnal
temperature cycle from day to day is invariant. Degree day clocks usually
work quite well to simulate the progression from germination,
emergence, vegetating, flowering, fruiting, ripening, senescing.
Some better phenological clocks have been tested that are functions of
both light and temperature. Light could be photoperiod, or light could
be intensity.
Development however is different from biomass accumulation.
Biomass accumulation depends on light, water, nutrients and temperature.
Because of the secondary influence of temperature on growth,
growth curves are acceptable using calendar days.
Because of the temperature dependence of
physiological processes (cf. Arrhenius Law), calendar days for time
are not the best solution.
So you see there is no silver bullet that allows an oversimplified
view of the reality. What approach you take depends upon the
problem you're solving. Which varying factors are going to
influence irrigation demand the most? Maybe you need a
system of equations including all the aforementioned influences
on growth and development.
Relevant information is scattered throughout the literature and
goes way back in time. You might check out some text books on
crop modelling simulation for compilations of earlier references.
Then you could do some searches of databases to find newer
references. From your question I cant tell if you'd be satisfied
by looking at the book Marvin Jensen edited (1990) which you
probably already know about.
The preceeding is just an independent statement of opinion
that makes no claim to represent the policy of my employer.
mguzy@USSL.ARS.USDA.GOV
J.D.(Jim) Oster
Dept. of Soil & Env. Sciences
University of California
Riverside, CA 92521
Phone (909)787-5100
FAX (909)787-5522
Date: Fri, 28 Mar 1997 14:15:19 -0600
From: "J.D. Oster" <oster@MAIL.UCR.EDU>
Subject: Homepage announcement
Greetings from Riverside California:
This is an announcement about a homepage you can access on the Web where the
Cooperative Extension Specialists in the Department of Soil and
Environmental Sciences will be posting information. We hope the information
will be useful! Constructive (or negative) comments about what you find
there would be particularly appreciated.
The main address is: http://esce.ucr.edu.
My subaddress is: http://esce.ucr.edu/oster
J.D.(Jim) Oster
Dept. of Soil & Env. Sciences
University of California
Riverside, CA 92521
Phone (909)787-5100
FAX (909)787-5522
End of TRICKLE-L Digest - 27 Mar 1997 to 28 Mar 1997
****************************************************
>From LISTSERV@crcvms.unl.edu Mon Mar 31 01:03:21 1997
Date: Mon, 31 Mar 1997 00:02:20 -0600
Subject: TRICKLE-L Digest - 28 Mar 1997 to 30 Mar 1997
There is one message totalling 138 lines in this issue.
Topics of the day:
1. M. Brene reply about emitter spacing.
Date: Sun, 30 Mar 1997 22:20:51 -0600
From: FLamm@OZNET.KSU.EDU
Subject: M. Brene reply about emitter spacing.
FREDDIE LAMM REPLIED:
M. Brene made many good comments and correctly covered the tradeoffs
between his IDEAL system and what reality presently offers. He has
given these issues some thought and is not seeking a one-size-fits-
all solution.
However,
I do have a few additional comments about a few of his statements.
MANRIQUE BRENES SAID:
It is in general better to have as many emitters as possible. The
more emitters the better the actual water distribution. Here, I
am not talking about EU or CU, I am referring to how well the
actual soil profile is wetted.
FREDDIE LAMM REPLIED: The comments are generally correct, and the
examples were good, BUT even though your thoughts are correct, the
integrating effect of soil water redistibution and water uptake by a
disperse root system CAN BE (BUT, NOT ALWAYS) such a significant
factor that after a point closer emitter spacing becomes a moot
improvement. I realize that's technical nitpicking, but I enjoyed
your thoughts so much, I wanted to jump in.
MANRIQUE BRENES SAID:
I think that the technology to produce low volume emitters with a
resistance to plugging as good any "high" flow emitter has been used
for a long time already and it is therefore hard to justify spacing
that are not on the order of 0.3 m at least, 0.2 m is even better.
FREDDIE LAMM: Once again, I argue with you on this one. In general,
I agree with your good assessment of what's practical. BUT, the
correct emitter spacing is still going to be dictated by the
functioning crop root system zone and the soil characteristics
affecting water redistribution.
Consider these brain teaser examples for thought,
Brain Teaser #1.
We say that one of the advantages of microirrigation is the high
uniformity when in reality microirriagtion is usually non-uniform. A
broadcast application of irrigation is uniform while microirrigation
is usually applied at a point or as a line source. If
spacial uniformity is not a requirement in all directions why would
uniformity at the 0.2 or 0.3 m range be so important?
Brain Teaser #2
You are microirrigating trees spaced on 50 ft squares. Would the
0.2- 0.3 m the best spacing for all soil types?
Brain Teaser #3
You are irrigating a field 20 x 20 ft that is a porous sand
overlaying a relatively impervious clay lens at 2 ft. You have a
scavenger crop that has a very disperse root system that covers most
of the field area. Would a few emitters be almost as good as a
bunch of closely spaced emitters?
Brain Teaser #4
Manriques Brenes becomes the world's recognized expert on
microirrigation. In a speech before the United Nations, Brenes
states "In general the emitter spacing should be in the 0.2 - 0.3 m
range." Richard Mead becomes President-for-life of the small country
of Dripovia and issues a degree that all microirrigation systems must
use a 0.2-0.3 m emitter spacing.
***Alternative ending #1****
Mega dripline manufacturer, ScotchTape revolutionizes the industry
with a new drip tape with its patented non-adhesive flowpath with
0.35 m emitter spacing. The dripline is so cheap, they're
practically giving it away, but President Mead's word is law. Later
that year Dripovia is thrown into chaos as peasant Freddie Lamm leads
a revolt pleading for cheaper irrigation systems. Manrique Brenes
pleads for calm, but it is too late.
****Alternative ending #2****
Peasant Freddie Lamm develops a new SDI technique to
apply an animal-based fertilizer slurry. Since the slurry contains
large particles, large emitters are required necessitating a 0.4
emitter spacing to avoid excessive flowrates. Although Peasant Lamm
is praised by both the Commerce Dept and Environmental Protection
Agency of Dripovia, President Mead is incensed and has Peasant Lamm
thrown into prison as a heretic. Later that year Dripovia is thrown
into chaos as everyone is up to their knees in unused animal-based
fertilizer slurry. Manrique Brenes pleads for calm but it is too late.
***MORAL TO BRAIN TEASER #4: Be careful making general rule-of-thumb
statements that politicians or regulators may incorporate into laws
without incorporating common sense in at the same time.
OBVIOUSLY THIS WAS AN ATTEMPT AT HUMOR. NO OFFENSE IS MEANT,
PARTICULARLY TO **PRESIDENT-FOR-LIFE** RICHARD MEAD. No sense
upsetting the Pres.
Anyway, Manrique Brenes had a lot of good thoughts. My last challenge
is that IN MY OPINION:
The ideal microirrigation system is one that economically and
physically meets its purposes without unduly affecting the
environment.
In my opinion, some of your items are not requirements. Some are
JUST practical or economical constraints that we have to face today.
They may not always fall along those same lines.
But at Dennis Miller says, "Thats just my opinion, I could be wrong?
Freddie
*
**********************************************************************
Freddie R. Lamm * o
Research Agricultural Engineer *** /|\
KSU Northwest Research-Extension Center *****\\
105 Experiment Farm Road *******
Colby, Kansas 67701-1697 *********
Phone: 913-462-6281 ***********
FAX: 913-462-2315 *************
E-Mail: flamm@oznet.ksu.edu It's all downhill from here!
**** There's no domain like OZ, There's no domain like OZ. ****
End of TRICKLE-L Digest - 28 Mar 1997 to 30 Mar 1997
****************************************************
Prepared by Steve Modena, AB4EL
Suggestions and comments to: modena@SunSITE.unc.edu