TRICKLE-L digests for DECEMBER 1995

From ab4el@ab4el.com Sat May 18 00:00 EDT 1996
From: Stephen Modena <modena@SunSITE.unc.edu>
Message-Id: <96051801.modena@sunsite.unc.edu>
Subject: TRICKLE-L LOG9512
Date: Sat, 18 May 1996 00:01:00 -0400 (EDT)

This is the compendium of TRICKLE-L digests for December 1995.

It was prepared from the daily digest mailings. Some digests
may be missing, because occasional mailings are lost en route.

From root@crcnis1.unl.edu Fri Dec 1 16:45 EST 1995
Date: Fri, 1 Dec 1995 10:36:59 -0600
Message-Id: <199512011636.AA16902@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 365

Contents:
Introduction and Survey Response (tahowell@ag.gov)
(evan@griffith.dwr.csiro.au (Evan Christen))
duplicate mailings (<rpolloc@eng.clemson.edu>)
Re: (flowers@Rt66.com (Wilderness Flowers))
Re: duplicate mailings (Stephen Rawlins <srawlins@ncw.net>)
Duplicate mailings (applies only to those having problems) (MEAD2513@aol.com)

Date: Thu, 30 Nov 1995 10:34:52 -0800
From: tahowell@ag.gov
Subject: Introduction and Survey Response

TRICKLE-L:

Richard Mead asked me to introduce myself to the Trickl-L discussion
group as a new subscriber and to answer the survey questions.

I am an irrigation researcher specializing in evapotranspiration and system
design and management. I've worked in irrigation research since 1970. I'm
currently the Research Leader of the USDA-Agricultural Research Service Water
Management Research Unit at Bushland, Texas USA (located near Amarillo, TX).
I've been at Bushland since 1983, and prior to that worked for New Mexico State
Univ., Texas A&M Univ., and ARS at Fresno, CA. My academic training is in
agricultural engineering, and I hold B.S., M.S., and Ph.D. degrees from Texas
A&M Univ. I am an adjunct professor of Biological Systems Engineering at the
University of Nebraska at Lincoln.

My work is focused on improving water use efficiency in irrigated agriculture
in the Southern Great Plains of the U.S. In the Texas high plains alone, there are >
than about 1.7 million ha of irrigated land. Irrigation is supplemental to the
sparse, erratic rainfall (470 mm annual average; 1/2 half during the summer growing
season). Irrigation is mainly from the Ogallala aquifer, which is being depleted.
This region was developed for irrigation in the post W.W.II period when natural gas,
and deep well turbine pumps became widely available. The region's irrigation mainly
used the relatively flat, heavy-textured clay loam soils initially, which were suited
to graded furrow irrigation. Now the area is about 50:50 graded furrow and center
pivot sprinklers. The region produces mainly cotton (south of where I work), corn,
sorghum, and winter wheat. The region is a major cattle feeding center (1/2 of all
cattle on feed in the U.S. are within a 100 mi. radius). Other important irrigated
crops include sugarbeet, peanut, soybean, alfalfa (hay), and some grass (grazed and
hay). Irrigation is practically all 'privately' developed (in most of the area
groundwater is considered to be owned by the surface land owner) although subsidized
by Federal Govt. Farm Programs. The region is very water and energy conservation
oriented. Water quality (including salinity) is not an overriding concern.

Our 'home page' at <http://www.net.usda.gov/cprl/> contains considerably
more information as well as information about our research unit including
some available software and a list of our recent publications.

SURVEY RESPONSES:
1. Experience: I've worked in trickle research (design and system performance) since
1970.

2. Crops: We work with corn and lawn grass at this time using subsurface drip.

3. SDI depth: For corn 12-15 inches for lawn grass 6-8 inches.

4. Drip problems: Your usual ones - filtration, emitter failures, rodent and animal
damage.

5. Fertigation: We use regular liquid urea (N source) and usually inject phosphoric
acid (mainly to maintain drip lines; but also a P source). We are using root
intrusion protected materials in the grass research plots and don't consistently
inject the acid but do on occasion.

6. Reduced fertilizer/water use: Not really. This of course needs some
qualification. Drip doesn't change necessarily the plant need for water or nutrients.
It does provide a means to apply both to the crop with a minimum of losses. Water
requirement of a crop in our area depends on rainfall received (semi-arid area so its
not dependable and very erratic) and evaporative demand (mainly a climatic index).
Crops use of water is closely tied to its dry matter growth (~net photosynthesis)
since the same plumbing system is used (the leaf stomata) for both processes. The
only source of irrigation application loss that drip (by itself) can eliminate are
airborne droplet evaporation (if we don't include spitters, and mini-sprinklers as
drip devices) and net canopy interception losses during sprinkling. Essentially flood
irrigation also eliminates these two direct application losses as well. Other
application losses like surface runoff, deep percolation, and soil surface evaporation
should be eliminated or greatly minimized by drip if good management is used (but
using a drip method does not guarantee 'good management' although I think it makes
'good management' easier to accomplish). All of these factors can be applied to
nutrients as well. I have data to support both higher and lower water use and can
argue both ways! It all depends on which apple you compare with which orange! In my
area, the real "KEY" to saving water is taking advantage of our rainfall resource and
that remains very difficult and complex even with drip.

7. Water quality problems: Yes, our main problem is low H2O in our water! No, our
water is from the Ogallala aquifer and very good quality. Except yesterday, we just
heard DOE admit offsite explosive chemicals (basically TNT) in a perched water table
outside Pantex (about 25 miles from us) so we may be able to both irrigate and remove
our drip lines with one BLAST soon!!!

8. How frequent: Didn't I read something in Ann Lander's column recently about this!
We have not seen much difference from irrigating as needed every 15 min., once a day,
or once a week on our clay loam soil IF you supply the right amount of water when you
do irrigate. Of course, irrigation frequency affects rainfall retention so you have
to out smart Mother Nature!

9. Rodent Damage/Control: Yes and animal damage [coyotes, dogs, badgers, deer, Deere
(the green kind, I wonder if IHCAESE is likes drip lines too), etc.]. Control - we
don't know! We don't see as many problems where we sufficiently irrigate.

10. Uniformity/Design: Good to excellent. Most of our systems are research oriented
so we design for long life, high uniformity, and reliable performance.

11. How did you find this list: From the WMRL home page.

Terry Howell

*********************************************************************
* Terry A. Howell, Ph.D., P.E. (806) 356-5746 *
* USDA-ARS (806) 356-5750 (Fax) *
* P.O. Drawer 10 tahowell@ag.gov (E-mail) *
* Bushland, TX 79012 http://www.net.usda.gov/cprl/ (Internet) *
* *
* 1/2 mi. West I-40 South Access Rd. (shipping) *
* *
* U.S. Department of Agriculture, Agricultural Research Service is *
* an equal opportunity employer and all agency services are *
* available without discrimination. *
*********************************************************************

Date: Thu, 30 Nov 1995 16:49:44 -0600
From: evan@griffith.dwr.csiro.au (Evan Christen)
Subject:

>Richard re:this message on air /irrigation injection is there any way to
>email contact the sender? I am on the organizing committe for this >years NM
>Organic Commodities annual meeting and would like to invite the >sender to
speak.

The sender was Dave Enyeart Dr Evan Christen
Irrigation and Drainage Management for Horticulture
CSIRO Division of Water Resources
Griffith Laboratory
Griffith
NSW 2680
Australia

Fax # 61 69 601600

Date: Thu, 30 Nov 1995 19:53:17 -0500
From: <rpolloc@eng.clemson.edu>
Subject: duplicate mailings

Dr. Mead,

Please do something about the duplication
of the TRICKLE-L digest list by each
applicant's input. It's a great
discussion but its filling up my email.
thanks

Robert
rpolloc@eng.clemson.edu

Date: Thu, 30 Nov 95 18:57:04 MST
From: flowers@Rt66.com (Wilderness Flowers)
Subject: Re:

thanks for the info
Martin>
>
>>Richard re:this message on air /irrigation injection is there any way to
>>email contact the sender? I am on the organizing committe for this >years NM
>>Organic Commodities annual meeting and would like to invite the >sender to
>speak.
>
>The sender was Dave Enyeart >Dr Evan Christen
>Irrigation and Drainage Management for Horticulture
>CSIRO Division of Water Resources
>Griffith Laboratory
>Griffith
>NSW 2680
>Australia
>
>Fax # 61 69 601600
>
>
>
Martin Connaughton
Wilderness Flowers
Rt.19 Box 111D
Santa Fe, NM 87505

"It could only be fresher if you grew it"

Date: Thu, 30 Nov 1995 19:14:47 -0800
From: Stephen Rawlins <srawlins@ncw.net>
Subject: Re: duplicate mailings

THAT INCLUDES THIS DUPLICATE MESSAGE!!!!

At 06:51 PM 11/30/95 -0600, you wrote:
>
>Dr. Mead,
>
>Please do something about the duplication
>of the TRICKLE-L digest list by each
>applicant's input. It's a great
>discussion but its filling up my email.
>thanks
>
>Robert
>rpolloc@eng.clemson.edu
>

Date: Fri, 1 Dec 1995 00:10:21 -0500
From: MEAD2513@aol.com
Subject: Duplicate mailings (applies only to those having problems)

First of all, I don't understand the problem out there. Second, I would
appreciate it if anyone having a problem with getting their Trickle-L mail,
please address the issue to me personally and not the group as a whole.

Second, if Trickle-L does get too numerous for your patience, it would be
advisable to send:
SET TRICKLE-L MAIL DIGEST

to:

LISTSERV@UNL.EDU

Instead of getting a dozen postings from Trickle-L on a busy day, you get one
email file.

I frankly don't know why the 'duplication of Trickle-L digest' stated
initially is occuring, but have discussed it one on one with the individual
who brought it up.

Thanks for your patience.

Richard Mead
Trickle-L owner/manager

End of Digest
************************

From root@crcnis1.unl.edu Sat Dec 2 21:52 EST 1995
Date: Sat, 2 Dec 1995 15:41:47 -0600
Message-Id: <199512022141.AA01054@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 366

Contents:
Chlorine use in drip systems (MEAD2513@aol.com)

Date: Sat, 2 Dec 1995 16:45:04 -0500
From: MEAD2513@aol.com
Subject: Chlorine use in drip systems

There have been numerous discussions about chlorine use in drip systems on
Trickle-L since the beginning of the list. We've discussed chlorine levels
needed to disinfect the water supply to prevent emitter plugging (Aug '94)
and chlorine in the environment in addition to chlorination alternatives such
as using ozone (Dec '94).

Last week I mentioned that I would be discussing the legalities of injecting
chlorine. But from reading the literature and having discussions with a few
growers in Arizona, I get the impression that chlorine injection is the most
common method to prevent clogging by biological growth (colonial protozoa,
sulfur bacteria, and other mucous organisms) and even to prevent root
intrusion. Hence, Cl use is no big deal and no where is it restricted (please
correct me if I'm wrong).

So, let me shift my emphasis as to what type of chlorine-systems people use.
Gas chlorinators are the cheapest method on a cost per unit Cl than Cl liquid
solutions. However, Cl gas is extremely dangerous, so handling it can be a
problem. Some people use a 6 or 12% solution of sodium hypochlorite (NaOCl)
and inject it into the system as if it were a pesticide or fertilizer. Others
use chlorine tablets such as the ones you find for swimming pools. If anyone
out there is using chlorine in their drip systems, whether it be a normal
procedure or an occasional activity, please post a reply so we can get an
idea as to what is the most accepted or practical Cl-system and why.

Richard Mead
Trickle-L owner/manager
USDA-ARS-WMRL

End of Digest
************************

From root@crcnis1.unl.edu Sun Dec 3 21:53 EST 1995
Date: Sun, 3 Dec 1995 15:42:03 -0600
Message-Id: <199512032142.AA07026@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 367

Contents:
Re: Richard Olson's comments (geoflowr@halcyon.com (Rodney Ruskin))

Date: Sat, 2 Dec 1995 16:08:32 -0800
From: geoflowr@halcyon.com (Rodney Ruskin)
Subject: Re: Richard Olson's comments

At 1:36 AM 11/29/95 -0600, benasher@bgumail.bgu.ac.il wrote:

>Dear Colleagues and Friends
>I have recently received a request from an Israeli (Big, Israeli standards
>) Avocado grower asking me about subsurface drip for Avocado. I have no
>information about it but would like to inquire who has some experience in
>the subject. The information may be direct (to Avocado ) or indirect (
>Related orchards).
>Every piece of information is welcomed but to make it easy for the
>volunteers here are some questions to be answered: ..........
>Jiftah Ben-Asher

Dear Jiftah,

Drip irrigation on avacado has had a poor history in the U.S. Amongst the
very first drip systems installed in the U.S. in about 1968 were several on
avacodos on the hills near San Diego. We had systems severly under-designed
either at best with one single row of drippers or at worst one dripper per
tree! The trees grew pretty well for three years and then could not yield.
The industry switched to micro-sprinklers and the belief that drip does not
work on avacado. Of course there are some successful surface drip systems
on avacodo. As a result I believe that there has been no SDI on avacados.

Metzerplas has excellent subsurface drip technology and I suggest that you
contact them.

Regards,

Rodney.

End of Digest
************************

From root@crcnis1.unl.edu Tue Dec 5 23:58 EST 1995
Date: Tue, 5 Dec 1995 17:44:28 -0600
Message-Id: <199512052344.AA15374@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 368

Contents:
Chlorination of irrigation water ("Sutton, Bruce" <SuttonB@agric.usyd.edu.au>)

Date: Wed, 06 Dec 95 10:19:00 PST
From: "Sutton, Bruce" <SuttonB@agric.usyd.edu.au>
Subject: Chlorination of irrigation water

I would like to revisit the question of chlorination of water as a means of
controlling iron. The water supply I have to plan for is waste water with
problem levels of ferrous iron (about 3 ppm) and high (>100 ppm)
concentrations of ammonium ions. Normally I would follow the traditional
approach of chlorinating to leave some small residual level of free
chlorine, but the reactions of chlorine with ammonia seem to throw up some
complications.

The initial reactions of dissolved chlorine (as hypochlorous acid) with
ammonium ions leads to the formation of monochloramine and dichloramine. In
the extreme, sufficient chlorine will lead to the conversion of ammonium
ions to nitrogen gas. In waste-water treatment, this is known as breakpoint
chlorination and is one method of stripping ammonia from water. This is
described in detail in "Process Design Manual for Nitrogen Control", US EPA
Technology Transfer, 1975.

Chloramines interfere to some extent with the determination of free chlorine
concentrations, especially with the normal DPD colourimetric reaction
(Derrigan et al (1975). Comparison of free and total chlorine measurement
methods in municipal wastewaters. Water Environment Research 65:205.).

Which, at last, leads me to my questions.

1. Do chloramines, as well as free chlorine, work effectively in
precipitating ferric iron salts?

2. With irrigation water enriched with ammonium ions, either from fertiliser
or effluent, can we achieve the desired results of iron precipitation and
inhibition of algal and bacterial growth without titrating all the ammonia
away? (The chloramines are much weaker disinfectants than free chlorine.)

3. Given the above, how useful are the standard colourimetric test kits we
normally use for free chlorine estimation?

4. Are there any other dependable methods for dealing with iron as
effectively as chlorine should, but which avoid the interactions with
dissolved ammonium ions?

Thanks for your thoughts.

Bruce Sutton,
Senior Lecturer,
Department of Crop Sciences,
University of Sydney, NSW 2006,
Australia.
Phone: +61-2-351-2050
Fax: +61-2-351-4172
email: suttonb@agric.usyd.edu.au

End of Digest
************************

From root@crcnis1.unl.edu Wed Dec 6 23:58 EST 1995
Date: Wed, 6 Dec 1995 17:44:28 -0600
Message-Id: <199512062358.ab4el@ab4el.com>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 369 was lost

TRICKLE-L digest 369 was lost

TRICKLE-L digest 370 was lost

TRICKLE-L digest 371 was lost

TRICKLE-L digest 372 was lost

TRICKLE-L digest 373 was lost

TRICKLE-L digest 374 was lost

TRICKLE-L digest 375 was lost

TRICKLE-L digest 376 was lost

TRICKLE-L digest 377 was lost

TRICKLE-L digest 378 was lost

From root@crcnis1.unl.edu Wed Dec 20 20:15 EST 1995
Date: Tue, 19 Dec 1995 10:15:17 -0600
Message-Id: <199512191615.AA14197@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 379

Contents:
Re: Copy of: Information on Sentek EnviroSCAN (GrapeGrowr@aol.com)
Re: Mycorrhial Fungi (GrapeGrowr@aol.com)
Re: Tensiometer rehash (FLamm@oznet.ksu.edu (Freddie Lamm))
Hi there (cfb1@cornell.edu (Charlie Brush))

Date: Mon, 18 Dec 1995 10:42:19 -0500
From: GrapeGrowr@aol.com
Subject: Re: Copy of: Information on Sentek EnviroSCAN

Please send me info on this to:
Robert Carian
PO Box 1088
Coachella, CA 92236
619-398-1144

Date: Mon, 18 Dec 1995 10:43:36 -0500
From: GrapeGrowr@aol.com
Subject: Re: Mycorrhial Fungi

Is this fungi a good guy and have you heard of commercial applications of it
being a success?

Date: 18 Dec 95 15:10:20 CST
From: FLamm@oznet.ksu.edu (Freddie Lamm)
Subject: Re: Tensiometer rehash

Suffice it to say tensiometers do behave differently in different
soil types.

Soil matric potentials (which is what tensiometers measure,
***not*** plant water stress) might be identical for two tensiometers
on two soil types, but their meaning could be very different.
Tensiometers also measure at a ***POINT***, while the crop may be
seeing a very different ***integrated*** soil water potential (due to
different soil water conditions at different soil layers, depending on
climatic demand, and depending on root distribution, etc.).
Generalized statements are dangerous. Tensiometers are a tool that
do give some information about a physical parameter related to the
energy required for water withdrawal. However, there is a lot of
integration going on in the crop. AND for deep, extensive crop root
systems on deep heterogenous soils with good available water holding
capacity, the integration may **swamp** out the meaning of the
tensiometer reading. Remember, it is possible to weigh a flea on an
elephant with very accurate scales, but it may be easier to weigh it
alone on a smaller scale.

Craig Storlie said he has never seen any significant lag times or
problems with partial contact. However he goes on to point out
ranges of 5-30 cb. While these are appropriate for trigger points on
sands, they are still higher than the typical field capacity of 33
cb. Tensiometers when used near the break point of 70-80 cb do have
some lag time and poor soil contact can increase this lag time on
some soils. De-aired water or an early 1st refill is useful on
longer tensiometers (4-5 ft) to prevent the vacuum breaking
prematurely. Why use such long tensiometers??? Why use close to the
breakpoint???? Because tensiomters are **also used** for hydraulic
gradient studies in this case near the bottom of the root zone. Last
week, I said I did not use tensiometers for irrigation scheduling on
our deep silt loam soils, but I have used them for hydraulic
gradient studies (in cooperation with a soil scientist).

For those that mentioned the negatives of mercury-based
tensiometers, presumedly needing to get very precise research quality
measurements, you might look into the pressure transducer-type system
marketed by Soil Measurement Systems, (SMS), 7344 N. Oracle Road,
Suite 170, Tucson, AZ 85704, USA, Phone 602-742-4471 or FAX
602-797-0356. I'm not sure what all they market, but they do market
a hand-held transducer you can take from one tensiometer to another.
The tensiometer is a piece of 1/2 inch PVC (Any length within
practical tensiometer range, We have used to 5.5 ft) with a ceramic
cup cemented to the bottom and a medicine bottle septum on top. The
ones I have used have been fabricated in a campus workshop by
students with the cup and septums purchased from SMS. I believe the
soil scientist I have worked with says they end up costing about $10
each (labor included??). The Tensimeter (pressure transducer) is
around $2000.

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: Tue, 19 Dec 1995 10:18:50 -0800
From: cfb1@cornell.edu (Charlie Brush)
Subject: Hi there

Dale -

Hi there. Remember me? I managed Mark Freeman's project for the Energy
Commission. I left the CEC in 1992 and came up to Cornell to do a PhD in
Ag Engineering. I expect to finish in the next 6-8 months.Then ... ?

How are things going for you? I hope you and your family are well.

Take care,

Charlie Brush

End of Digest
************************

From root@crcnis1.unl.edu Wed Dec 20 19:55 EST 1995
Date: Wed, 20 Dec 1995 10:16:12 -0600
Message-Id: <199512201616.AA03047@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 380

Contents:
Re: Tensiometer transducer Europe (stein@wiz.uni-kassel.de (Thomas-M. Stein))
Unsubscribe Trickle (MIPerez@aol.com)
Re: scheduling discussion on tensiometers (milligan@smartdocs.com (Milligan/Roatcap))
Re: Tensiometer transducer Europe (pdspyke@gate.net)

Date: Tue, 19 Dec 1995 17:37:27 +0100 (MEZ)
From: stein@wiz.uni-kassel.de (Thomas-M. Stein)
Subject: Re: Tensiometer transducer Europe

For those interested in Tensimeters (pressure transducers)
and who are living in or closer to Europe:

According to Freddie Lamm (FLamm@oznet.ksu.edu):

[text deleted]

>For those that mentioned the negatives of mercury-based
>tensiometers, presumedly needing to get very precise research quality
>measurements, you might look into the pressure transducer-type system
>marketed by Soil Measurement Systems, (SMS), 7344 N. Oracle Road,
>Suite 170, Tucson, AZ 85704, USA, Phone 602-742-4471 or FAX
>602-797-0356. I'm not sure what all they market, but they do market
>a hand-held transducer you can take from one tensiometer to another.
>The tensiometer is a piece of 1/2 inch PVC (Any length within
>practical tensiometer range, We have used to 5.5 ft) with a ceramic
>cup cemented to the bottom and a medicine bottle septum on top.

[text deleted]

There is a similar very precise (1 mbar sensitivity) hand-held transducer
with a movable eccentric needle head (which prevents using the same area for
puncturing the septum stopper). This TENSIMETER is produced by a Swiss
company. We have used it extensively for our research without any problems.
There is also a model called TENSICODER with a built-in solid state memory
to store the readings.

The price for the standard TENSIMETER is approximately 2700 sFr. (Swiss Francs).

Address:
Dr.von Ballmoos AG
Toedistrasse 44
CH - 8812 Horgen
Switzerland

Tel.: 0 [041] 1 725 29 41
Fax : 0 [041] 1 725 09 07

Regards

Thomas
______________________________________________________________________________

Thomas-M. Stein
University of Kassel (FB11) Phone : (+49)-5542-98-1632
Dep. of Rural Engineering and Fax : (+49)-5542-98-1588
Natural Resource Protection Email : stein@wiz.uni-kassel.de
Nordbahnhofstr. 1a WWW : http://www.wiz.uni-kassel.de/kww/
D-37213 Witzenhausen, GERMANY List owner: IRRIGATION-L@listserv.gmd.de
______________________________________________________________________________

Date: Tue, 19 Dec 1995 17:41:58 -0500
From: MIPerez@aol.com
Subject: Unsubscribe Trickle

Unsubscribe trickle

Date: Tue, 19 Dec 1995 19:15:55 -0800
From: milligan@smartdocs.com (Milligan/Roatcap)
Subject: Re: scheduling discussion on tensiometers

>Trickle-l and Milligan:
>
>I sounds like you know a lot about what you are doing! Freddie Lamm's
>(FLamm) advice is pretty much on target about tensiometers. Most any
>Civil Engineering or agricultural science laboratory should be able to
>run a particle size analysis on your different soil types and tell you
>how much sand, silt, and clay each had. This information is important
>in classification (loamy sand versus sandy loam etc.). One point that
>Freddie didn't mention that I have found important in using
>tensiometers is daily graphing of measurements. This let's me see
>trends I may miss in tables of observations.

You know, I have the SCS soil survey with it's classifications of my various
soil types. I use the data on moisture holding capacity for my ET water
budgeting calculations. Are there other facts in that book that might help
me understand how the irrometers would behave?

>In addition, you didn't mention exactly how you irrigate (dripper,
>mini-spray, spitter, rotator, etc.), where the applicators were
>located in relation to the tree, or where the tensiometers were
>located depth and space from tree and applicator. All of these may
>affect the tensiometer reading (but it should be somewhat relative).

I have switch instruments at the troubled sandy sites, reset,de-aired and
watched for water loss with no big change.

I use T-Tape, their "Cane Special," knifed about 3" subsurface. Deeper than
that and my pines' roots tend to grow on two sides of the tape and squeeze
it off like a pair of hemostats would. Emitters are on 2' centers and about
eight hours of operation can (on the soil's surface) give the impression of
a 18" wide wetted strip. I locate my 12" and 24" tensios 12 inches from the
emitters. EVEN THEN, I can play hell getting the wetting to the tip of the
instrument in some areas. In such cases it can require MUCH more water than
the calculated ET suggests to reach the 12" instrument's tip. If needed I
fudge and dig a shallow resevoir to favor the direction of the tensio. This
practice worries me some, but at least I get some idea of how fast the roots
are drying the area in the immediate vicinity of the instrument.

>With water costs of $400/AF (that's about 10 times our pumping cost
>here and would make irrigated wheat a LITTLE less profitable), you
>need to be concerned about all losses, but particularly deep
>percolation.

Yup, a big issue for me.

>In this respect, a few monitoring stations with deep
>tensiometers (or other soil water sensors) at about the bottom of the
>root zone could indicate if much water is moving downward. Also at
>this depth the movement should be more one-dimensional less affected
>by spacing and/or site. Soil water measurements (either tension or
>water content) will not tell you how much water may be moving but
>merely indicate how strong the gradient for movement may be.
>........text deleted.................

>Terry Howell

Thanks for the input, Terry,

Merry Christmas,
Mike

Date: Wed, 20 Dec 1995 08:44:31 -0500
From: pdspyke@gate.net
Subject: Re: Tensiometer transducer Europe

>There is a similar very precise (1 mbar sensitivity) hand-held transducer
>with a movable eccentric needle head (which prevents using the same area for
>puncturing the septum stopper). This TENSIMETER is produced by a Swiss
>company. We have used it extensively for our research without any problems.
>There is also a model called TENSICODER with a built-in solid state memory
>to store the readings.

Peter Spyke replies here:

Thomas, I am very interested in the TENSICODER. Does Dr. von Ballmoos
have an e-mail address? And, is the TENSICODER available anywhere in
the US?

>
>The price for the standard TENSIMETER is approximately 2700 sFr. (Swiss
Francs).
>
>Address:
>Dr.von Ballmoos AG
>Toedistrasse 44
>CH - 8812 Horgen
>Switzerland
>
>Tel.: 0 [041] 1 725 29 41
>Fax : 0 [041] 1 725 09 07
>
>Regards
>
>Thomas

Thank you for this information, Thomas!

Pete Spyke

>

End of Digest
************************

From root@crcnis1.unl.edu Thu Dec 21 16:28 EST 1995
Date: Thu, 21 Dec 1995 10:16:31 -0600
Message-Id: <199512211616.AA18637@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 381

Contents:
Re: Tensiometer transducer Europe (jp@unlinfo.unl.edu (jerome pier))
Long Distance for a Cause (cnotes@cnotes.com (CNI))
Re: Tensiometer transducer Europe(2) (stein@wiz.uni-kassel.de (Thomas-M. Stein))
Re: Tensiometer transducer Europe(2) (PHLASH79@aol.com)

Date: Wed, 20 Dec 1995 12:39:18 -0600 (CST)
From: jp@unlinfo.unl.edu (jerome pier)
Subject: Re: Tensiometer transducer Europe

> Peter Spyke replies here:
>
> Thomas, I am very interested in the TENSICODER. Does Dr. von Ballmoos
> have an e-mail address? And, is the TENSICODER available anywhere in
> the US?
>
The Two devices are available from Soil Measurements in
Tucson Arizona. Here's the contact info:

Phone: (520) 742-4471
FAX: (520) 544-2192
email: soilmeasure@mcimail.com

As mentioned in a previous email, there is also a smaller
device which measures in kPa (~cbars) for about $800. They also
sell tensiometers and the rubber septums which go with them. The
per unit price goes down with this type of system as the number
of tensiometers increases greatly.

Sincerely,

Jerome Pier
Soil Scientist/Agronomist
Netafim Irrigation, Inc.
jpier@qnis.net

Date: Wed, 20 Dec 1995 15:07:09 -0500
From: cnotes@cnotes.com (CNI)
Subject: Long Distance for a Cause

My apologies for my recent "half-post." As many of you alerted me, I
forgot to include my .sig file (which, hopefully, appears below). For
those of you who did not welcome my post for its advertising content, I
shall refrain from such posts in the future. Again, if you're interested
in saving up to 60% on your long distance usage for either your
organization or residence, please see below for details.

Happy holidays,

Michael Corso
CNI Telecom

+ Join CNI Long Distance - the only FLAT RATE long
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Date: Wed, 20 Dec 1995 22:56:52 +0100 (MEZ)
From: stein@wiz.uni-kassel.de (Thomas-M. Stein)
Subject: Re: Tensiometer transducer Europe(2)

Pete,

as far as I know they don't have email but they did responde very
quickly on my faxes. By the way, the descriptions are in English and they
seem to sell abroad as well (at least we have directly purchased it from
them).

According to pdspyke@gate.net:
>Thomas, I am very interested in the TENSICODER. Does Dr. von Ballmoos
>have an e-mail address? And, is the TENSICODER available anywhere in
>the US?
>
>>
>>The price for the standard TENSIMETER is approximately 2700 sFr. (Swiss
>Francs).
>>
>>Address:
>>Dr.von Ballmoos AG
>>Toedistrasse 44
>>CH - 8812 Horgen
>>Switzerland
>>
>>Tel.: 0 [041] 1 725 29 41
>>Fax : 0 [041] 1 725 09 07
>>
Best regards

Thomas Stein

Date: Thu, 21 Dec 1995 03:53:02 -0500
From: PHLASH79@aol.com
Subject: Re: Tensiometer transducer Europe(2)

I have read with interest the information on irrigation scheduling. Another
method not described or discussed in this forum though known to a few of the
respondees is that of "heat dissipation" for precise measurement of soil
matric potential. This approach uses a stable matrix with a wide range of
pore sizes (such as ceramic) to model all soils. The concept relies on the
idea that water conducts heat more efficiently than air. The sensor itself
measures "heat dissipation" from a point heat source. In soil or in our
model matrix we have void spaces which possess air-water ratios ranging from
almost all air in dry soils to all water in saturated soils. The sensor
provides a soil temperature as the base reading. The sensor is then heated
for a fixed period of time. At the end of the heating period the temperature
is measured again. The resulting change in temperature can be directly
related to soil matric potential when calibrated using the pressure plate
approach. This sensor has been shown to work in both research and actual
application.

Though the sensor does provide a point measurement theoretically independent
of soil type, I agree that the coupling of the sensor output with some type
of water (class A pan) or energy balance (weather station) approach provides
an adequate irrigation scheduling tool for the ag or horticultural sector.
This approach requires automation of both the data collection and the number
crunching to arrive at useable daily information. Most approaches which
require the user to inspect and log the information manually each day are
doomed to failure as evidenced by the large number of tensiometers residing
in sheds and store rooms.

Anyone interested in more information on scheduling, commercial sources for
datalogging, soil matric potential sensors, class A pans, or subsurface drip
can contact me directly at Landmark7@aol.com. As an adjunct to this,
Landmark Irrigation will offer to anyone on this list irrigation parts and
equipment at below wholesale prices. Landmark Irrigation is a dealer or
distributor for almost all irrigation manufacturers.

If I can be of assistance to either the researchers or end users please let
me know.

Best Regards,
Jim Phene
Landmark7@Aol.com

End of Digest
************************

From root@crcnis1.unl.edu Fri Dec 22 16:31 EST 1995
Date: Fri, 22 Dec 1995 10:18:31 -0600
Message-Id: <199512221618.AA05633@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 382

Contents:
Re: Tensiometer transducer Europe(2) (Richard Funt <funt@agvax2.ag.ohio-state.edu>)
UNSUBSCRIBE TRICKLE (ELSWHRE@aol.com)
unsubscribe trickle (ELSWHRE@aol.com)
Re: Tensiometers #1 (milligan@smartdocs.com (Milligan/Roatcap))
New member introductory answers (Philippe Revol <Philippe.Revol@cemagref.fr>)

Date: Thu, 21 Dec 1995 13:42:37 +500
From: Richard Funt <funt@agvax2.ag.ohio-state.edu>
Subject: Re: Tensiometer transducer Europe(2)

Date: Thu, 21 Dec 1995 14:55:37 -0500
From: ELSWHRE@aol.com
Subject: UNSUBSCRIBE TRICKLE

Unsubscribe trickle

Date: Thu, 21 Dec 1995 15:22:04 -0500
From: ELSWHRE@aol.com
Subject: unsubscribe trickle

Unsubscribe trickle

Date: Thu, 21 Dec 1995 18:46:42 -0800
From: milligan@smartdocs.com (Milligan/Roatcap)
Subject: Re: Tensiometers #1

Hi Craig,

Sorry to take so long responding to your interesting post. December is
payday for Christmas tree growers, and I'm running in such fevered, ever
shrinking circles that I fear I may need a proctologist to find myself.

> Mike Milligan described an interesting problem. Given similar
>water withdrawal rates (ie., similar plant type, growth stage,
>health; ie., plants using water at the same rate in the sandy and
>finer-textured areas) tension should jump quicker in the sandy zone
>and should rise well above 30 cb. Are you sure the sandy zone
>tensiometer did not break tension and drop to 30?

Yeah, I've checked it several ways, including placing a second, new
instrument a short distance away at the same depth and same distance from an
emitter, etc.

>After breaking
>tension, I've seen tensiometers sit at random tension levels
>anywhere between 0-85 cb. I can't imagine what else can be
>happening. Has it happened more than once? On more than one
>tensiometer (vacuum gages do go bad, yearly calibration is
>important)? In more than one location?

I had the problem on a sandy loam with a block of five-year-old trees. I
tried different irrometers in three different areas with similar results. I
could ultimately water them down to less than 10 cbars, but they'd seldom go
much above 25 or so cbars no matter (I guess) how dry they got. I have
three-year-olds on the same soil (at least according to the old SCS soil
survey map) and the irrometers perform very well. At the other end of the
same soil field I have one-year-olds that show a very limited range of
drying, but they have such a limited root system at this point I am not
surprised.

Thanks for your interest and happty holidays,
Mike Milligan

Date: Fri, 22 Dec 1995 12:56:01 -0500
From: Philippe Revol <Philippe.Revol@cemagref.fr>
Subject: New member introductory answers

I am not exactly a new subscriber for I have been connected for three month
during a stay in HortResearch, Palmerston North, New Zealand, with Brent
Clothier and the Environment Group. Coming back home with a less bad English
(?) it's time for me to answer the general introductory questions.

1) Briefly, what is your affiliation with trickle/drip irrigation?
I am a scientist working in Montpellier (South of France) at the French
Institute of Agricultural and Environmental Engineering Research (Cemagref).
I have been working on DI/SDI since 1988, on measuring and modelling the
soil water movement under drippers, and, along with extension services, on
the growers practical problems.

2) What crops or plants do you use drip irrigation on?
I have been working on peach, asparagus, tomato, maize, sorghum, etc.

3) If using subsurface drip irrigation, what is the average depth of
placement of the drip lateral? From 40 to 15 cm.

4) What problems have you encountered with drip irrigation?
The two main problems in France are emitters clogging, with surface water,
and growers difficulties in irrigation control.

5) Fertigation is a real advantage of drip irrigation. What form of N, P
and K have you been trying and to what success? Yes except when there is a
need to fertilize and no need to irrigate (for ex., possible cases on
vegetables in spring.)

6) Have you experienced a reduction in fertilizer and/or water use?
Despite literature statements, there is no evidence in France that
irrigation needs for any crop are different between sprinkler and drip
irrigation (both well controlled).

7) Do you have water quality problems? If so, how do you tackle the
situation? See 4), a study on filters performances is currently conducted.

8) How frequent do you irrigate? Many times a day or just one long
session per day or several days?
The practice here is from many times a day to a session per week or two
weeks. However most cases are close to a couple of times a day, depending on
the fact the switch is manual or no.

9) Do you have rodent damage? If so, how do you control the problem?
Yes, and sometimes hunters (vandalism) damage too !

10) Are you pleased with the uniformity of your system or systems? Were
they designed correctly?
Yes, when there is also no clogging. Almost all emitters on the French
market are tested in the Cemagref Laboratory in Aix en Provence (uniformity,
clogging resistance, hydraulic characteristics).

11) How did you find out about our mailing list?
I found this list at the 5th International Microirrigation Congress in
Orlando last April.
____________________________________________

Philippe Revol
Cemagref, BP 5095
34033 Montpellier Cedex 1, France
Tel (33) 67 04 63 00 ; Fax (33) 67 63 57 95
E-mail Philippe.Revol@cemagref.fr
____________________________________________

End of Digest
************************

From root@crcnis1.unl.edu Fri Dec 29 00:47 EST 1995
Date: Thu, 28 Dec 1995 18:32:54 -0600
Message-Id: <199512290032.AA18860@crcnis1.unl.edu>
Errors-To: rmead@asrr.arsusda.gov
Reply-To: <trickle-l@unl.edu>
To: Multiple recipients of list <trickle-l@unl.edu>
Subject: TRICKLE-L digest 383

Contents:
GROUNDWATER discussion group (dowser@sover.net (Kenneth E. Bannister))

Date: Thu, 28 Dec 1995 19:34:48 -0500
From: dowser@sover.net (Kenneth E. Bannister)
Subject: GROUNDWATER discussion group

ANNOUNCING: GROUNDWATER

A New Internet Mailing List.

Please join our global discussion group on groundwater.

To subscribe to GROUNDWATER send e-mail to:

majordomo@ias.champlain.edu

In the body of the e-mail type the command:

subscribe GROUNDWATER

To send mail to the list after you have subscribed, address the
mail to:

GROUNDWATER@ias.champlain.edu

WE hope to see you on our list.

Kenneth E. Bannister
List-Owner
GROUNDWATER

End of Digest
************************

Prepared by Steve Modena, AB4EL.
Comments and suggestions to: modena@SunSITE.unc.edu