Archive TRICKLE-L: file log9408, part 1/1, size 69154 bytes:

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Richard,
Any reason for not using bleach. This seems like a simpler technique
and is used for water wells etc. The trick is to get the concentration
about right. I also used the clorine tablets for swimming pools with a
timed trickle pump to feed my house water. This was done to help remove the
iron in the water.

Jeff McSpadden
jeff@mpd.tandem.com
> From root@crcnis1.unl.edu Sun Jul 31 22:07:58 1994
> Date: Sun, 31 Jul 1994 22:00:31 -0500
> Originator: trickle-l@unl.edu
> Reply-To: <trickle-l@unl.edu>
> Sender: trickle-l@unl.edu
> Version: 5.5 -- Copyright (c) 1991/92, Anastasios Kotsikonas
> From: MEAD2513@aol.com
> To: Multiple recipients of list <trickle-l@unl.edu>
> Subject: water treatment
> Content-Length: 470
>
> Does anybody out there know about various ways to chlorinate water for algea
> and fungus in the drip line? Chlorine gas is the normal way, yet I've been
> hearing about a safer way using NaCl salt water and using electrolysis to
> split the Cl away from the Na. If this is true, what do the former ions form
> after the split?
> Also, I would like comments on what Cl concentration one uses
> and what pH is appropriate for 100 % dissolution.
>
> Sincerely,
>
> Richard Mead
> List owner
>
>

For those of you just dying to learn about Chlorine....the topic I tried to
initiate several days ago, I've done some research for everybody to share.

I have found through various sources that 1.0 ppm of free residual chlorine
is sufficient to kill almost all bacteria. This level is that which is left
after the chlorine has been injected. If chlorine reacts with sulfides, iron
or slime bacteria, enough must be injected into the system to meet the
required reactions to still leave 1.0 ppm Chlorine.

Constant, automated, chlorination is often recommended where the farm lacks
personel with specific skills needed to safely handle chlorination on an
intermittent basis. Intermittent treatments, including shock treatments where
clogging has already occured, require that some math calculations.

If you desire intermittent chlorination, a 10 to 20 ppm range is needed for a
period of 30 to 60 minutes.

When emitters are partially plugged or clogged by organic matter,
superchlorination may be needed to clear the system. Superchlorination
treatment ranges from 20 to 50 ppm Cl. The highly concentrated solution
should stay within the system for 24 hours with the system OFF. At the end of
this period, flushing should be accomplished through the mains, submains and
laterals.

As one subscriber already suggested, test kits for swimming pools are
available to measure "total" chlorine or "free" chlorine.

Chlorine gas and pellets are known methods of introducing Cl into the
irrigation system, yet I would strongly suggest acidifying the system to
allow more dissolution of Cl. Your wasting time and $ if the pH is not
lowered below 6.5 at least temporarily during chlorination.

Please respond with comments or questions if this topic tweaks your interest.
I quess nobody knew about the NaCl solution with electrolysis question.

Sincerely,

Richard Mead
List Owner

I am just beginning the planning process for rewriting the chapter on:
"Design and Operation of Trickle Systems" in the ASAE Monograph--Design
and Operation of Farm Irrigation Systems (1980). At this point I am
trying to develop a fairly detailed outline of topics to be covered (not
including hydraulics). I would appreciate any thoughts and/or
suggestions on what you think should be included (and why) as well as what you think should be
changed from the previous chapter (and why). I need to develop this
outline by October 1.

Thank you in advance for any input you may have.

Fellow Readers!!

I am working on an infiltration problem on tilled soils and sincerely believe
an infiltration simulation model will ease my task. Is there anyone out there
who can help direct me where to get such a package or a source code for any of
the models whose results have been published? While the publications
describe the model(s) and report the governing equations, I hate to start
re-inventing the wheel.

My sincere thanks.

Neba Ambe
Dept. Agric. Engr.
Michigan State Univ.

Hi Neba, SIMPOTATO is available by ftp from ftp.tricity.wsu.edu in
directory simpotato, it is compressed with lha.exe, also in that
directory. let me know about any problems. Tom

Tom Hodges Cropping Systems Modeler ___ ___
USDA-ARS / \_/ \
Rt. 2, Box 2953-A Telephone: 509-786-9207 | |
Prosser, WA 99350 Fax: 509-786-4635 \______/^\/
USA potato tuber
============= thodges@beta.tricity.wsu.edu ========================
...photosynthesis makes the world go around... Mr. Potato Head

On Thu, 4 Aug 1994, Neba Michael Ambe wrote:

> Fellow Readers!!
>
> I am working on an infiltration problem on tilled soils and sincerely believe
> an infiltration simulation model will ease my task. Is there anyone out there
> who can help direct me where to get such a package or a source code for any of
> the models whose results have been published? While the publications
> describe the model(s) and report the governing equations, I hate to start
> re-inventing the wheel.
>
> My sincere thanks.
>
> Neba Ambe
> Dept. Agric. Engr.
> Michigan State Univ.
>
>
>
>

To: Neba and ALL

Could you describe the desired parameters for an infiltration model. What
would the dependant and independant variables be, and how would you handle
different soil types and differing soil type interfaces?

I would love to be able to roughly predict the infiltration rates (easy) and
then predict the resulting patterns of moisture distribution (hard). I would
like to be able to predict how much the plants would be drawing from the just
applied water, and how much the plants would be drawing from water that has
been in the soil long enough to reach nutrient equilibrium.

I would hope such a model could help me predict, for example, how much of my
sub-surface drip applied Potassium Sulfate actually would be absorbed by the
plant before it is tied up in the soil. Once our soil grabs K, it releases
it very slowly. Are these kinds of predictions possible yet?

Craig Thompson, grape grower, California

> To: Neba and ALL
>
> Could you describe the desired parameters for an infiltration model. What
> would the dependant and independant variables be, and how would you handle
> different soil types and differing soil type interfaces?

Most of the models I have come across have diffusivity, hydraulic conductivity
and (sorptivity in some cases) as independent variables and infiltration rate
as the dependent variable if the infiltration model makes use of Darcy's law.
The infiltration depth and time are of course important. The lower and upper
limits of the soil water each soil layer can hold as well as the initial soil
water content are crtical as they determine
when the soil is saturated and further infiltration is hindered or drainage is
accelerated.

For different soil types I would imagine the behaviour of the model will depend
on the particular soil's physical properties. This means the model will have
to be initialized with parameter values that are specific to that soil.

With regards to differing soil type interfaces, I suppose one could use a
distributed delay approach. Consider the Ls to be layers with water
L1 _________________________ theta 1, v1

L2 ------------------------- theta 2, v2

L3 _________________________ theta 3, v3
contents "theta" and flow rates "v". The distance L1-L2 is a delay storage
whose theta(1) is determined by the incoming flow rate v1 and the out going
flow rate v2. L1-L2 and L2-L3 will each have unique parameter values.

The flowrates Vi for each layer can be calculated, from Darcy's equation for
example, adjusting for for the distance between the centers of the adjacent
layers.

The water contents for each layer as follows:
d-theta 1 = ((v1-v2)/dZ)*dt, where dZ is the layer thickness
dt is time increment
d-theta 2 = v2-v3

> I would love to be able to roughly predict the infiltration rates (easy) and
> then predict the resulting patterns of moisture distribution (hard). I would
> like to be able to predict how much the plants would be drawing from the just
> applied water, and how much the plants would be drawing from water that has
> been in the soil long enough to reach nutrient equilibrium.

I have seen two publications where the soil moisture distribution has been
successfully predicted. But the problem is you cannot lay hands on the source
code or the program that you could modify to meet your needs. If you are
interested in them, I can send you the references or the copies. Just let me
know.

> I would hope such a model could help me predict, for example, how much of my
> sub-surface drip applied Potassium Sulfate actually would be absorbed by the
> plant before it is tied up in the soil. Once our soil grabs K, it releases
> it very slowly. Are these kinds of predictions possible yet?

Sounds like getting a "K-release" model to interact with an infiltration model.
I have not come across anything like that as yet. But I think it's possible.
One might actuaaly be looking at a difussion model.

If you have further suggestions I'll be glad to listen to them.
Thanks.

neba

> Craig Thompson, grape grower, California
>
>

For those of you that have subscribed and have not received the welcome
information, please write to me at: MEAD2513@AOL.COM if you wish to obtain
the welcome information and small survey.
Thank you!

Sincerely,

Richard Mead - List owner

p.s. If you wish to view who else is on the list, simply type:
"rev trickle-l" (without the quotes) to the following
address....listserv@unl.edu

within minutes, a list, in chronological order of subscription placement will
appear. At current standing, we have 89 members.

rev trickle-l

rev trickle-l

I would appreciate the message. Also I have received two messages
containing only the following " rev trickle-l " I have not the foggiest
what that means. Can you help me out. Thanks

Allan

On Sat, 13 Aug 1994, Allan Hall wrote:

> I would appreciate the message. Also I have received two messages
> containing only the following " rev trickle-l " I have not the foggiest
> what that means. Can you help me out. Thanks
>

Those messages are the results of the posters being unable to comply
with short, concise instructions....

the "rev trickle-l" massage should have been sent to LISTSERV@unl.edu,
than than to TRICKLE-L@unl.edu....

Steve Modena

>Those messages are the results of the posters being unable to >comply
>with short, concise instructions....

>the "rev trickle-l" massage should have been sent to >LISTSERV@unl.edu,
>than than to TRICKLE-L@unl.edu....

I, for one, plead guilty! I did not catch on to the different address. The
instructions came from trickle-l@unl.edu ... and using the automatic reply
function sent the list server command to be distributed to the rest of the
participants ... instead of sending back a list of particiants to just me.

O.K. then ... list server commands go to LISTSERV@unl.edu,
discussion postings go to Trickle-L@unl.edu

Now it seems simple enough ... my digital irrigation timers were supposed to
be simple too ... but that's another topic.

Craig Thompson,
Grape grower
Lodi, CA

Dear new members,
My apologies for telling you to send "rev trickle-l" to the wrong address.
Again, it should have been sent to "listserv@unl.edu" instead of
"trickle-l@unl.edu"

A thousand pardons!!!

Richard Mead
List owner

Well once again, the mail has slowed to less than a trickle (no pun
intended). I always feel obligated to get conversations going again.

As of today (Aug 14) we have 91 members. This is a good number, but I am sure
it will grow. I have noticed that we have a diverse membership which is all
the better. Let me break the ice (again) and ask any of you what your
interest is in trickle or drip irrigation? Are you associated with research,
farm, or industry ? What kind of information do you desire on this service?
Are you satisfied so far? I'll try to appease as many people as possible if
only I got input.

Just to let you know, Dave Zoldoske, director of C.I.T. (Center of Irrigation
Technology) has let me know that he is going to start a similar email list
and will advertise our list (as long as we advertise his). So as soon as he
gets everything together, I'll let everyone on this service know what is
going on with C.I.T.'s mail list.

Once again, let's not be shy. There is so much out there we need to learn
about drip irrigation.
Let the conversations begin!!

Sincerely yours,

Richard M. Mead
List owner

DR. MEAD, WHAT IS YOUR BACKGROUND AND HOW DID YOU ACCOMPLISH SETTING UP THIS
ON-LINE CONVERSATION?

I GREW UP ON AN IOWA FARM WHICH DID NOT NEED IRRIGATION. MY FIRST EXPERIENCE
WITH IRRIGATION AND IN PARTICULAR DRIP IRRIGATION WAS IN ISRAEL ON AN
INTERNATIONAL WORK EXPERIENCE PROGRAM THROUGH THE FUTURE FARMERS OF AMERICA,
NOW KNOWN SIMPLY AS FFA. TODAY I OWN AN AGRICULTURAL PUBLIC RELATIONS AND
MARKETING SERVICES CONSULTING COMPANY. MY MOST RECENT EXPERIENCE WITH DRIP
IRRIGATION WAS ONCE AGAIN RELATED TO ISRAELI TECHNOLOGY. OUR FIRM, CONTRACTED
BY THE ISRAELI TRADE COMMISSION, PROMOTED A NATIONAL TRADESHOW CALLED
"AGRITECH'93" IN THE U.S. AGRICULTURAL PRESS TO ENCOURAGE INTERESTED
INDIVIDUALS AND COMPANY REPRESENTATIVES TO ATTEND. WE WORKED WITH THE EDITORS
OF SEVERAL MAJOR PUBLICATIONS TO DEVELOP STORIES AROUND THE USE OF ISRAELI
DRIP IRRIGATION TECHNOLOGY. ONE OF THE MOST INTERESTING, I THOUGHT, WAS THE
USE OF DRIP IRRIGATION TECHNOLOGY IN A GREENHOUSE MOSHAV COMPLEX IN THE GAZA
STRIP WHICH WAS PRODUCING, PACKAGING AND EXPORTING CHERRY TOMATOES WHICH WERE
DRIP IRRIGATED WITH SALT WATER.

IS THIS CURRENTLY BEING DONE ANYWHERE ELSE IN THE WORLD? WHO WOULD YOU
SUGGEST I CONTACT TO FIND OUT?

THIS LEADS TO A RELATED INTEREST WHICH IS THE APPLICATION OF GENETIC
ENGINEERING SALT-TOLERANCE AND DROUGHT TOLERANCE INTO PLANTS NOW CURRENTLY
BEING GROWN UNDER IRRIGATION. WHAT WOULD THE POTENTIAL FOR INCREASED
VEGETABLE/FOOD PRODUCTION BE IF WE WERE ABLE TO USE HALF THE WATER WE NOW USE
UNDER DRIP IRRIGATION SYSTEMS...AND SALT WATER AT THAT...TO PRODUCE THE SAME
AMOUNT OF PRODUCT?

AN AG BIOTECH FRIEND TODAY TOLD ME THE UNIVERSITY OF ARIZONA HAS PATENTED
SUCH A GENE WHICH COULD BE INSERTED INTO VEGETABLES OR FLOWERS. IT SUPPOSEDLY
ALSO PROLONGS THE SHELF-LIFE. DOES ANYONE IN THIS GROUP KNOW MORE ABOUT THAT,
OR SIMILAR PROJECTS, ANYWERE IN THE WORLD?

I'LL BE QUITE CURIOUS TO SEE WHAT KIND OF RESPONSES I MIGHT GET BACK TO THESE
QUESTIONS. THANKS IN ADVANCE FOR YOUR HELP.

P.S. HOW WOULD I GO ABOUT SETTING UP A BBS FOR AGRICULTURAL WRITERS AROUND
THE WORLD? WHO MIGHT I CONTACT ON INTERNET TO DO THIS?

Hello All,
My name is Leslie Roy and I have been raising hops (used in beer) and
apples under buried drip for 7 years. I have messing around with drip in
general for almost 15 years.
I have worked alot with Dr Phene from UC Fresno. He has recently
retired but I am still in contact with him. I work with mostly Netafim
products and all the tubing we have buried is Ram on 42" spacing. It is
buried anywhere from 30-50cm to some test stuff at 70cm. I just put a
buried system in my parent's lawn and it is working great.
I live in Central Washington where we get only 15 cm of rain a year so
irrigation is very important to us.
I monitor all the systems with radio modems and use wonderware to
interface the data and keep track of it. If anyone happened to catch
the US Farm report last week (8/9/94) they showed some of the computer
stuff I use. The individual systems are run by squareD programable
controllers.
I have started to go to notill and have alot of interest in no till and
if anyone has any mailing lists I could get on for this info please
E-Mail me with the info.
LeslieR@Hebron.connected.com

Thanks
Leslie

I currently subscribe to trickle. How can I unsubscribe, i.e. quit being a
member?

In Message Fri, 12 Aug 1994 23:02:57 -0500, MEAD2513@aol.com writes:

>For those of you that have subscribed and have not received the welcome
>information, please write to me at: MEAD2513@AOL.COM if you wish to obtain
>the welcome information and small survey.
>Thank you!
>
>Sincerely,
>
>Richard Mead - List owner
>
>p.s. If you wish to view who else is on the list, simply type:
>"rev trickle-l" (without the quotes) to the following
>address....listserv@unl.edu
>
>within minutes, a list, in chronological order of subscription placement will
>appear. At current standing, we have 89 members.

---
University of California
Riverside, CA 92521

I'D LIKE TO REVIEW THE LIST OF 89 MEMBERS AND THEIR E-MAIL ADDRESSES SO I CAN
COMMUNICATE WITH THEM.

ALSO, HOW DO I REVIEW THE BULLETIN BOARD MESSAGES WHICH HAVE BEEN PREVIOUSLY
POSTED?

I AM A NEW MEMBER OF AMERICA ON-LINE AND HAVE JUST BARELY FIGURED OUT HOW TO
USE THE E-MAIL, SO THANKS IN ADVANCE FOR YOUR PATIENCE.

Hello everyone,

I am Basant Maheshwari from the University of Western Sydney in Australia.
My areas of interest are in irrigation management, environmental hydrology
and soil conservation. My current research work relates to surface
irrigation modelling, effects of river regulation on river hydology and
soil erosion in tropics. I have a keen interest in doing research in
sub-surface drip irrigation but have not started any work yet. I have very
much enjoyed the discussion so far on this list.

Kind regards.

Basant Maheshwari

+++++++++++++++++++++++++++++++++++++
Dr. B.L. Maheshwari
School of Agriculture & Rural Development
University of Western Sydney
Richmond, NSW 2753, AUSTRALIA
Email b.maheshwari@uws.edu.au
Tel. (61+45) 701 235 or 885 652
Fax (61+45) 885 538
+++++++++++++++++++++++++++++++++++++

>ONE OF THE MOST INTERESTING, I THOUGHT, WAS THE
>USE OF DRIP IRRIGATION TECHNOLOGY IN A GREENHOUSE MOSHAV COMPLEX IN THE
GAZA
>STRIP WHICH WAS PRODUCING, PACKAGING AND EXPORTING CHERRY TOMATOES WHICH
>WERE DRIP IRRIGATED WITH SALT WATER.

>IS THIS CURRENTLY BEING DONE ANYWHERE ELSE IN THE WORLD? WHO WOULD YOU
>SUGGEST I CONTACT TO FIND OUT?

Abuot four years ago when I went to Israel for 10 days I went to kibbutz
revivim in the negev near sde boker; there, they were growing corn with
brackish (3000 ppm), hot (110 F) ground water via surface drip. At least,
that's what they told me. Also, there was a guy at the Ben Gurion Univ.
in Beersheba named Samuel Mendlinger who had bred a sweet melon, like a
canteloupe, that had high salt tolerance. Mendlinger (an American by
birth; he was from Brooklyn, I think) said he thought American farmers
missed the point when they looked at drip as a water conservation tool;
he said they should look at it as a way to increase their yields via
better control of water and nutrients. I would be interested to know
whether people on this list agree; since my drip experience is limited
to my suburban backyard, I'm not able to judge for myself.

>P.S. HOW WOULD I GO ABOUT SETTING UP A BBS FOR AGRICULTURAL WRITERS AROUND
>THE WORLD? WHO MIGHT I CONTACT ON INTERNET TO DO THIS?

Last time I checked (which was maybe two years ago) the National Association
of Agricultural Journalists (or whatever the name is) had a section in the
earth forum on America Online.

By the way ... who are you (i.e., the person who posted this query)?
There's no signature and the header is cryptic.

Russell Clemings
The Fresno Bee
1626 E St., Fresno Ca 93786
(209) 441-6371
Primary: clemings@delphi.com
Secondary: 70721.1045@compuserve.com

> missed the point when they looked at drip as a water conservation tool;
> he said they should look at it as a way to increase their yields via
> better control of water and nutrients. I would be interested to know
> whether people on this list agree; since my drip experience is limited
> to my suburban backyard, I'm not able to judge for myself.
>
Generallyy speaking there is a conservation of water when you switch to
drop especially if you are going from rill irrigation to drip. In a
buried system there is not big conservation increase. The reason is that
if you practice High Freguency Subsurface Drip HFSD you looose alot of
water through transpriration. The equation ET=water use is changed.
Evaporatin off of the surface is reduced because the drip is buried and
the use of high frequency allows the plant stomata to stay open during
the heat of the day and you loose alot water through transpiration.
There are some good articles out of Fresno by Dr Claude Phene. He did
alot of the pioneering work on this stuff.
I have a lawn under subsurface drip and it is doing welll in an arid
place where there is only 6 inches of rain and the summer temps get in
the 100's

My best to all

Leslier Roy> >

Dear Russell,
Thanks for your e-mail message. I'm just getting used to working things,
so I'm sorry if I garbled something. I hope this comes through loud and
clear.
I'll check under Envoronment on AOL to see about the ag writers network.
Thanks.
Our business in agricultural public relations and marketing services, so
I'd like to be able to tap into ag writers electronically to hire
freelancers. Also, it seems like a good way to research story ideas and
check-back with sources, which we do on all our copy.
Have you ever written an ag story in this fashion, relying primarily on
e-mail via Internet? I thought this might make an interesting story for the
newsletters from several of the organizations (American Agricultural Editors'
Association--AAEA; Agricultural Relations Council--ARC; Cooperative
Communicators' Association--CCA; National Agricultural Marketing
Association--NAMA; and for our summer intern's Agricultural Communicators of
Tomorrow--ACT) which we belong to. Also, it might make a nice article for
AgriMarketing magazine. Might we quote you in such an article?
If you are interested in freelancing from time-to-time, please send me
some of your ag/food related stories. Thanks.

Best Wishes,

Warren E. Clark
President
Clark Consulting International, Inc.
14N921 Lac Du Beatrice
West Dundee, IL 60118-3115
TEL: 800-473-7672, or 708-836-5100
FAX: 708-836-5140
AOL: AGPR
Internet: AGPR@aol.com

Richard Mead observed:
>Well once again, the mail has slowed to less than a trickle (no pun
>intended). I always feel obligated to get conversations going again.

I for one am consumed in the grape harvest ... an intense period that will
last until around the end of October. I look forward to more active
participation starting in November.

I have been asked to make a recommendation on the design parameter for a drip
system.

We have a 38 acre block with surface drip. I have suggested to our neighbor
that he go subsurface drip to reduce weed pressure and have better fertilizer
response.

The problem: We share the same well and potentially can run similtaniously
... giving great energy effeciency. The problem is that it would require
spacing his emitters 10 - 15% further to match our application rates (same
crop/variety) and maintain adequet pressure for good distribution uniformity.

The neighbor will be installing into an existing vineyard with a developed
root system.

Our drip engineer has submitted that the manufacturers are now recomending
greater emitter density. I speculate this is to facilitate maintaining
application rates while reducing surfacing. Are there other considerations?

Does anybody have some input into the importance of emitter density in
perenniel crops?

How does effective wetted volume of subsurface compare to surface drip given
same water applied per emitter?

Given the potential for cutting energy cost significantly by stretching out
the spacing a little, are there some major problems to be expected?

I am looking forward to your collective wisdom.
Craig

Once again I feel obligated to get conversations stimulated for
our trickle-l group. This week I thought the topic of fertigation (injecting
fertilzer into the irrigation water) would be an interesting one. Those of us
in the northern hemisphere are probably finishing fertigation as the season
tapers, while those in the southern hemisphere are just now starting to at
least plan for fertigation. So now would be an ideal time to discuss what has
worked and what some are planning to use.
The following are advantages of fertigation which are not necessarily in
order.
Please add to this list if I've left anything out.

1) Less equipment required to apply the fertilzer.
2) Less energy is used to apply fertilizer.
3) Usually less labor is needed to supervise the fertilize injection.
4) The nutrients are regulated and monitored more carefully.
5) The nutrients are distributed more evenly throughout the entire root zone
(what I called "spoon fed" to the roots)
6) The fertilzer can be applied to the profile any time.
7) Soil compaction is avoided due to the fact that equipment never enters the
field.
8) The crop is not damaged as with conventional tractor fertilizer placement.
9) Nutrients can be supplied to meet the exact need of the crop.

Most individuals who use subsurface drip, have stated that they obtain at
least a 50% reduction in fertilizer use. Has anyone experienced more or less
fertilizer efficiency?

Most talk about fertigation concerns nitrogen fertilizer. The following are
Nitrogen fertilizers used in fertigation practices. Please add to the list if
I'm missing any anything. I would appreciate what the pros and cons are on
these various compounds.

Nitrogen Fertilzers Grade

Ammonium Nitrate 34-0-0
Ammonium Polysulfide 20-0-0
Ammonium Sulfate 21-0-0
Ammonium Thiosulfate 12-0-0
Anhydrous Ammonia 82-0-0
Calcium Nitrate 16-0-0
Urea 46-0-0
Urea Sulfuric 28-0-0
Urea Ammonium Nitrate 32-0-0
Calcium Ammonium Nitrate 17-0-0

Do you acidify your water with some of these fertilzers to eliminate any
ammonia volatilization?
How do you inject the fertilzer? a) Venturi principle (b) Injection pump (c)
Proportioning pump (d) other

I hope this is enough to get discussions going again. Thanks for your
participation!!

Richard M. Mead
List owner

(some information on this note was supplied by Dr. Tom Ruehr at Cal Poly San
Luis Obispo, Ca)

Intro to the 90 subscribers as of 8/21/94
My name is Phil Soderman and have a wholesale container nursery in So
California. Trickle Irrigation is a little different in container plants,
pot sizes are 6" or 1 gal. 2 gal and 10" baskets. The soil we use is not
really soil but a mixture of sand and a wood residual (sawdust or bark)
or in some of our greenhouse grown containers is a mixture of Peatmoss
and Pearlite. Weight is a problem so real soil is not normally used.
For 2 1/2 acres of production I use Chapin watering tubes (1 per
pot 72,000 tubes) with a lead weight on the end. The inside diameter is .060 in. so the flow rate is
slow in the area of 1 gph. The systems are set in blocks with solenoids
controlled electronically. I have a 2" Smith Measuremix 1:200
proportioner. I supply my plants with a complete fertilizer
N,P,K,Ca,Fe,Zn,Mn,Mo. All added as simples to the stock tanks. P is
applied as Phosphoric Acid both for P2O5 and pH control, water starts 7.5+.
We use a "Pulse Irrigation Technique" to maximize wetting of the soil and
nutrient uptake. Cycles run 2 min. and come on again 2 hours later and
again if necessary. Control is strictly time based no tensiometers or
gypsum blocks.
We find on our ornamentals that Nitrate promotes hard growth of both stems
and leaves. Urea based nitrogen promotes both leaf expansion and lateral
branching. So we try to balance the Nitrogen from 3 sources(NO3,NH4,Urea)
for balanced growth and REACTION pH.
Reaction pH, Container soils usually have little or no pH buffering
capacity and during crop cycles pH shifts can occur. With our pH 7.5+
water the trend is usually higher. Selecting a fertilizer formula
calculated to balance the + and - pH shifts of the reaction of the
simples mimimizes the shift. If anyone is interested in details I will
provide more info. Phil Soderman sgrower1@rain.org

I also produce 4" potted crops using a Dutch rolling tray EBB and Flow
irrigation system and produce other containers under sprinklers.

Survey Response Add to your list:
UN32 delivered as Liquid

Potassium Nitrate 14-0-44
KNO3 is a good dual nutrient source where Both N & K are needed and
sailinity as well as CL is a problem. It is slower to dissolve than KCL.

Not Commonly used but available
Diammonium Phosphate 21-53-0 DON'T EVER MIX DAP and CaNO3 It precipitates
in the stock tank and in the DRIP TUBES or Chapin Tape. EVEN IF
YOU USE A DOUBLE HEADED INJECTOR SYSTEM.

Monoammonium Phosphate 14?-44?-0

>
> Do you acidify your water with some of these fertilzers to eliminate any
> ammonia volatilization?
I use Phos Acid to control pH (target pH 6.5) of Irrigation water.

> How do you inject the fertilzer? a) Venturi principle (b) Injection pump (c)
> Proportioning pump (d) other
I use a Smith Injection Pump.

> I hope this is enough to get discussions going again. Thanks for your
> participation!!
>
>
> Richard M. Mead
> List owner
>
> (some information on this note was supplied by Dr. Tom Ruehr at Cal Poly San
> Luis Obispo, Ca)
>
>
>

Craig,
Your questions are pertinent to anyone thinking of subsurface drip
installations.
For your question regarding emitter density, I would submit without knowing
the depth of placement and type of soil, that one needs to implement high
frequency irrigations and install emitters with higher output per emitter(to
a certain point). We have a project on alfalfa grown in a clay soil where the
emitters are spaced 40 inches apart, buried 27 inches deep and lateral
spacing of 80 inches. The alfalfa is doing fine. The emitter output is 2
Lhr-1. Everytime the crop looses 0.04 inches of known "ET", we apply 0.04
inches of water. We consider this to be high frequency, especially on 0.5
inch ET days.
Regarding >How does effective wetted volume of subsurface compare to surface
drip given same water applied per emiter?<...well according to Ben-Asher in
CIT publication No. 92-1001, "the disadvantage of SDI results from its small
radius of wetted front which may require additional emitters per unit area"
(compared to DI or surface drip irrigation).
He also noted three observations in a clay loam soil:
1) Under DI, a given water volume is stored ina soil which is about half the
storing volume of SDI.
2) SDI wetting fron is roughly 80% of DI soucrce
3) SDI at limited depths (6 inches) has a large water absorption volume when
infiltration starts. As time proceeds, the wetting fron is reached and
intercepted by the soil surface. Without space for outware flow, soil volume
availale for storing water becomes smaller than that of deeper emitters.
Thus, SDI absorbs mroe soil infiltrating area than DI, requiring closer
spacing of emitters.
I grabed 4 points on a graph to illustrate the above mentioned factors.
SDI DI
Spacing (2 Lhr-1) 0.45m 0.55m spacing
Spacing (4 LHr-1) 0.55m 0.68m spacing

Also, this chart:
Surface
Subsurface
Wetted Soil volume small Large
Change in volumetric content Large Small
Surface Evap Large
negligible
Total transpiration Small Large
Irrigation efficiency Small Large

Major problems of expanding emitter spacing would be obvious dry spots and
potential surfacing if one is not careful with over irrigation.
Unfortunately, there are few models to simulate three dimensional flow in
various soils to predict the exact spacing of emitters and laterals.....but
the industry is young!!
Hope this helps you Craig.

Richard Mead

>Richard Mead
>List owner
>

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rmail witch!unl.edu!trickle-l Multiple recipients of list <trickle-l@unl.edu>
exited with status 2

===== stderr was =====
sh: syntax error at line 1: `end of file' unexpected
>

What am I doing wrong? Whenever I enter a message I get this
result.

Re: Drip Emitter spacing

To All,

Richard Mead had a very interesting discussion on subsurface drip vs
above
ground drip. I would agree with all his statements concerning the
wetting
areas of SDI vs DI. The one statement that I think needs alot more
discussion
is the fact that maybe more emitters will be needed along a given tube to
make
up the difference of the reduced wetting volume.
We have been raising hops on SDI andDI for over 8 years. We have depths
of 35
cm to 65 cm for the buried tubes. We have kind've settled on 35 cm
because it
gets away from some of the problems of soil variablity. We live in
Central
Washington and our soils are very variable within a field. Anyway our
plants
are on 130 cm spacing and our drip emitters are at 130 cm with 1 l/hr
emitters.
We use Netafim Ram and have had very good luck with them given some of
our
uneven topography. For the record we use all Israel made equip.
My cousin is using SDI and he has his emitters on 60 cm spacing with 1
l/hr
emitters. His are buried at 45 cm and he has alot of problem with
surfacing.
He has 600' runs and he has to run his sets very long because of the
amount of
time it takes to fill the lines.
We have done some digging around our emitters and with our spacing we
end up
with a sphere of moisture around each emitter. My cousin's wetting
front is
continious. It is hard to say which is better though as far as yields
go. The
one thing that is for sure is that we are able to run at a higher
frequency
than my cousing because of runs having less emitters and the fill time is
fast
thus we do not end up with uneven applications.
I can't address all the issues Mr Mead brought up but one that got me
was
that, I think he said that SDI has a lower transpiration rate than above
ground. I was always told that SDI with high frequency would keep the
plant
transpiring during hot weather because the Stomata would be kept open
and the
moisture would just pour out through the open.
If my note here seems to ramble on a bit . excuss me because we are in
the
middle of hop harvest(24 hrs a day for a month) and my brain is a bit fried.

Leslie

Dear Steve Jordon,
I have no idea what is going on. I'll ask the Internet gods and see what is
up. Seems like you're doing everything right to me.
Hang in there.

Richard Mead

If I stated that SDI has lower transpiration rates, I am in error and stand
corrected(SDI should have higher rates of transpiration due to water being
available to the plant on a more regular basis). Maybe my brain was fried
also. SORRY!
I'll have to proof read my stuff next time.

Richard Mead

Dear new subscriber,
Thank you for joining TRICKLE-L email. The following is a welcome statement I
made about a month ago when this thing got going. Since then, we have had
discussions on Chlorine injections, fertigation, surface vs subsurface
irrigations etc. Please feel free to pop in questions relating to anything
about drip irrigation (surface or subsurface).
To see who else is listed, post the following statement to LISTSERV@UNL.EDU

REV TRICKLE-L

This should show in order or subscription who is on the list, just in case
you are interested.
Again ,welcome.......

WELCOME ALL MEMBERS!!
After only a few days of beginning this email list, we have an international
assortment of individuals all interested in trickle irrigation. To introduce
myself, I am a soil scientist working at the Water Management Research
Laboratory associated with the Agricultural Research Service of the U.S.D.A
in Fresno, California. For those not familiar to Fresno, it is in the middle
of California, the heart of the San Joaquin valley, where irrigated
agriculture is the dominate industry. For the past 16 years, our lab has done
research on various aspects of irrigation and drainage, yet the main emphasis
in the last 10 years has been on subsurface drip irrigation (sometime this is
known as SDI or SSDI or SSD). You pick which one you like.... it does'nt
matter to us. But, when one is talking about drip or trickle irrigation,
let's emphasize either surface or subsurface drip irrigation. Assuming the
popularity of subsurface drip irrigation, the majority of conversation on
this email list will be subsurface irrigation. However, it is not limited to
subsurface drip irrigation alone.
To get things started, I thought that it would be appropriate to initiate a
couple of general questions
for people to respond to: (It is not necessary to answer all questions).

1) Briefly, what is your affiliation with trickle irrigation?
2) What crops or plants do you use drip irrigation on?
3) If using subsurface drip irrigation, what is the average depth of
placement of the drip line? Believe me, this is one of the biggest questions
for the industry, and there is debate among experts as to how deep one should
go. Three dimensional models are in their infancy. There is alot of work to
be done on this aspect.
4) What problems have you encountered with subsurface drip?
5) Fertigation is a real advantage of drip irrigation. What form of N, P and
K have you been trying and to what success?
6) Have you experienced a reduction in fertilizer and water use?
7) Do you have water quality problems? If so, how do you tackle the
situation?
8) How frequent do you irrigate? Many times a day or just one long session
per day or several days?
9) Do you have rodent damage? If so, how do you tackle the problem?
10) Are you pleased with the uniformity of your system or systems? Were they
designed correctly?
The above questions should be enough to get things going. I realize we have
alot of researchers online and these questions might seem elementary, yet we
all could be approaching problems from different angles. Also, as
researchers, we could benefit any farmer that could be taping into this
information system. Thus, they might be asking us some interesting questions
that we never thought of. So, once again, welcome and let the games begin!
Sincerely,
Richard M. Mead
Soil Scientist
USDA-ARS-WMRL

Hi, my name is Gordon Couger I am a software specialist for the
Biosystems and Ag Engineering department at Oklahoma State
University in Stillwater, OK. I am currently working with capacitive
soil moisture meter. So far the results have been promising. We have
two prototypes running. As it looks right now the cost of building
one is about $80.

I also am interested in drip to utilize low volumes of poor quality water.

I do embedded systems programming on 68HC11, MSDOS and PIC
computers. I am involved in CAN computer networks on farm
machinery. Some of my work involves computer models of erosion and
water flow from 1 cm to 1 mile data points.

So far the list has been interesting.
Gordon

Gordon Couger
Biosystems & Agricultural Engineering
Oklahoma State Universtiy Stillwater OK

Hi, my name is Ed Martin and I'm the Extension Irrigation Specialist for
the University of Arizona. I've been here for only two years and I'm
just getting started in SSD.

We used SSD mostly for vegetable production, though some people use it
for row crops, but that is very rare. We grow a variety of crops during
the winter months including cauliflower, carrots, onions, tomatoes,
peppers, etc.

The average depth of our tape is about 6-8 inches. We have fairly
clayey soils with good water movement both vertically and horizontally.

One problem we do have is with good uniformity, due mainly to large soil
clods. It is difficult to get the seed bed prepared properly and quite
often I have found that large soil clods have constricted flow and cause
poor uniformity.

We use surface water and although we have some problems with algae and
bacteria, we don't keep the tubing in all year and we re-injected our
tubing at the beginning of each winter. This is done mainly because we
don't have the proper implements that will allow us to do proper tillage
without ruining the drip lines. I know the implements exist, I just
need to find some funds.

So, I am interested in using these systems to help me determine crop
water use curves that can be used to develop Kc data? Any suggestions?

If anyone has some sage advice for a rookie, my E-mail ears are wide
open! Thanks.

On your tillage problem , you might contact Stewart Frankee at Medina at
210-426-3011. He has a soil activator that has done wonders on hardpan soils
, it may help.

Greetings all:

As you will soon read, I'm at the amateur end of the spectrum.

I have a few acres at 2400 feet in the foothills of California's Sierra Nevada
mountains, about 150 miles north of Yosemite National Park. The soil has
very little organic matter, but I have a plan for that. What water we have
comes from a spring, so conservation is very much on my mind. (We asked the
federal government for an aquaduct, but they were busy elsewhere :-))

We will be using drip irrigation for a range of vegetable, all planted in
raised beds, and a small orchard. A vineyard will be established later, if
all goes well.

My experience with drip irrigation is limited to a previous garden. That
experience (the drips were all on the surface) showed me that getting
uniform coverage is a problem. As I had a (very) small plot, I attempted
to place the drips individually. That was a mistake, I believe. This time
I will go for uniform placement based on soil evaluation.

I've never seen anything on subsurface drips. Anyone care to post a brief
introduction?

We are planning to use organic fertilization exclusively, with emphasis on
locally-produced compost. I would imagine that that would make sufsurface
drips a bad idea.

Regards,

Geoffrey Leach

For those who have just subscribed or those who love reruns,
we now have a way to access discussions which occured in July. Let's hope it
works.
Simply send to the Listserv@unl.edu the command

GET TRICKLE-L LOG9407

This should bring up all postings for the 7th month of '94.
Along with those postings will be discussions on fertigation, chlorination,
theories of subsurface drip depth of placement,and several welcome messages
for rookies. In the future, as our subscriber list grows and more discussions
occur, one can access any month since the inception of this list.
Soon, I plan to post several informative, yet general discussions concerning
the following topics:
- Reduce nitrate contamination due to subsurface drip irrigation
-Irrigation scheduling sensor technology
-Research on drip irrigated cotton
-Recycled water

I would like responses from everyone if they find these topics of interest.
Also, if anyone out there could reflect their experience on the following
topics:
-What crop CAN'T be grown with subsurface drip?.. (celery for one)
-How does one maintain annual row crop bed shape
(w/ or without Sundance bed shaping equipment)?
-Problems or successes with drip tape/tube installation
-How do you save costs???
-Is root intrusion that big of a problem?? If so, how do you overcome it?
-Rodent damage? Any solutions...?

Again, I just thought I would inform and stimulate interest out there in
irrigation cyberspace. Thanks for subscribing!!!!!

Richard Mead
List owner

Dear Geoffrey Leach,
I saw your note on Trickle-L, and would like to send you an issue of our
publication on sustainable agriculture called *Farmer to Farmer.* We
don't yet do much on irrigation, but there is much on organic amendments
and other interesting topics. So if you're interested, please give me a
mailing address. Also, you'll undoubtedly get more detailed info on
subsurface drip, but basically, it's a highly conserving type of system
that is basically tubing with built-in emitters that drip water just
below the surface. Both Toro and Geoflow make the product (Toro's is
called Netafim). When I was a landscape architect, we used it and had
good luck with it; it has even been used on lawns.
Good luck!
_lori Pottinger, assistant editor
e-mail: f2f@igc.apc.org

Warwick Rowell

Vocation: All aspects of land care in the SW corner of Western Australia.

Current projects:

Developing villages as a part of rural communities.

Running self-directed learning programs for land managers

EEPO: Everybody's Electronic Post office- batch email for country people.

Managing Director - Rowell Consulting Services Pty Ltd:
Since 1971, management consulting, from multinationals to green one-person
businesses..

Managing Director - Intone Pty Ltd:
Small ethical investment company. Revolving Funds for small businesses.
Broker for people wanting ethical funds for projects which will earn money.

Senior Partner, Permaculture Applications, Consultancy & Education:
A loose consortium of Permaculture Certificate holders:

Applications: Several businesses, using Permaculture ethics and
principles, which share resources & expertise.

Consultancy: "We can help you apply permaculture design principles
to your life, your business, or your property."

Education: "Action Learning workshops, Introduction & Permaculture
Design Certificate Courses, so you can do design work yourself.

On the Executive of Permaculture Association and the Permaculture Institute
and Land Management Society in WA. Previously President of Subiaco Ratepayers Association, SAVE African
Endangered Wildlife Foundation, Subiaco Business Association, Editor for
Land Management Society, and active in Men of The Trees.

Other Interests:
radical/regional economics, writing, public speaking, raising kids.
Started playing with computers in 1970 - theyre an addiction..

Qualifications:
M.Sc, B.Comm (Hons), Dip. Perm. Des.
_____________________________________________________________
| warwick.rowell@eepo.dialix.oz.au |
| |
| Management Consultant Permaculture Designer |
|__"Helping Managers Learn"____"Helping Land Managers Learn"__|
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