Archive TRICKLE-L: file log9507, part 1/1, size 42745 bytes:

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> My question to the members of the list: are
>there any examples of unlimited agricultural irrigation with municipal
>wastewater effluent which has been treated but not recharged into the
>groundwater? I am particularly interested in examples from the state of
>California due to the similar climatic conditions and its reputation for
>being particularly strict concerning safety regulations. thank you.

Today's regulatory climate: It is regulated on a case by case basis.
Reclaimed water may be okay on pasture for non milk cows, trees if the fruit
or nut does not come in contact with ground or water.

They are very jealous about using reclaimed water on vegetables which are
eaten raw. In Monterey County, they did a long term study (you heard about
it?) with surface water - no treament, partial treament, full treatment,
"fresh" water. Conclusion: no difference for health. Action: they could
grow crops IF the crops were labeled in the store that they were grown with
reclaimed water.

Effluent through drip might work on "aerial" vegetables: brocoli,
cauliflower, artichokes, peppers but not through ground veggies: lettuce,
celery. ?? tomatoes?
Steve Jordan @ Second Foundation

The following comments and questions pertain to current California law, yet
other states and/or countries might be experiencing similar situations.

Back in 1989, California passed the "California Integrated Waste Management
Act" or CIWMA. This law enforces a 50% reduction in materials going into the
state's landfills by the year 2000.

Some California farmers have implemented municipal organic materials
(separated tree and lawn clippings, food processing waste and other sources
of organic matter) into their cultural practices via on farm composting. Many
of these farmers use drip irrigation technology. Farmers are reporting fewer
weeds, and less soil born diseases.

My questions to those who are familiar with the CIWMA law and subsequent
cultural practices are:

1) What are the positive and negative aspect of using municipal green waste
(composted) when using drip applications? Specifically, how much do you apply
(tons/land area) and how do you apply it......Sundance system, other
implements??

2) With this relatively new landfill law and the advent of more and more drip
irrigation systems, where do the old drip tape or hose systems go? Are there
recycling programs within the drip industry to re-make drip systems? Is the
drip tape "waste" even allowed in a landfill in California (or else where)?

For those of you outside California, please let us know if you are
experiencing similar laws or cultural practices.

Richard Mead
Trickle-L owner/manager

>2) With this relatively new landfill law and the advent of more and more drip
>irrigation systems, where do the old drip tape or hose systems go? Are there
>recycling programs within the drip industry to re-make drip systems? Is the
>drip tape "waste" even allowed in a landfill in California (or else where)?
>

One manufacturer (Roberts, I believe) claims or guarantees recyclability.
There are hitches in the process (I think). I have some Roberts, but havent
had to pull it yet. One big problem with recycling is the cleanliness.
Scale, roots, and _dirt_ cause problems.
Steve Jordan @ Second Foundation

The Irrigation Training and Research Center (ITRC) at Cal Poly has just
published its book on "FERTIGATION". This new 293 page book is
state-of-the-art, and answers questions regarding fertilizer types and
selection, maintenance of drip systems with chemicals, nutrient monitoring,
safety, hardware, injection equipment, etc.

The other state-of-the-art book we recently published is "Drip and
Microirrigation for Trees, Vines, and Row Crops (with special sections on
buried drip)".

If you are interested in these books, let me (Charles Burt)know bye-mail,
or FAX a request to:
Irrigation Training and Research Center
Cal Poly
San Luis Obispo, CA 93407

phone: 805-756-2434
FAX: 805-756-2433

A lot of the questions which have been asked over this network have been
answered in these 2 books.

The following is a response from Dr. Gary Clark concerning municipal waste in
agricultural production.

I was involved in a large statewide project in Florida that involved
using MSWC in irrigated and non-irr. agriculture, vegetables,
ornamentals, trees, ... The data is all in report form and in
various stages of publishing (mine will be prepared later this year).
The project ran for two years (1992-1994) and was coordinated by Dr.
Wayne Smith (address below)*. Wayne has all of the reports in compiled
and spiral bound format.

My study looked at drip irrigated veg. prod. (staked tomatos, bell
peppers) with 0, 30, and 60 ton/ac of MSWC as a one time
incorporation. Initially MSWC was not fully composted upon delivery
(still "green") and had too much foreign material (glass, plastic...)
in it. In general, MSWC was beneficial and resulted in yield
increases after it had "field matured". The first season had yield
decreases from MSWC due probably to N rob. However, after the first
season and field maturing, the benefits opened my skeptical eyes. I
was really impressed. I could elaborate, but need to move on.

Gary A. Clark
Associate Professor
Biological and Agricultural Engineering
147 Seaton Hall
Kansas State University
Manhattan, KS 66502
913.532.5580 (Tel)
913.532.5825 (FAX)
gclark@falcon.age.ksu.edu

*
Dr. Wayne Smith
University of Florida
Center for Biomass Programs-IFAS
P.O. Box 110940
Gainesville, FL 32611-0940
Tel. 904-392-1511
Fax. 904-392-9033

Prof. Burt :

Please inform how the books mentioned can be ordered (and their cost).

Thank you,

Sergio Goldemberg (GlynMiami@aol.com)

On Mon, 3 Jul 1995, Charles M. Burt wrote:
> If you are interested in these books, let me (Charles Burt)know bye-mail,
> or FAX a request to:
> Irrigation Training and Research Center
> Cal Poly
> San Luis Obispo, CA 93407
>
> phone: 805-756-2434
> FAX: 805-756-2433
>

Awww c'mon, you're not gonna subject us to *snail-mail* now are you?

How about details on-line (aka *here*), pretty please?

Dear Sirs:
I will be delighted to have a copy of your new books.
Thank you in advance
Sincerely
Gideon Oron
Ben-Gurion University
The Institute for Desert Research
Kiryat Sde-Boker
Israel 84990
Fax: 972-7-557-042

On Mon, 3 Jul 1995, Charles M. Burt wrote:

> The Irrigation Training and Research Center (ITRC) at Cal Poly has just
> published its book on "FERTIGATION". This new 293 page book is
> state-of-the-art, and answers questions regarding fertilizer types and
> selection, maintenance of drip systems with chemicals, nutrient monitoring,
> safety, hardware, injection equipment, etc.
>
> The other state-of-the-art book we recently published is "Drip and
> Microirrigation for Trees, Vines, and Row Crops (with special sections on
> buried drip)".
>
> If you are interested in these books, let me (Charles Burt)know bye-mail,
> or FAX a request to:
> Irrigation Training and Research Center
> Cal Poly
> San Luis Obispo, CA 93407
>
> phone: 805-756-2434
> FAX: 805-756-2433
>
> A lot of the questions which have been asked over this network have been
> answered in these 2 books.
>
>

The following questions I have received from two different "outside" sources
for me to post on Trickle-L. Please respond if you have any answers for
these two individuals. You may post to me personally or to the group as a
whole.
****************************************************************
I received a recent query from an industrialist in Egypt who wishes to start
up a plastics company with the intent of manufacturing irrigation components
in general, and for trickle and spray applications in particular.
If you know of any US companies which may be interested in collaborating with
me on this front in either setting up a joint venture or providing the
technical know how for the said Egyptian project, please kindly provide the
relevant information for me to follow up on it.
Please note that I will be travelling to Egypt in 3 weeks time and would
therefore appreciate any preliminary information in this regards.

Best regards,
Dr. Hani Badawi
President - Hanimex
6024 Cricket Drive,
Lakelan, FL 33813

********************************************
"Does anyone know of any quantitave data available on relationships
between suspended sediments in agricultural water and wear on irrigation
system components (pumps, sprinkler nozzles, fan jets, etc.) and costs
therefrom? Data that is site-specific is acceptable for my purpose.

J. Finley
JFinley607@aol.com

I am working with the Center for Irrigation Technology (CIT) on a project
to evaluate a product that prevents mineral plugging in drip emitters. We
have come up with the following idea for a protocol:

1. Produce a solution of saturated gypsum in a mixing tank.
2. Filter the solution.
3. Run the saturated solution through a bank of drip emitters for 12 hours.
4. Let the emitters set for 12 hours.
5. Repeat this cycle until the control solution emitters plug.

The constraints are as follows:
1. It needs to be relatively quick. (not more than 3 weeks.)
2. It needs to be fairly simple. We will be using a large volume of
solution that won't be recycled, so creating the solution will be an issue.

I would appreciate feedback. (Especially any references)

Denis Bacon
CSU Fresno
School of Agricultural Sciences and Technology
Fresno, Ca 93740-0079

Denis:
There is a fairly complex relationship between carbonate precipitate and
carbonate in solution. It has been a while since I dealt with it but if
you want a precipitate to form, as I think you do I think it would be worth
looking into. Injecting co2 might help. Again the reaction is faily complex
and it is an equlibrium reaction.

Bob Edling- LSU

Plugging? simulation-try diammonium phosphate and calcium nitrate=ca
ammonium phosphate
usually fairly good at plugging an dissolvable using a phos acid solution.
>Contents:
>drip plugging simulation (denis_bacon@csufresno.edu (Denis Bacon))
>
>----------------------------------------------------------------------
>
>Date: Tue, 11 Jul 95 08:32:46 PDT
>From: denis_bacon@csufresno.edu (Denis Bacon)
>Subject: drip plugging simulation
>
>I am working with the Center for Irrigation Technology (CIT) on a project
>to evaluate a product that prevents mineral plugging in drip emitters. We
>have come up with the following idea for a protocol:
>
>1. Produce a solution of saturated gypsum in a mixing tank.
>2. Filter the solution.
>3. Run the saturated solution through a bank of drip emitters for 12 hours.
>4. Let the emitters set for 12 hours.
>5. Repeat this cycle until the control solution emitters plug.
>
>The constraints are as follows:
>1. It needs to be relatively quick. (not more than 3 weeks.)
>2. It needs to be fairly simple. We will be using a large volume of
>solution that won't be recycled, so creating the solution will be an issue.
>
>
>
>I would appreciate feedback. (Especially any references)
>
>
>
>Denis Bacon
>CSU Fresno
>School of Agricultural Sciences and Technology
>Fresno, Ca 93740-0079
>
>
>
>
>------------------------------
>End of Digest
>************************
>
>
Phil Soderman sgrower1@rain.org
Carpinteria, California USA
ZONE 10

I have been following the discussion by Denis Bacon on trying to plug
emitters by using gypsum in solution.
I have been injecting a gypsum solution into our drip system to help in
flushing of salts and also for better water infiltration.
Now if injecting gypsum will plug the emitters over time I need to readjust
my thinking here. I understood that this fine grade gypsum in solution
would not plug my emitters
Any comments would be appreciated

On Thu, 13 Jul 1995, Roy Leslie wrote:

> I have been following the discussion by Denis Bacon on trying to plug
> emitters by using gypsum in solution.
> I have been injecting a gypsum solution into our drip system to help in
> flushing of salts and also for better water infiltration.
> Now if injecting gypsum will plug the emitters over time I need to readjust
> my thinking here. I understood that this fine grade gypsum in solution
> would not plug my emitters
> Any comments would be appreciated
>
I guess that the possibilities of having gypsum plug the emitters (i.e.
precipitating) depend on its concentration, the composition of the water,
its properties and the environmental conditions. There is a program
called MINTEQA2 developed by EPA that calculates the speciation in a
given water under specified environmental conditions. That might give an
approximation about what could happen. I don't think that a conclusive
answer can be given but that the response will depend on the prevailing
circumstances.
Armando Tasistro (Mexico)

I would like to have these books. Please send them to
The SE Center @ Ocean Arks
ATT: J.M Keane
PO Box 4245
Chatt Tn.
37405

Some irrigation researchers are starting to use new devices to monitor soil
moisture. In the not to distant past, the neutron probe, tensiometers,
various forms of gypsum blocks and good old hand soil sampling were THE way
to monitor what goes on in the soil under a given irrigation treatment. We at
the Water Management Research Lab have been working with capacitance probes
for the last couple of years.

Without going into too much detail on how they work (contact me personally if
you want details), capacitance probes use high frequency radio waves to
detect moisture levels in the soil. The probes are safe, accurate and easy
to use. These probes can be installed permanently in the soil or used as a
portable device. After installing these probes in several subsurface drip
irrigated fields, and monitoring every hour, 24 hours a day, we have begun to
notice interesting patterns of water use and moisture distribution patterns.
The main pattern I have observed the most is one that I "think" displays the
difference in how the subsurface drip systems were installed.

Basically, the shanked-in drip systems show "spikes" in soil moisture with
each irrigation. This can readily be seen when using high frequency
irrigation (e.g. four irrigations per day will display four distinct spikes
in water content, albeit minor inflections.....something like a saw tooth).
However, the subsurface drip systems which were installed using the trenching
method display very smooth patterns of soil moisture with little or no
detected "spikes" in soil moisture patterns. This makes me wonder about
potential uniformity differences between the two installation methods. I have
my own theories about the reasons for the differences, but I would like to
hear from others for their view.

Eventually, we will put graphs displaying the above phenomena on our WWW
homepage. I'll let everyone know when it is available for viewing.

Richard Mead
Soil Scientist
Trickle-L manager/owner

This week marks the one year anniversary of Trickle-L. Our discussion list
has grown to almost 300 subscribers. The topics discussed over the last year
have been interesting and diverse.
I would like to take this opportunity to thank the University of Nebraska at
Lincoln for their assistance in help setting up the file server for Trickle-L
and all the Trickle-L participants for faithfully hanging in there to either
contribute or just observing from the sidelines. If anyone would like to view
a brief history of Trickle-L and see what countries are represented, please
refer to our home page on the WEB, specifically the URL :
http://asset.arsusda.gov/anniv.html

If anyone has not received my personal welcome message with survey questions,
please let me know. Also, if you would like to recommend a topic for
discussion, drop me a line. You can get in touch with me at either:

mead2513@aol.com or
rmead@asrr.arsusda.gov

Richard Mead
Soil Scientist
Trickle-L manager/owner

Richard,

Interesting observation regarding spikes with shanked-in SDI vs.
no spikes with trenched-in SDI. I would not be surprised if the micro-
(mini?) scale uniformity was affected by instalation method. Of course
you'd have to be looking at the same soil type.

-Ken Shackel

If I understand the differences in your shanking vs trenching
terminology well enough, I would guess the trench would be wider than
than the shank and more granular initially. This should buffer soil
water redistributions to a greater extent than the shank which
probably has differential fracturing of the soil. The shank might
have areas of fast water redistibution where the shank has "sliced"
thru and buffered soil water redistribution in "well fractured"
areas, and possibly preferential flow in cavities left by the
shanking operation. This is a possible explanation for what you are
seeing.

I have joked that in some soils if you trench, you can backfill
without the waterline in place and still get fair water distribution
for a significant period of time.

As to the importance of uniformity difference, that's a good
question. It once again points out that uniformity in SDI
**eventually** must address more than irrigation hardware. As Ken
Shackel pointed out, soils are an issue. Also the lateral extent of
the rootzone.

Is it fair to say trenching would be considerbly more expensive than
shanking in your situation? The other question would be "Is there an
economic significance to the differences in soil water
redistributions?".

Nevertheless, very interesting observations. Forge on, Richard.

Freddie Lamm
*

-------------------------------------------------------------------
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. ------

>Eventually, we will put graphs displaying the above phenomena on our WWW
>homepage. I'll let everyone know when it is available for viewing.

The page with this article and 1 graph (so far) can be found under:

http://asset.arsusda.gov/WMRL.html

Under the heading "TRICKLE-L" is an option to view the graph.

The graph can also be downloaded using anonymous ftp:

ftp to
asrr.arsusda.gov

login as
anonymous

change directory to
/pub/asrr/

filename is
wetlys.gif

==========================================================================
Richard Soppe subscribe to
Water Management Research lab TRICKLE-L@UNL.EDU
ARS/USDA or visit
2021 S. Peach Ave http://asset.arsusda.gov/WMRL.html
Fresno CA 93727-5951 for the latest in drip irrigation
phone: (209)453-3119
fax: (209)453-3122
==========================================================================

I believe I am going to get an Net address and drop this service as all I am
really using AOL for is a access to the Web and it is not cost effective!!!!

Regarding F. Lamm's comment >Is it fair to say trenching would be considerbly
more expensive than shanking in your situation?<

Yes, I am positive that trenching would be more expensive! The only reason
we have trenched SDI installations is from the original installation of the
first SDI experimental plots of our lab (West Side Field Station, Five
Points,California) which were installed more than 10 years ago. That was the
only method known at the time, plus it is a small plot (relatively speaking).
In another trenched SDI installation (more recent) we hand trenched an SDI
system inside our new lysimeters in Parlier. Similar smooth moisture patterns
exist there also. I am not recommending trenching, although some landscaping
with SDI and turf are done this way.

Also regarding >The other question would be "Is there an economic
significance to the differences in soil water redistributions?".<

I really don't know if there would be any economic differences between the
two, but I tend to think it would be neglegible if any. As you say, they are
interesting observations.

Thanks for all the comments Trickle-L gang!!

Richard Mead
Trickle-L manager/owner

HAPPY 1 YEAR ANNIVERSARY, TRICKLE-L!

I want to thank Mead for maintaining and keeping this list active. Thanks
also to all those who have been instrumental in its establishment. Lastly,
I just want to wish all the list members a HAPPY ANNIVERSARY.

Regards, Give.

HAPPY ANNIVERSARY

Tatku, ja ci wierze - juz wystarczy. Roboty ciagle mam za duzo ale jakos
sobie radze. 12-go jade na dwa dni do San Antonio (Texas) - tam jest podobno
bardzo ladnie. Lece na wyklady. Caluje. Dorota.

A few weeks ago there was a message about books. I would like a copy of
these also.

Sure Shot Irrigation
18666 Redmond Way # H-2058
Redmond, WA. 98052
Attn: Carl Taylor

Thank You Very Much.

whaaaaaaaat?

Richard Soppe (our WWW homepage architect and co-creator of Trickle-L)
and I have chosen some abstracts from the April '95 Microirrigation Congress
to present to Trickle-L subscribers for discussion. In future weeks, we will
post one abstract per week along with several questions, definitions or
comments related to the particular abstract. I hope this stimulates more
discussion. If anyone wants a particular "drip" related abstract presented,
please send it to me via email.

The following is an abstract related to an analysis of soil moisture sensor
placement. It is rather heavy in terminology. Not all the abstracts Mr. Soppe
and I have chosen are this complex. We'll try to present a wide range of drip
topics with various levels of nomenclature.
******************************************************************************
***************
Soil Water Sensor Placement and Interpretation for Drip Irrigation
Management in Heterogeneous Soils

Dani Or
Utah State University
Logan, Utah

Many drip irrigation management schemes rely on frequent monitoring of soil
water content and matric potential using various sensors (e.g.,
tensiometers, gypsum blocks, or time domain relectometry probes). The
information is used either for scheduling irrigation, or for adjusting
schedules based on evapotranspiration measurements. Most soils exhibit
spatial variations in their hydraulic properties, which in turn, induce
spatial variations in wetting patterns about the drippers. These variations
present a problem for sensor placement relative to the dripper, and
complicate interpretation of soil water information. The objective of this
study was to quantify effects of mild spatial variation in soil hydraulic
properties on the mean and variance of soil water content and matric
potential distribution about point sources and the consequences on soil
water sensor placement and interpretation.

The stochastic* approach considers the soil properties as random space
functions. A first-order small-perturbation** expansion was applied to
analytical solutions of stead state flow from point sources. The stochastic
analysis presented here is limited to conditions of mild variations in
soil hydraulic properties, for the following reasons: (i) most agricultural
fields are selected on the basis of homogeneity in soil conditions (within
plant rooting zones); and (ii) such conditions are amenable to first order
statistical analysis which yields analytical solutions. The resulting
analytical expressions relate the variability of soil hydraulic properties
to the expected variability in matric potential and relative saturation.
Comparisons of analytical predictions with Monte Carlo*** simulations for
surface and buried sources resulted in excellent agreement. The
expressions may be used to define regions with smaller uncertainty for
better monitoring, or for determining the minimum number of sensors
needed to obtain estimates with a prescribed estimation error.

* skillful in aiming, to guess at
** a statistical measurement
*** a statistical model using random fields, analytical flow calculations and
expected values
******************************************************************************
***************

This research paper involves a sophisticated way to assess how many sensors
and where should they be placed in the field due to field variability.

1) Where do you place your sensors (neutron probe, tensiometers, etc.)
relative to the drip emitter?

2) For those of you in the real world of farming, how do you decide how many
sensors to put in the field?

3) Is the decision strictly economics along with trying to pinpoint the
"average" soil within a given field or do you use a model similar to the one
described above?

5) On a not too distant topic, when installing a drip system in a very
heterogeneous soil, do you place drip lines with different output and spacing
through zones which you think are atypical to the field? Or is it not worth
the hassle and install a system designed for the average soil type/condition?

Richard Mead
Soil Scientist
Trickle-L owner/manager

What are the choices for Potash fertilizer through drip? What is the
material of choice?

I use a 3-9-9, but there are fields that do not need the phosphate. I also
wish to apply the phosphate pre-plant. According to xxx (I hope I can
remember his name) of UC Davis, he said that the phosphate is needed before
planting and the plants are efficient at picking up needed P towards the
end. And P does not move. That leaves K. One chemical supplier says only
KTS (potassium thiosulfate) can make it through the tape. He mentioned
white potash (I think he is very confused).

Suggestions
Steve Jordan @ Second Foundation

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