Archive TRICKLE-L: file log9407, part 1/1, size 48728 bytes:

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Dear Trickle-l Subscribers,

Hi! My name is Jerome Pier and I am one of the charter
members of Trickle-l. I plan on advertising the list on the two
lists I own, Soils-l and agmodels-l, but first I wanted to make
sure that the list was working. We also need to decide on a
welcome message that new subscribers will see when they receive
acknowledgement of their subscription from the listserv daemon. I
will also advertise the list on New-List and on sci.agriculture.
These four groups see moderate traffic and should be a good
source for new subscribers who might be interested in trickle
irrigation. If anyone who is presently subscribed has any
suggestions, please let me know either personally or by posting
to the list (trickle-l@unl.edu).

Sincerely,
Jerome Pier
List Owner Soils-L and Agmodels-L
jp@unl.edu

Dear Trickle-l'ers

We number six subscribers to date! That number is about
to increase rapidly, I predict. Now that I see that everything
seems to be working properly, I will advertise the list to
several high profile sites across the 'Net. New users will need
some assistance using the list so here is a helpful Welcome
Message that I would like to suggest:
------------------------------Cut Here---------------------------
****Please Keep A Copy Of This Message For Future Reference****

Welcome to Trickle-L!

This mail list is devoted to the open and
unmoderated discussion of drip and trickle irrigation. Any topic
that is related to this method of irrigation is welcome. It is
hoped that this list can be used for the exchange of information
and ideas pertaining to drip and trickle irrigation. Anyone is
welcome to join this list.

Here are some helpful pointers to making your use of this list
easier (hopefully!). First of all, ALL commands pertaining to the
list are handled by the listserv daemon and not by the list owner
or the discussion list. Commands are typically one line of text
which contains keywords which tell the listserv software to do
something. You have already performed your first listserv command
by subscribing to the list which you did by sending email to
listserv@unl.edu conatining the command:

SUB TRICKLE-L First Last

If you feel you want to leave the list at any time, send this
command to listserv@unl.edu:

UNSUB TRICKLE-L

When you are ready to post your message to all the subscribers of
the Trickle-L list, you send your email to the address
trickle-l@unl.edu. Please be careful when using this address!
Experienced mail list users often get irate when 'bandwidth' is
wasted due to improper posting to the discussion list. One
suggestion which has worked well on other mail lists is to use
your first post as a new subscriber to introduce yourself as far
as your background, area(s) of expertise and interests which
might pertain to the discussion topic. Also helpful is trying to
think of a question which might spark discussion. Neither the
introduction nor the discussion question are mandatory but they do
serve to stimulate exchange of information and ideas and keep
the list alive.

When you post your message you may not know if it was
seen by the list as a whole. This is often the cause for panic by
new subscribers. It is sugessted that you send the following
COMMAND to listserv@unl.edu to turn on automatic message
acknowledgement of your post (it will bounce back to you):

SET TRICKLE-L MAIL ACK

Once you feel comfortable with the listserver, you can reduce the
number of messages in you mailbox by turning off message
acknowledgement by sending the COMMAND to listserv@unl.edu:

SET TRICKLE-L MAIL NOACK

One of the nice features of a mail list is that it is
automatically archived on a monthly basis. This means that after
the first week of every month, a file may be obtained of all the
posts to the list for the previous month. To obtain this file,
send the following COMMAND to listserv@unl.edu:

GET TRICKLE-L LOGYYMM

where YY is that last two digits of the year and MM refers to the
two digit month code (01 for january, etc.).

To see which archive/log files are available and what other lists
listserv@unl.edu is hosting, you send this COMMAND:

INDEX

Other commands for the list can be obtained by sending this
COMMAND to listserv@unl.edu:

HELP

I hope that this information has been helpful and will make your
use of the mail list a little less confusing. Please keep a copy
of this message in a safe place for you will probably need to
refer to it at a future date. If you have any questions or need
assistance, feel free to contact the list owner, Richard Mead at
rmead@arss.arsusda.gov.

Virtually,
The Listserv Daemon
listserv@unl.edu
-----------------------------Cut Here-------------------------

Please let me know what you think about this Message and let me
correct any errors (I think the Richard's email address is
incorrect since I typed it from memory). When we agree on the
final format, I will have Chuck Sundermeier, UNL Mail Wizard, add
it to the battery of trickle-l files.

Sincerely,
Jerome Pier
jp@unl.edu

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 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

For information on who is reading what.

Name : Peter Leroy
Origin : Ground Management Systems, Sydney Australia
Research : Turfgrass breeding, Irrigation management systems, plant
condition scanning, environmental control systems.
E-Mail : peter@scgt.oz.au
General : Well aquainted with work carried out in various centres, in
particular Israel, Germany, Australia. Develop software and pcb's for
irrigation control systems and am an 'end-user'

-----------------------------------------------------------
> 1) Briefly, what is your affiliation with trickle irrigation?
Research and development of sub-surface irrigation control systems.
and the use of small bore piping for soil airation.

> 2) What crops do you use drip irrigation on?
Vegetables, cotton and experimental plots on turfgrass.

> 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.
Depending on the crop . In turfgrass 100mm in cotton 200mm. Generally below
root zone.

> 4) What problems have you encountered with subsurface drip?
Installation on broadacre areas. developing optimum moisture control systems

> 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?
under controlled conditions up to 50% reductions.

> 7) Do you have water quality problems? If so, how do you tackle the
> situation?
No

> 8) How frequent do you irrigate? Many times a day or just one long session
> per day or several days?
usually one long session. depending on infiltration rates etc.

> 9) Do you have rodent damage? If so, how do you tackle the problem?
No

> 10) Are you pleased with the uniformity of your system or systems? Were they
> designed correctly?
Yes

This note has been sent before, but is being send again just in case newer
members did not recieve it.
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? If so how by
how much?
7) Do you have water quality problems? If so, how do you tackle the
situation? (Acid injection, Chloride treatment?)
8) How frequent do you irrigate? Many times a day or just one long session
per day or several days? (high vs low frequency)
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

1) Briefly, what is your affiliation with trickle irrigation?

We have a five acre farm where one acre is devoted to apple trees and
another one and half acres is used for market vegetables and herbs. We
currently use soaker hoses on part and are switching to Netafim sprinklers.
We haven't found a low volume (<6,000') dealer for drip hose. We are in
southern Wisconsin, zone 5b although our peach trees nearly secumbed to a
few toasty -30F nights last winter. Our goal is to develop a reliable
monitoring system to automate the watering process. That would move us
beyond a timer we current use.

2) What crops or plants do you use drip irrigation on?

Corn, tomatos, lettuce, herbs. We are trying to differentiate between
"row" e.g. lettuce, carrots, potatos, and beets, and "unit" e.g. tomatos,
watermelon, and cabbage that we would like to run individual lines.

3) If using subsurface drip irrigation, what is the average depth of
placement of the drip line?

We use surface, so we can dissamble the system to rototill the mulch under
in the fall and re mulch over winter.

4) What problems have you encountered with subsurface drip?

N.A.

5) Fertigation is a real advantage of drip irrigation. What form of N, P
and K have you been trying and to what success?

Not presently doing. Our goal is an organic system. Interested in data
and trying ideas about that.

6) Have you experienced a reduction in fertilizer and water use? If so how by
how much?

N.A.

7) Do you have water quality problems? If so, how do you tackle the situation?

We soften domestic waater but not garden. Some iron, quite hard; some lime
on plastic spray heads

8) How frequent do you irrigate? Many times a day or just one long session
per day or several days?

frequency: once per day fort =/- 20 min.unless it rains (avg. ann. precip =
36" Last year nearly 2x that)

9) Do you have rodent damage? If so, how do you tackle the problem?

Ground squirrels pests but not to the system.

10) Are you pleased with the uniformity of your system or systems? Were
they designed correctly?

We are looking to fine tune the system. Doesen't seem nearly as much
support as in Europe and mid east. We designed the syetem ourselves.

Tks much for this service. Happy to test ideas.

Jim

Dear Tricklers,

My name is Jerome Pier. I am currently a Post-Doctoral
Research Associate in the Biological Systems Engineering
Department at the University of Nebraska-Lincoln. I have a B.S.
in Forestry Biology from SUNY College of Env. Sci. and Forestry,
a M.S. in Agronomy/Plant Science (Weed Science) from Cornell
College of Agriculture and Life Sciences and a PhD in Soil and
Water Science from the University of Arizona. I am currently
working on the Management Systems Evaluation Area (MSEA)
Modelling Project using the Root Zone Water Quality Model
developed by Great Plains Systems Research Unit of the USDA-ARS
at Ft. Collins CO to simulate Best Management Practices in
irrigated field corn and soybeans.
> 1) Briefly, what is your affiliation with trickle irrigation?

My interest in drip/trickle irrigation stems from my PhD
research at the Univ. of AZ. My dissertation topic examined an
improved management practice for watermelon in the arid
southwestern U.S. I looked at using plant tissue (petiole) tests
to aid in scheduling split N fertigations and irrigation
scheduling by examining tensiometers read just prior to daily
irrigation. The irrigation system was sub-surface trickle tape
(Chapin Watermatics Twin wall IV) placed at 20 cm below the soil
surface. Similar management of other vegetable crops has been
examined by researchers in the Soil and Water Science Department
at the U of AZ. I also used pressure transducer equipped
tensiometers to examine the variation of soil water tensions at
30 minute intervals under three irrigation regimes.

I feel that trickle irrigation shows great promise for the
future of irrigated agriculture where high value crops are
concerned. My research showed that exceptional yields could be
obtained while minimizing leaching losses of fertilizer nitrogen.
I look forward to participating in this discussion group.

> 2) What crops do you use drip irrigation on?
Subsurface trickle irrigation has been studied at the
University of AZ for: cotton, sweet corn, cantaloupe, watermelon,
collard greens, mustard greens, leaf lettuce, broccoli,
cauliflower. A review of the recommended management practices for
these and other crops can be found in:

Doerge, T.A., R.L. Roth and B.R. Gardner. 1991. Nitrogen
fertilizer management in Arizona. College of Ag., Univ. of AZ.
Publication 191025, Tucson AZ.

> 3) If using subsurface drip irrigation, what is the average depth of
> placement of the drip line?

Our drip tape was placed at 20 cm depth. However, this
was for our research and the system was removed at the end of
each growing season. If the system was to be 'permanently'
installed, a depth of 30 cm or greater would have been preferable
since tillage operations would interfere with a more shallow
placement.

> 4) What problems have you encountered with subsurface drip?a

Salt accumulations and salt stress/injury of seedling
watermelon and cantaloupe.

> 5) Fertigation is a real advantage of drip irrigation. What form of N, P and
> K have you been trying and to what success?

N was applied as Urea-ammonium nitrate (32% N).
Phosphorus was applied a phosphoric acid. No K fertilizer was
applied. Sulfuric acid was applied for emitter maintenance as
well as S for crop growth. UAN-32 is a very good form of N
fertilizer for our system. It was readily available and provided
immediate N in the form of nitrate as well as delayed N from the
hydrolysis of urea to ammonoium and then from ammonium to
nitrate.

> 6) Have you experienced a reduction in fertilizer and water use?

By using tissue testing to schedule 5 split applications
of N, it was determined that 100 kg N /ha would produce
watermelon yield that was more than twice the state average while
minimizing leaching losses of N. No numbers were available for
amounts of water and N used by farmers in AZ for watermelon
production but the typical farming practice for watermelon is
furrow irrigation with N applied in the irrigation water.
Imagine...

> 7) Do you have water quality problems? If so, how do you tackle the
> situation?

The irrigation water was not highly saline but did have
appreciable levels of calcium. Sulfuric acid was applied on a
regular basis to clear calcium from emitters.

> 8) How frequent do you irrigate? Many times a day or just one long session
> per day or several days?

Irrigation occurred once per day for anywhere from 20
minutes to 5 hours depending on the stage of the crop, the
tensiometer readings prior to irrigation and the irrigation
treatment desired.

> 9) Do you have rodent damage? If so, how do you tackle the problem?

No.

> 10) Are you pleased with the uniformity of your system or systems? Were they
> designed correctly?

Our system was quite uniform but it must be understood
that our drip tape was only 50 feet long in each plot and the
mains were 2 " in diameter. Nevertheless, longer runs would not
have been a problem.

Sincerely,

Jerome Pier
jp@unl.edu

To balindem@facstaff.wisc.edu regarding scheduling of irrigations:
Some suggestions:
1) Evaporation pan used in conjunction with known crop coefficients
2) ETgage atmonometer, which is becoming popular, it is a little more
maintenance free. I have the manufactur's address if you're interested.
3) There is an interesting article in the July '94 issue of Landscape and
Irrigation magazine (Vol. 18, Num. 7) on soil sensors. It's geared toward
landscaping, but a plant is a plant...right??
Sincerely,

Richard Mead
List owner

Dear Jerome,
Regarding:> 7) Do you have water quality problems? If so, how do you tackle
the
> situation?
The irrigation water was not highly saline but did have
appreciable levels of calcium. Sulfuric acid was applied on a
regular basis to clear calcium from emitters.............
Did you find it difficult to handle the sulfuric acid? Have you heard of
N-pHURIC acid, which is easier to handle and maybe a tad bit more effective?
Just curious.....
and...> 8) How frequent do you irrigate? Many times a day or just one long
session
> per day or several days?
Irrigation occurred once per day for anywhere from 20
minutes to 5 hours depending on the stage of the crop, the
tensiometer readings prior to irrigation and the irrigation
treatment desired.......... We at the Water Mangement Research Lab recommend
through (trial and error) that high frequency ( that is many times a day) is
better for fertilizer and water uptake.
If there is an 8 mm day, we will apply 8 irrigations at 1 mm per session. Of
course this is research and we have sophisticated remote sensing devices
(lysimeters) to trigger the irrigations, but a farmer could obtain a timer
with these capabilities.
Thanks for your input Jerome!

Richard Mead
List owner
USDA-ARS-WMRL

Just a note to all members....we are now up to 74 members of Trickle-l. The
growth is faster than we expected. The list now is a little more than a week
old. Again, welcome. If one wants to see this list of members simply address
the following command to listserv@unl.edu: rev trickle-l
I hope everyone has recieved a welcome message and the 10 question survey. If
not, please let me know.
There seems to be a bit of shyness on the net in this group (either that or
we're all very busy with other things). Please respond to the survey to get
the ball rolling. I notice we have a very diverse group which should make
things even more interesting. If you know of friends that use computers and
would be interested in our group, please feel free to invite them to
subscribe.
Thanks for your participation!!!!!!

Richard Mead
List owner
USDA-ARS-WMRL

Greetings - My name is Clint Morse and I manage the greenhouses for the
Ecology and Evolutionary Biology here at UCONN. We have over 4000 diverse
species of plants jammed into 10,000 sq feet of greenhouses. Any type of
automated irrigation would be nice but with virtually every plant having
different soil mix and water requirements - this is a tough thing to pull
off. Heres hoping this forum yields ome clues.
I just signed on to this list and have been recieving a bunch of messages
but have not seen the indicated survey or welcome message. I just got back
from the International Greenhouse Conference ACE-SYS in NJ and may have
missed it somewhere.
Also - Richard Meads' comment on the soil sensor for landscaping that a
'plant is a plant, right?' is true but soil is not soil - Many sensors that
are designed for 'soils' do not function too well in soilless mixes - It
might work, but just so any novices do not get stung - test them first in
your situation.
Later...Clint Morse

>
> Dear Jerome,
>>> 7) Do you have water quality problems? If so, how do you tackle
>>> the situation?

>> The irrigation water was not highly saline but did have
>> appreciable levels of calcium. Sulfuric acid was applied on a
>> regular basis to clear calcium from emitters.............

> Did you find it difficult to handle the sulfuric acid? Have you heard of
> N-pHURIC acid, which is easier to handle and maybe a tad bit more effective?
> Just curious.....

We had plenty of gallons of conc. H2SO4 lying around for
lab procedures so that is why we used it. I have heard of
N-pHuric acid but have no experience with it.

>>> 8) How frequent do you irrigate? Many times a day or just one long
>>> session per day or several days?

>> Irrigation occurred once per day for anywhere from 20
>> minutes to 5 hours depending on the stage of the crop, the
>> tensiometer readings prior to irrigation and the irrigation
>> treatment desired..........

> We at the Water Mangement Research Lab recommend
> through (trial and error) that high frequency ( that is many times a day) is
> better for fertilizer and water uptake.
> If there is an 8 mm day, we will apply 8 irrigations at 1 mm per session. Of
> course this is research and we have sophisticated remote sensing devices
> (lysimeters) to trigger the irrigations, but a farmer could obtain a timer
> with these capabilities.

We were manually applying three seperate irrigation
treatments (to maintain 12, 7 and 4 kPa soil water tension just
prior to the daily irrigation). Therefore, it was easier to
schedule irrigations for one application per day. I have no doubt
that the use of a control sensor (I would use a pressure
transducer equipped tensiometer) to initiate irrigation would
cause more frequent applications to be applied and there would be
better control of application amounts with less deep percolation
beyond the root zone. It was hoped that our research would
indicate what soil water tension provided optimum yields with
minimum leaching. We felt that between 7 and 10 kPa soil water
tension at 30 cm depth just prior to the onset of irrigation was
the best.
> Thanks for your input Jerome!
>
Mon Plaisir!

Jerome Pier
jp@unl.edu

> Richard Mead
> List owner
> USDA-ARS-WMRL
>
>

From: Craig Thompson LodiCraig@AOL.com
RE: Scheduling methods

Our experience with grapes has show tensiometers don't give us adequete
information in the early season with low moisture tension. Moisture blocks
have been similiar, and have been subject to variation when we fertigate ...
fertilizer causes a them to falsely indicate that the soil is wetter than it
is.

Neutron probes (we employ a service) have proved dependable and repeatable.

California has the California Irrigation Management Information System
(CIMIS), which consists of a series of multi-sensor weather stations at
stragic location throughout the state. With periennial crops like our
grapes, I expect we will be able to correlate our neutron probe data, and
rely entirely on the CIMIS data in the future. The calculated
Evapotranspiration Coefficients (ET) corrected for the crop (ETc) are proving
to be very accurate, allowing us to manage our water needs much like our
checkbooks (Water Budget Method). I am not sure if any other states are
conducting similiar programs, but if not, the data is readily available ...
and a system could be operated by one large grower, or cooperatively by
smaller growers for very accurate water management. The hardest part is
refining the Crop Coefficient for each particular field and variety ... once
determined, it seems to be accurate from one year to the next when indexed to
growth stages (not to the calender). ET data also is easy to collect by
computer, and will potentially facilitate hands of corrections to the
irrigation cycles daily or weekly ... however you like.

Craig ... California

From: Craig Thompson LodiCraig@AOL.com

We have though long and hard about irrigation frequency. I ran both long
cycle (weekly applications) and short cycle (daily applications) with our
surface drip. Without question we get a much greater growth response with
short cycle ... even though evap losses may be higher.

> Irrigation occurred once per day for anywhere from 20
>minutes to 5 hours depending on the stage of the crop, the
>tensiometer readings prior to irrigation and the irrigation
>better for fertilizer and water uptake.
>If there is an 8 mm day, we will apply 8 irrigations at 1 mm per session. Of
>course this is research and we have sophisticated remote sensing devices
>(lysimeters) to trigger the irrigations, but a farmer could obtain a timer
>with these capabilities.

You may want to take into account the time it takes to charge the system and
gain full distribution uniformity. Our system take about 8 minutes to
stablize. In very rough terms, we are down to 90% D.U. with a one hour
cycle, and approach a 60% DU with 1/2 hour cycle times. Of course, we are
utilizing 600' runs, irrigating 40 acres square from a center main line. For
that reason, I will delay the next cycle until at least one hour of
irrigation is required.

In regards to N uptake, I have seen some data that indicates that plants have
the ability to store N, and that the difference between weekly or daily
applications may be minimal.

Regarding K uptake, I am debating with other the potential value of longer
cycle surges of K ... as we have soils that like to grab and hold on to K.
The idea being, if you wait and overwhelm the soil with K for a short time,
the plant may be able to grab more before the soil returns to equilibrium. I
would be interested in input into this matter. At what point does Potassium
get grabbed and become less available.

Craig ... California

From: Craig Thompson , LodiCraig@AOL.com

Clint Morse of Ecology and Evolutionary Biology at UCONN stated:

>We have over 4000 diverse
>species of plants jammed into 10,000 sq feet of greenhouses. Any type of
>automated irrigation would be nice but with virtually every plant having
>different soil mix and water requirements - this is a tough thing to pull
>off. ...
> Many sensors that are designed for 'soils' do not function too well in
soilless mixes - It
>might work, but just so any novices do not get stung - test them first in
>your situation.

Clint: As far as I am concerned, those sensors don't function that well in
soil either. Back in the days of surface irrigation they were fine as 'set
points.' Now, with refined and accurate surface and subsurface drip we have
the abiliy to maintance growth stage specific moisture balance in the soil
... the right thing at the right time.

The solution for your situation is easy and do-able, albeit expensive. As a
green house your plants are potted. Put plants or groups of plants on scales
and waa - laah you have a lysimeter ... feed back irrigation cycles to
changes of weight indexed to growth stage. The sheer numbers of treatments
you are dealing with would be somewhat overwhelming and would be expensive in
valving and computing. On the other hand, the rewards of quantification and
repeatability could be worth the investment.

Craig

busy is the problem, I have my own apple-crop-list and 15 research projects
underway as well as 200 fruit growers in 3 counties, so... will get
to your survey soon?
win
***********************************************************************
cowgill@aesop.rutgers.edu
aka
Win Cowgill

Professor
Area Fruit Agent
County Extension Department Head for
Rutgers Cooperative Extension of Hunterdon County
NACAA Northeast Director

Extension Center 908-788-1344 Work
4 Gauntt Place 908-806-4735 Fax
Flemington, NJ 08822-9058 USA 908-782-4141 Home
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Yes indeed, too busy to answer the questionnaire! (The busiest time of
year, you know)

I am excited about this list, as it seems to have at least a few members
interested in irrigation scheduling.

I am not a farmer, but a grad student at U.C. Davis working on a Ph.D. in
Ag. Engineering. Briefly, I am interested in developing a means to
schedule irrigation of vineyards based on a micrometeorological approach
to _crop_ (not soil) water status estimation. Although simple ET
estimates do the job in many circumstances, in grapes (winegrapes
primarily) it is desirable to stress the vines during some stages of
fruit development. Drip irrigation provides this ability nicely, but most
growers are hesitant to monitor vine water status directly (time factor
mostly, I presume).

Anyway, I am trying to get past the CWSI "big leaf" approach to water stress
estimation by more adequately modeling the energy budget of a vineyard,
including the physical canopy structure, stomatal physiology, and
transport of energy and water vapor through and above the vineyard
canopy. And, yes, I am making extensive measurements (not just an
intellectual excercise).

Nuff said for now. Hope to have the opportunity to engage in discussion
from researchers and growers interested in this area.

Mark D. Greenspan
mdgreenspan@ucdavis.edu
University of California, Davis
Agricultural Engineering / Viticulture & Enology

,

> for people to respond to: (It is not necessary to answer all questions).
>
> 1) Briefly, what is your affiliation with trickle irrigation? None, as a
researcher. I have a ranch in central Texas that I would like to grow some
pecan trees on. Presently we have about 25 mature trees (native) on an
area where I can harvest them. I would like to add soem different varieties
on about 15 acres of reasonally flat land.
> 2) What crops or plants do you use drip irrigation on? pecan trees
> 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. Back in my younger days in west Texas, I remember
planting trees with a large pipe(12 diameter) three feet into the ground next to
the trees. The idea was to fill the pipe every day or so.
> 4) What problems have you encountered with subsurface drip? never tried it.
> 5) Fertigation is a real advantage of drip irrigation. What form of N, P and
> K have you been trying and to what success? with the pecan trees, this is
probably not so much an issue.
> 6) Have you experienced a reduction in fertilizer and water use? If so how by
> how much?
> 7) Do you have water quality problems? If so, how do you tackle the
> situation? (Acid injection, Chloride treatment?)
> 8) How frequent do you irrigate? Many times a day or just one long session
> per day or several days? (high vs low frequency)
> 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

My real reason for signing up for this list is to get ideas for my pecan trees.
I have a creek next to the orchard that I can use. My brother-in-law, a
long time ago, was talking of using a large tank (10,000 gallons) on a stand
to drip irrigate vegatables. I was thinking of trying the same idea. That
is, use a ram pump or small solar pump to pump into a large tank, either on a
stand or up the hill, then let gravity feed the drip system. My requirements
are not many moving parts and not a lot of technology that must be kept
tuned. Some of my questions are; how much pressure do I need for the drip
system to work, how is the best way to to irrigate, surface or sub_surface.
See above for my experience.

Any help would be appreicated.

Jeff McSpadden
jeff@mpd.tandem.com

Normal pressures for drip (surface and surface) range from 15 to 20 psi.
There are some pressure compensating emitter systems out there that can
accomadate a normal range of flow from 10 to 30 psi.
On your pecan trees, I would suggest subsurface drip. Pistachio growers are
going to subsurface here in California and having good success.

Richard Mead

For those members who missed the welcome message (which has since been sent
out twice) please notify me personally at either: MEAD2513@aol.com or
RMEAD@ASRR.ARSUSDA.GOV.

Thanks!

Richard Mead
list owner

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
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