The meeting was called to order by W-128 President, Dana Porter at 9:39 AM.
Members attending introduced themselves. Attendees included:
| Mahbub Alam | Kansas State University (Tuesday and Wednesday) |
| Brian Boman | University of Florida (Tuesday) |
| Bill Branch | Louisianna State University AgCenter |
| Carl Camp | ARS, North Carolina |
| Gary Clark | Kansas State University (Thursday) |
| Dorota Haman | University of Florida |
| Terry Howell | USDA-ARS, Bushland, Texas |
| Sal Locascio | University of Florida |
| Freddie Lamm | Kansas State University |
| Alan Lakso | Cornell University, Geneva, NY |
| Carl Motsenbocker | Louisianna State University AgCenter (Tuesday) |
| Mick O'Neill | New Mexico State University |
| Manuel Palada | University of the Virgin Islands |
| Larry Parsons | University of Florida |
| Dana Porter | Texas A&M University |
| Danny Rogers | Kansas State University (Thursday) |
| Larry Schwankl | University of California, Davis |
| Ken Shackel | University of California, Davis |
| Clinton Shock | Oregon State University, Ontario |
| Tom Spofford | NRCS (Tuesday and Wednesday) |
| Craig Stanley | Braden, University of Florida (Tuesday and Wednesday) |
Business meeting:
1. The minutes from the 2001 meeting were distributed and approved.
2. Clint is secretary and Larry Schwankl is the incoming chair.
3. A committee was appointed to find a new secretary for 2003: Freddie
Lamm, Ken Shackel, Craig Stanley, and Larry Parsons.
4. We need to start considering dates and locations for the next
meeting.
Dovetailing with another meeting was discussed.
5. We need to look at the project and decide if there should be major
changes. Clint passed along Mike Burke’s comment that the project
was in pretty good shape and needed revision, not a major rewrite.
Ken presented a case history of where plant based measurements of water status have made a difference. A grower was having a problem with almond hull splitting and differential performance on two sides of the same field.
They used carefully managed stem water potential. There were water savings on both sides of the field, and hull splitting became uniform. RDI. They ended up with very different water applications on the two sides of the field.
Larry Schwankl, University of California, Davis
A practical problem for drip irrigation is often the system is built before soil differences are accounted for. Yet the differences in the soil can often be seen. An irrigation system can be divided into different pieces, which then can be irrigated at different frequencies.
You are aware of EC, electrical conductivity. We use EM, electrical magnets were drug on the soil surface The method depends on avoiding conditions of high salinity or high soil moisture which can interfere with the measurement of soil properties. The EM and GPS/GIS allows mapping as a guide for sampling the field for EC to see what you have.
Carl Motsenbocker and Bill Branch, Louisiana State University AgCenter
Tabasco peppers have problems with fruit yield and quality. N research has been done in the past but P and K research had not been undertaken. Our long term goal is to be able to relate soil analysis to plant fertilizer requirements and fruit yield and quality. Greenhouse tabasco nutrition studies with different P and K levels are ongoing.
Tabasco pepper pungency is created by a combination of alkaloids determined by HPLC. The folk lore is that pungency is affected by water stress and there are only a few papers on the topic. Next year greenhouse studies will be conducted with different irrigation regimes to study the effect of water stress on tabasco pungency.
Currently, there are 30 acres of tabasco peppers under trickle irrigation on Avery island. Until a few years ago, none of the local crop was irrigated. Most of the crop was moved to Brazil, Honduras, Guatemala, etc. in the 1970's because of labor costs.
The LSU AgCenter Hammond Research Station is investigating the lack
of uniform distribution in drip irrigation and fertigation of
strawberries.
The Red River Research Station is comparing furrow irrigation and
sub-surface
drip irrigation of cotton. The Sweet Potato Research Station is
comparing
micro-spray and furrow irrigation of sweet potatoes. A proposal has
been
submitted to test and demonstrate sub-surface drip irrigation of
treated
sewage effluent at Camp Grant Walker.
Mick O'Neill, New Mexico State University
Current work is in collaboration with the Navajo Indian Products Industry, NAPI. This is a commercial farm set up by the Bureau of Indian Affairs, with federal funding for its infrastructure. There are 10,000 acres set up for side roll irrigation which is not being used. The area might be an opportunity for drip irrigation.
There are problems with competition with NAPI for water and treaties with the US. Also the ESI requires minimum stream flows. NAPI is also interested in selling water to Gallup, NM.
Preliminary trials with potatoes and small grains went fairly well. Local constraints for drip irrigation included rodents. Rosol (a coagulant), butyric acid, and hot pepper were mentioned in the discussion among the group as possible helpful products. There are also weed control constraints: Mick said that a more aggressive weed control program was needed.
Mick has been examining hybrid poplar clones grown with drip irrigation. Poplar could be useful as fuel wood, wastewater treatment, shredded material for filter pads, and environmental cover. Local interests are having difficulty providing materials for evaporative cooler filter pads. Of the clones tested in 2002, only NM6 and OP 367 took well. There are problems with establishment and chlorosis (high pH soil) in spite of spraying iron. Mick intends to look at a wider range of poplar clones.
Alan Lakso, Cornell University, Geneva, NY
Grape research centers around questions on whether or not it makes sense to irrigate. There is about 60 to 80 mm of rainfall in summer months. In July pan evaporation is 150-170 mm. There is a great deal of variability of water stress between years.
Trials were conducted for 12 years with balanced pruning and minimally pruned concord juice grapes. Drip irrigation was not economically justified for balanced pruned vines, but probably is with minimally pruned vines, depending the cost of development of water to the drip system.
Minirhizotron studies of root dynamics show that minimally pruning does not reduce new root production, but dry soil does reduce new root production. Roots generally grow when they can, controlled mostly by crop competition, temperature, and water availability.
We evaluated water use in apples using sap flow gauges calibrated by whole tree enclosure chambers. The crop coefficients from arid regions did not work well for New York apples as they varied from 0.5 to 1.0 of ETo.
Carl Camp, ARS, North Carolina
Carl reviewed previous drip irrigation research over many years with cotton and the problems of development of a plow pan.
Flax is a new crop, and they are trying to follow short season cotton. Trying to work out whether or not to subsoil, chisel plow, use no till, or?
Examining SDI for fairway turf. Looking at drip irrigated waste water with tapes 0.2 m deep and tapes at 0.4 and 0.8 m spacings. There are three types of irrigation water: clean, waste water, and saline water. Carl is using 96 ten by 12 foot plots.
Why use drip irrigation? Cost? Smell? Problems irrigation of special areas on a golf course that are too dry and too wet in close proximity to each other? Areas where you need to retrieve and replace the irrigation hardware.
Effluent project.
Swine waste treatment plant: should the effluent be used just to get it out of the way or to do a good job of irrigation. Trials are being run on ‘Coastal Bermuda' and crops.
SDI Bermuda grass experiment
4 Variable water sources
2 SDI line spacings, 24 and 48 inches at 8-inch depth
4 replicates = 32 plots.
SDI Soybean and Wheat experiment.
2 water sources
2 spacings
4 replicates = 16 plots
Continuous low application rates
1 water source
2 SDI spacings
4 replicates
8 plots, each 52 x 52 feet
SDI is being compared to sprinkler disposal of effluent.
Terry Howell, USDA-ARS, Bushland Texas
The irrigation of corn and soybean have thoroughly studied. Water use efficiency of SDI, LEPA, LESA and MESA have been studied. SDI and LEPA have been most successful in deficit irrigation situations.
The reason that the water use efficiency declines as you reach near full ET, is that you get more vegetative matter in the grain plant growth.
Future work: We want to look at cotton because we might be able to get a good crop and reasonable financial return with less water than the amount of water needed to grow corn or soybeans.
We are studying
1. SDI on cotton for early maturity, higher yields.
2. Permanent bed SDI for better crop establishment.
3. Irrigation frequency and amount effects on water use efficiency
as determined by soil hydraulic properties. These can be affected
by soil type, so we are working with 4 soil types.
Cotton, look at irrigation systems, herbicides, etc.
Permanent beds: maybe reduced tillage will improve fallow season soil water balance.
We are using 30- and 60-inch beds. Drip tape is placed at 0.15, 0.225, and 0.3 m depth. Can we still germinated seed from these depths in a dry spring?
We have lysimeters which allow the measurement of water balances.
Craig Stanley, Braden, University of Florida
Craig is studying caladium grown during the warm season in organic soils. Found there was no relationship between the level of the water in the canals and the soil water.
Tested water tables at 12-, 18- and 24-inch depth. When you look at caladium tuber weight on the basis soil water, the tuber weights increase with the shallow water table.
We looked as a microirrigation seepage as an alternative method of irrigation to pumping water into the canals. You are using the irrigation system to maintain the water table. The big saving was the reduction in surface runoff.
The same kind of system was used on tomatoes. When you get clogging, it does not matter very much because it is compensated somewhere else. We have one tube every 20 feet. We use much less water to maintain the same water table, e.g. 22 inches with drip vs. 56 inches using surface replenishment.
They have developed a 2-D model for estimation of water movement through a mulched bed. The model is being used for looking at water use and chemical movement.
Business Meeting: 4:42 PM
1. Craig Staley was nominated, moved and seconded that nominations
be
closed, Craig was elected as secretary 17 to 1.
2. The meeting time and place were for 2003 were discussed. The meeting
will be held October 22-24 at Davis, California. The 23rd will be
the tour.
3. The project revisions were discussed. it was agreed that not
very many folks were working on objective 3. Everyone needs to come to
the meeting with a list of what they want to do and how their work fits
into the objectives. The group agreed that we need to incorporate new
references
into the project text.
4. A discussion followed about potential new members and inactive
members.
Larry will write the members that we are revising the project and ask
folks
if they want to remain in the project. There is a real benefit in the
exchange
of ideas, and the desire to stimulate participation from all over.
5. Larry asked that members send him their reports so he could make
a consolidated annual report including presentations, publications, and
students for each state.
October 23, 2002 Field Tour
Heavy down pours interfered with part of the morning tour. The tour proceeded south along the Mississippi to the Point-a-la-Hache marsh restoration project area. The group saw microirrigation for citrus frost protection at the Racca farm at Port Sulfur and elsewhere. Cajun cooking at Ann’s Restaurant was Clint’s favorite part of the tour. The Citrus Research Station was visited.
Topics discussed during the day included frost protection, loss of wetland, salt intrusion, irrigation to combat salt intrusion, Formosan subterranean termite control, and greenhouse tomato production.
October 24, 2002 Business meeting
Larry asked that all reports of publications, presentations, and students be sent to him. State reports need to be sent to Clint Shock for posting on the web.
Discussion of the project revision
Possible title: Increased efficiency and sustainability of natural
resource systems through microirrigation.
Objectives: Volunteers for each objective.
1. Management strategies: Larry Schwankl
2. Design and components: Gary Clark
3. Decision criteria: Reasons in addition to the economics. Most of
us can contribute something. Freddie Lamm.
Many of the problems are hardware related according to Freddie Lamm.
Sal, much of the adoption is related to water availability.
4. Educational activities. Clint Shock
Everyone should send their information on what they intend to do by January 15, 2003 to the objective coordinators.
Once the objectives are done, then we will work over the rest of the project and literature review.
Who is going to take overall responsibility. Larry, Freddie and
Clint
volunteered to do it.
Sal has been working on blossom end rot of tomato. The 40,000 acres of tomato represent half the Florida vegetable value in Florida. Ca is a problem. High K and ammonium aggravate the problem.
Calcium nitrate and -10 kPa irrigation criteria were more effective in increasing fruit calcium and reducing blossom end rot. Irrigation at -25 kPa in one season resulted in water stress and extensive blossom end-rot.
The second year study with very little rainfall, we got very little blossom end rot.
Irrigation scheduling: whenever the tensiometers indicated an irrigation was needed, ¾ of pan evaporation for the day was applied. The pan evaporation amount was determined by averaging the previous 10 days.
Dorota Haman, University of Florida
1. Looking at tape performance, with the application of effluent products. Does the tape clog with cleaning treatments? Ozone, chlorine, and acid are being tried.
2. Evaluation of three different systems: spitters, overhear sprinklers, sub irrigation.
Larry Parsons, University of Florida
Use of Orlando waste water for irrigation is being examined. Orlando’s waste water disposal was contaminating a bass fishing lake. Growers rejected the water at first.
We asked what nutrient benefits are there from the use of this reclaimed water? How much water would need to be applied to meet the trees’ nutrient needs? Could the trees pick up what they need from the effluent? The effluent was applied to citrus using micro sprinklers.
Trees needed supplemental N over and above the nutrients in the effluent. P, K, and certain micronutrients were adequate in the waste water. A conclusion was that the normal N fertilizer rate still had to be applied.
Some denitrification might have been occurring for the leached N.
-10 kPa irrigation criteria.
There are now more folks wanting to use the waste water than the water available.
Manuel Palada, University of the Virgin Islands
Hot pepper is an important economic crop. Three varieties were tested at 3 irrigation criteria, -20, -40, and -60 kPa. Crop height, yields, quality, and water use efficiency (WUE) were measured.
Growth at -60 kPa was similar to the other irrigation criteria. There was a significant interaction between variety and irrigation criteria for yield and pungency. This is important since growers are paid by yield and pungency.
Effect of plastic mulch, straw mulch, or no mulch on eggplant. Eggplant was irrigated at -30, -60, and -70 kPa.
Next year we will continue to study drip irrigation on hot pepper, eggplant, watermelon, and Puerto Rican sweet pepper.
Clinton Shock, Oregon State University, Ontario
Drip irrigation systems were tested on alfalfa for seed, alfalfa for hay, potato, onion for seed and for bulbs, poplar for logs, yew, sugar beet, wheat, carrot for seed, and mint. Treatments are being evaluated based on crop yield, crop quality, and water use efficiency. Grids of sensors are being used to examine the vertical and horizontal movement of water through the soil profile from drip lines. Various soil moisture monitoring equipment is being evaluated for use as irrigation scheduling tools in growers’ fields.
Gary Clark, Kansas State University
Gary has been stretching drip tape products, then evaluating their performance. They have been looking at the load necessary to stretch the tape different amounts, then looking at emitter performance after stretching.
They also examined water temperature and discharge performance. Temperature modifies performance and with surface drip, temperature can really change performance.
Examining several types of tube with different emitters, in the 4 lit/minute flow rate class to dispose of lagoon waste water. Pressure compensating or not, designed to deal with waste water or not. How can these systems help serve cities and cattle feed lots?
Freddie Lamm, Kansas State University
We have written a MS Excel model to compare center pivot sprinkler to SDI. The economic factors depend on your assumptions. Big differences exist based on product selling prices and your assumptions on the life of the system. We assumed that you are changing from furrow to drip or sprinkler irrigation. The program is available for downloading from our web site
We are in a drought since 2000. We have had excessive temperature in the middle of summer.
We have been examining SDI vs. simulated LEPA sprinkler. There were advantages for SDI or LEPA in different years. We thought the differences were due to the broadcast fertilizer application method.
Drip line depth, the jury is still out. It will depend on the relative longevity of the system.
Irrigation frequency? Does it matter for deep rooted crops?
In 2002, less frequent SDI irrigations were more productive.
KSU has a web site dedicated to subsurface drip irrigation, http://www.ksre.k-state.edu/sdi/
Dana Porter, Texas A&M University
We examined dead cotton plants with elevated levels of Ca and B. Apparently the growers turned the water off when it rained, and toxic levels moved into the plant.
Another problem is that if we can get 15 percent more efficient, the growers expand their acreage by 15 percent. The acreage can become unmanageable.
A new drip irrigation experimental area has been developed. Drought tolerant corn is being examined through breeding. Water losses from pre irrigation has been shown to be greater than was previously assumed.
Water distribution uniformity is important for SDI.
Manganese clogging has become a problem. Manganese clogging is being
addressed by acidifying the water acid to keep the manganese in
solution,
then use hydrogen peroxide to kill the bacteria.