Report Information:

  • Annual Meeting Dates: 11/17/10 to 11/19/10
  • Period the Report Covers: 10/2010 to 09/2010
  • Date of Annual Report Publication: 1/06/2011


Meeting Minutes:

Wednesday, November 17, 2010

The 2009 meeting was organized in Ames, Iowa. Roman-Paoli, Chair, called the meeting to order at 8:05 am with a welcome and introduced the new administrative officer Dr. Steve Loring. Steve Loring introduced himself as the new adviser for the group and conveyed greetings from LeRoy Daugherty, the former advisor. He also shared his thoughts about the future funding situations that may come up and talked about the new AFRI grants. Ken Shackel, CA, asked to talk about the objectives of the project and Clint read them out for the group. The group was informed that a field trip was organized to a water treatment facility and a wild life refuse land conversion project.

Dana Porter, TX, shared the report from Texas on behalf of all researchers on low pressure microirrigation system and talked about the distribution uniformity for different types of drip lines under different pressures. She also talked about evaluation of soil water sensor for irrigation measurement, cotton response to subsurface drip irrigation interval and field topography and farm scale comparison of drip to center pivot center. Most of the information is also available on the web-site. She also talked about the Technology Transfer efforts in Texas. She also showed web-based tools for ET estimation, irrigation training programs and trainings for technical service providers, youth, and landowner guide, reference manuals and workshop series on several important topics related to irrigation management. Craig Stanley from Florida suggested looking at the milestones of the group sometime during the meeting. He then talked about his research on water use for strawberry. Last year there were 11 straight days with temperature below 310F and resulted in widespread sinkhole development. He talked about the strategies (intermittent irrigation, reduced irrigation, alter transplant type) to reducing water use during transplant establishment. He reported method where irrigation was run as 10on/10off produced best results with respect to physiological parameters. He also presented information on Florida onsite sewage nitrogen reduction systems and various studies currently underway. Several different filters and engineered media were tried for nitrogen removal by initial nitrification and subsequent denitrification. He also presented the results from Santos Bielinski on potential of high tunnels on strawberry growth, yield and quality under different irrigation systems. In general harvest was earlier and total production higher under tunnel.

Freddie Lamm, KSU presented information from paper to be presented at Irrigation conference in Arizona. He talked about the growth of SDI in the US that is about 59%, design and installation challenges, spacing of driplines, operational and maintenance challenges. A question was raised about the trust level of growers on using SDI, how to monitor, check the system and need for developing some indicators. Possibility of using salinity sensors to monitor soil water distribution was also discussed. He also informed the group that a paper on the status of subsurface drip irrigation will be presented shortly during irrigation conference.

Ali Fares, Hawaii, talked about nitrogen and water best management practices for sweet corn under conventional and conservation tillage system for Tropical Hawaii by doing a nitrogen budget and water budget. Soil moisture sensors, suction cups, tensiometers, and CO2 emissions were recorded from each plot arranged in a RBD. He informed the group that the soil classification is similar to the standard USDA classification however characteristics are fairly different. This is an on-going study and soils behave just like sand and drains quickly. The experiment involves use of several different devices that can record continuous or periodic soil water content and soil water potential across experimental plots.

Amy from ISU talked about the sensitivity of soil moisture capacitance sensors in the laboratory for nitrate ion. Results showed that sensors were more sensitive to the nitrate ion than chloride. Iowa is also trying to design a wireless sensor for soil moisture content measurement. At present there is a wireless sensor commercially available and known as "TURFGUARD" and this sensor is being used by NMSU researchers.

After lunch, format of the report was discussed with the group. In addition, minutes, short term outcomes (quantitative measurable), output (tangible, intangible: presentations and publications), activities (field work also), milestones, impacts (actual or potential) were also briefly discussed. A new member, Axel Garcia from University of Wyoming, introduced himself. He talked about some of the research facilities including irrigation systems in his Institution. His research focus is irrigation scheduling methods. Ken Shackel spoke about various remote sensing techniques (RSET and SEBEL) for monitoring ET and biomass. SWP related very well to VPD. RSET model provides a good relationship between different ETs. RSET Kc and eddy covariance Kc were poorly correlated. Good correlation between remote ET and measured ET, poor correlation between measured and remote sensed Kc. Neither Kc showed a clear response to mild stress. He further reported some of the warping issues related with the satellite images. Discussion was mostly centered around the problems and advantages associated with the remote sensing methods.

The milestones for 2010 and 2011 were discussed and participants under various milestones were identified. The next year meeting location was also discussed and some possible locations suggested include Las Cruces, NM; El Paso, TX, Albuquerque, NM; San Diego, CA, and Phoenix, AZ.


Thursday, November 18, 2010

Elvin Roman-Paoli called the meeting to order at 8:25 am. Manoj Shukla from New Mexico presented report on nitrate and chloride loadings to the groundwater, irrigation efficiency, leaching fraction and effect of salinity on Pecan bud break. He also presented the work of Dan Smeal and Mike O'Neal on gravity irrigation system and Poplar production in Farmington. Deficit irrigation was discussed and group was told that the actual amount of water applied is smaller than the total water applied to maintain nonstress conditions.

Howard Neibling from Idaho presented his work on the effect of distance from point source on yield of crops. Effect of tillage and irrigation on different crop parameters were assessed for different varieties of corn and water treatments both amounts (ET) and at v6 stage of corn growth. Soils were highly variable and soil water content followed similar trend. Discussion was mostly centered on the soil variability and irrigation using sensor reading.

Elvin Roman-Paoli from Puerto Rico talked about the microirrigation, fertigation and management trials for different fruit orchards grown on different types of soils. Different irrigation and fertilizer types and levels were assessed with respect to yield. Preliminary results did not show significant differences between Brix content or yields with different fertilizer systems. Another project soon to start will study the effect of Citrus root stocks and microirrigation levels on Citrus.

Clint Shock from Oregon talked about SDI field trials, sensor calibration field trials, and technology transfer. SDI trails were on Corn lily. Another study was on trips suppression due to water amounts. Yield was significantly related to soil water potential, symptoms and viruses were not related to SWP. Calibration of GMS and other sensors had problems with both clay and sand. The technology transfer included watershed education, organization of workshops and field days and publication of brochures on irrigation scheduling.

In the afternoon a field trip was organized to a wastewater treatment facility in Des Moines. The wastewater facility essentially removes nitrate from the surface water. The facility also records a number of other water quality parameters. The second trip was to a Prairie Education Center and wildlife refuse center located just outside of the city. The facility displayed how much soil erosion has taken place since the settlers moved in the area. The area is restored as close to its original topography and land use as possible and at present there are a number of wild animals living in the Prairie under natural conditions.


Friday, November 19, 2010

The minutes of the 2009 meeting were discussed and approved unanimously. The deadline for submitting individual state reports is set as December 20th. Manoj Shukla, Secretary, was asked to send a reminder to the group around December 10th, 2010. Axel Garcia from University of Wyoming was unanimously elected the Secretary of W2128 for year 2011. The tentative date for the next meeting was proposed as November 16-18, 2011. It was decided to setup a Doodle so that W2128 participants can vote on the 2011 meeting location. A suggestion was made to include different cities to provide voters with some options and a space can be provided for placing the comments with regard to attendance confirmation, etc.

A discussion on putting state reports/presentations on W2128 web-page took place and the members decided unanimously that a pdf of individual presentations can be uploaded on the website. The members decided that everyone will send his/her pdf of the presentation to Clint by December 15th. It was also decided that the executive committee will make a final decision on the location of the next meeting. A vote of thanks was unanimously passed for the Vice Chair for all the legwork leading to the organization of this meeting.



Objective 1: Compare irrigation scheduling technologies and develop grower-appropriate scheduling products.

In Iowa, laboratory tests of the performance capacitance-type soil sensors (EC-5 and EC-10, Decagon Devices) were completed. The experiments tested use of the sensors in tracking both soil water content and pore water nitrate concentration. Experiments to determine the conductance of aqueous solutions with various nitrate concentrations at a larger range of frequencies (0.01 to 10000 KHz) were also completed. Also in Iowa, an experiment documenting the extent to which the presence of dew on a plant canopy interferes with remotely sensed estimates of soil moisture in the L-band microwave region was completed.

In Texas, workshop series presenting results and recommendations of statewide assessment of ET Networks for regulatory and research audiences were held on July 21, 2010 (Austin, TX); August 26, 2010 (Bushland, TX); and September 13, 2010 (College Station, TX). Recommendations have been submitted to the Texas Water Development Board.

In New Mexico, field calibration of TDR sensors was carried out at three locations under sandy loam and silt loam soil. Soil samples were taken at depths of 20, 40, 60 and 80 cm from soil profiles near the CS616 TDR sensors and bulk density and gravimetric water contents were determined. At each site, new coefficients C0, C1 and C2 for Topps equation were derived separately by tree and depths using a least-squares optimization approach. The coefficient of determination (R2) was always > 0.85 between the gravimetrically and TDR measured volumetric water contents. These results were presented during annual national and international meetings.

In New Mexico, a 2 dimensional (2 D) volume balance ellipsoid irrigation model was developed for scheduling irrigation for a trickle line source irrigation system and results were compared to field experiments on onions and chile. The results of the 2 D model were also compared to a one dimensional (1 D) volume balance irrigation scheduling model.

In Oregon, irrigation scheduling instruments that measure soil water tension (SWT) are being calibrated in a hanging, weighing lysimeter in a controlled temperature growth chamber through wetting and drying cycles at different temperatures. Tensiometers, granular matrix sensors (GMS), hybrid sensors, thermocouple psychrometer readings, and capacitance probes are being compared and calibrated. Irrigation scheduling instruments that measure SWT are being calibrated in coarse sand in a crop production field with variable temperature through wetting and drying cycles created by irrigation events. Tensiometers, GMS, and capacitance probes are being compared and calibrated. Various GMS installation methods potentially appropriate for sand and clay are being tested. Irrigation scheduling instruments that measure SWT are being calibrated in heavy clay in a crop production field with variable temperature through wetting and drying cycles created by irrigation events. Tensiometers, GMS, and capacitance probes are being compared and calibrated.

In Kansas, research continued on evaluating the effect of early season water stresses on corn production. Results thus far are indicating that early season water stresses can be tolerated without yield detriment provided that the yield component of kernels/ear is not reduced and that post-anthesis water management is not deficit.

In Oregon work continued on developing grower-appropriate scheduling products. The response of corn lily (Veratrum californicum) to SWT based irrigation criteria is being studied. Corn lily is being grown with automated drip irrigation at SWT criteria of 5, 10, 20, 30, 40 kPa (4 replicates each) at both 2,150 and 4,900 feet elevation in Oregon and Idaho, respectively. Irrigation criteria is being examined for seed production of 20 native perennial plant species that the US Forest Service and BLM have determined would be highly desirable for rangeland restoration. Each species is being grown under SDI in replicated plots with three irrigation treatments (0, 100, and 200 mm/yr total irrigation) repeated over years. These results from Oregon are being communicated to growers by means of field days, workshops, grower meetings, written and on line reports, and published and on line extension brochures.

In Puerto Rico, work continued on the beneficial effect of satisfying pineapple water needs by using drip irrigation and fertigation and a poster was presented at the Caribbean Food Crop Society Annual meeting at Boca Chica Dominican Republic. Collaborative work with the University of Alabama continued with the objective of creating a remote sensing product for estimating radiation for Puerto Rico. The 1-km resolution product is valuable for estimating evapotranspiration. The remote sensing research related to evapotranspiration has a great potential to benefit irrigators in Puerto Rico. The remote sensing product provides a resolution which is orders of magnitude greater than what we have had available in the past. Future work will expand the product from the U.S. Virgin Islands to Haiti, and will incorporate a soil water budget calculation. In Puerto Rico, collaborative work is also underway on the preparation of irrigation manual including overhead irrigation, microirrigation, animal waste management and design adaptable to the Puertoricans conditions.

In New York, Geneva, previous research has shown that crop coefficients based on grass reference from arid zones are not valid for apples in humid zones. Therefore, an apple-specific Penman-Monteith (P-M) equation was developed. To provide locally-validated estimates of water use for irrigation scheduling, the apple P-M equation has been programmed into the daily calculations of the Northeast Climate Center at Cornell University to provide daily crop basal ET based on weather inputs from stations in apple-growing regions of NY. Research irrigation trials in commercial orchards are being established to validate this method. Development of a microfludics-based microsensor for continuous monitoring of plant stem potential Perennial fruit crops have extensive and deep, but erratic root systems so soil moisture measures are problematic. Additionally, to improve fruit quality growers may use deficit irrigation to impose a controlled water stress. To allow continuous monitoring of plant water stress, we have developed a microtensiometer (size about 1x3 mm) designed to embed in the trunk of perennial plants and directly measure stem water potential. Using nanofabrication prototypes are being assembled for controlled testing and initial plant embedding.

In Florida, microirrigated strawberry production uses overhead irrigation for transplant establishment. This practice typically uses very large quantities of water. A study was conducted to utilize cycling of applications to reduce amounts utilized. Equipment to control overhead sprinkler irrigation cycles were installed in a commercially cropped area. Control of the desired cycles was achieved by delineating plot areas bordered and irrigated by 4 sprinklers (48 ft x 48 ft) and installing solenoid valves below the sprinkler heads. These solenoid valves in each treatment area were controlled by a continuously cycled 1-hour time which had the ability to turn water on or off at 1.25 minute intervals. The proposed cycle times included in the original proposal were modified because of grower concerns that some off times were too long. Actual application on/off cycle treatments used were: 1) 10 minutes on/10 minutes off (50% reduction) ; 2) 5 minutes on/ 5 minutes off (50% reduction); 3) 5 minutes on/10 minutes off (67% reduction); and 4) continuously on. Establishment treatments were initiated on October 3 and terminated on October 17, 2010. Each day the water was applied during a 10 hour/day period. Applied amounts for each treatment 1, 2, 3, and 4 were 10.92, 10.92, 7.14, and 21.84, respectively. In addition to determine the effect on transplant growth among treatments, foliage harvests were made on 16 plants per treatment on October 29, 2010. Significant differences were detected between Treatment 1 and all other treatments for leaf fresh weight, leaf dry weight, leaf area and number of tri-foliates. No differences were detected among treatments 2, 3, and 4.

In California, ET measured by eddy covariance over two almond orchards in 2009 was compared to ET measured by SEBAL (satellite) to determine whether either could be used as a measure of plant water stress (or stem water potential), as measured by the pressure chamber. Meetings to discuss these results with cooperators in California and Minnesota are scheduled for 12/22/10 and 1/20/10. Preliminary results were presented at the almond industry meetings on 12/9/10 and will be presented at a CE irrigation short course on 12/17/10.

Objective 2: Develop design, management and maintenance recommendations

From Kansas, a paper was presented at the ASABE/IA Fifth Decennial National Irrigation Conference concerning the status of subsurface drip irrigation in 2010 from a national perspective. In this paper, the multiple authors from across the US described design, management and maintenance issues in their region with the goal of identifying commonalities and specific research needs. Key issues were rodent damage and uncertainties of performance as perceived by producers.

In Idaho, data collection continued this year using Decagon ECH2O data loggers with soil water sensors at depths of 15, 30, 45, and 60-cm on a number of alfalfa fields in sandy and silt loam soils. Work is on-going on water use based on actual irrigation timing and amount, and the resulting soil water content will be compared to estimated water use based on initial and final soil water content and AgriMet estimated daily ET.

In Oregon, Drip, sprinkler, and furrow irrigation systems are being compared and various irrigation criteria are being tested for their effects on onion yield and grade. Results are being communicated to growers by means of field days, workshops, grower meetings, written and on line reports, and published and on line extension brochures.

At Farmington, NM, several emitter outputs of a rigid PE dripline and a drip tape at different pressures (10 psi and gravity-fed 2.5 psi) were compared. Mean emitter outputs of these products were at 0.36 gph for the drip tape and 0.50 gph for the rigid PE, respectively at 10 psi but decreased by more than 80% (to 0.05 and 0.09 gph, respectively) at 2.5 psi. Output uniformity decreased with lower pressure in the drip tape but was unaffected by pressure in the rigid PE. Research is currently on-going to evaluate the emitter-output vs. pressure variability of several point- source emitters.

Objective 3: To reduce existing water and nutrient management barriers associated with microirrigation.

In TX, research-based recommendations have been developed for fertility management of subsurface drip irrigated cotton in the Texas Southern High Plains. Additional information will be assembled to develop and expand recommendations for additional crops and conditions.

In Colorado, research was carried out to determine the effects of using high salinity ground water on muskmelon yield and quality. In a two year study, muskmelons drip-irrigated with irrigation water with an Ecw of 2.8 dS m-1 had equivalent yields as those irrigated with 1.0 dS m-1 water. Fruit quality as measured by percent brix was not significantly different between treatments. Salt distribution patterns in the soil profile were also determined.

In Kansas, research began on evaluating the effect of nitrogen fertigation through subsurface drip irrigation on corn with three timings of N application and two irrigation levels. The goal of this research is to evaluate if carefully timed nitrogen application will maximize the yield component of kernels/ear.

In New Mexico, soil samples were collected from two onion fields under drip and furrow irrigation systems and were analyzed for NO3-N and chloride concentration for two consecutive onion growing seasons. The total amounts of N fertilizer applied to furrow and drip irrigated fields were 383 and 292 kg ha-1, and total water applied was 95 cm and 81 cm, respectively. Nitrogen application and use efficiencies were low during both seasons because of high levels of available N in the root zone due to the application of excess N fertilizer as compared with the total amount of N taken up by the onion plants. Similar leaching fraction of 0.17 was obtained during both the growing seasons using chloride tracer technique, therefore, irrigation efficiencies (1-LF) under both seasons were also the same (83%). Nitrogen application and use efficiencies were low during both seasons because of high levels of available N in the root zone due to the application of excess N fertilizer as compared with the total amount of N taken up by the onion plants. Water application efficiency increased from 77% during 2006-07 to 84% during 2008 as comparatively less amount of water was applied during 2008. In an another on-going study in New Mexico, Pecan roots were planted in pots and were drip irrigated with solutions of EC ranging from 1.5 to 8 dS/m. The project aims to evaluate the effects of different salinity levels on physiological properties of Pecan roots including bud break. Initial results show early leaf scorching in plants irrigated with saline solution having higher EC. No budbreak and subsequently leaves were observed in the second year plants irrigated with >5 dS m-1.

Objective 4: No activity is reported for this period


Impact Statements:

  1. Surveys of participants conducted by TX in the workshop, Effective and Efficient Irrigation in Cotton Production, held in New Orleans, LA January 5, 2010, indicated very favorable response to the educational quality and content of the event. Overall increases in knowledge (by category/topic) were indicated in survey responder self-assessment indicators. Surveys also indicated very high percentages of intent to adopt efficient irrigation technologies and best management practices addressed in the curriculum and workshop events.
  2. Research from Colorado shows that high salinity ground water can be used to successfully grow muskmelons with a well-managed drip irrigation system. Both yields and quality of muskmelons were not significantly influenced by the use of higher salinity ground water source compared to a lower salinity surface water source.
  3. Research from Iowa shows that using capacitance sensors operating at two different can probably allow for simultaneous sensing of soil water content and pore water nitrate concentration. Off-the-shelf soil moisture sensors operating at 5 MHz and 70 MHz showed a weak but statistically significant nitrate signal when used together. Results of tests of aqueous solutions suggested that it will be possible to hone in on the breakpoint in sensor operating frequency, below which the sensor responds to soil moisture and the nitrate ion concentration specifically, and above which the sensor responds only to soil moisture. This will likely allow for the development of a dual-frequency sensor with ion-selective or species-specific sensing capabilities (for example, sensing nitrate only, rather than ionic concentration from all ions together), allowing for the simultaneous monitoring of soil water content and soil water nitrate status/movement.
  4. Earlier research in Kansas has identified situations in corn production under subsurface drip irrigation where the number of kernels/ear is negatively affected resulting in yield decreases as much as 1 Mg/ha as compared to some types of sprinkler irrigation. Research such as being conducted in this project can identify the rationale behind these yield reductions and devise strategies to avoid them.
  5. In Kansas, the identification of rodent damage and perceptions about subsurface drip irrigation performance uncertainties as key issues across the entire US is important for increasing SDI adoption. The development of procedures and publications to address these issues can be a good focal point for a portion of the project.
  6. In Oregon, irrigation scheduling by soil water tension allows growers to use water more precisely. Calibration of soil moisture instruments promotes improved irrigation scheduling with greater precision and confidence.
  7. In Oregon, better use of irrigation systems and irrigation criteria for onions are increasing onion yields and reducing environmental consequences of onion irrigation. Environmental consequences of onion production are less because water and nutrient applications are very close to the actual needs of onion.
  8. Though Puerto Rico has a tropical environment with seasonal high rainfall events, but most of cash crops are planted in the southern region of the island which is characterized by low rainfall. Drip irrigation is widely used in that region. Farmers are not using any irrigation scheduling method, so years of ground water pumping are reducing the aquifers and causing salt water inclusion from the sea. Research and extension activities area targeted to farmers at that area to teach them the importance of using an irrigation scheduling method to reduce water losses.
  9. In NY-Geneva Direct measurements of apple and grape basal ET and magnitude of water stress in the cool humid climate of NY has provided NY growers with general guidelines for irrigation. In apples it was found that normal ETo *Crop Coefficient method from arid zones overestimated irrigation requirements by as much as 100% in cool year. Installation of irrigation has greatly reduced crop losses in value due to drought and improved water use measures have saved water required.
  10. In Florida, although no impacts can be reported at this time since the study has just been initiated, the potential for substantial water savings by the strawberry industry is great if this practice is adopted.
  11. A California Almond Board sponsored grower survey has indicated that about 20% of almond growers are currently using the pressure chamber to schedule irrigation. This represents a major impact on industry practice.
  12. In New Mexico, the experimental results showed that TDR can be used to monitor diurnal soil moisture content variation in both soils. The irrigation efficiencies were very similar for furrow and drip irrigation systems. However, the results indicate that shifting from furrow irrigation to drip irrigation can lower NO3-N leaching; improve N use efficiency with lower water inputs.
  13. In New Mexico, research showed that bud break in Pecan roots is very sensitive to the soil water electrical conductivity.
  14. The 1 D model developed by New Mexico over estimated seasonal ET compared to the measured values for onions by 20% and for chile by 12%. The 2 D model over estimates seasonal ET compared to the measured values for onion by 5% and for chile by 8%. Therefore, the 2 D model is recommended for scheduling irrigation for trickle irrigated shallow rooted crops. For deep rooted crops both the 1D and 2D models give reasonable results but the 2 D model simulates the seasonal water balance better than the 1 D model. Use of the new 2 D model will improve irrigation efficiency for shallow rooted crops and decrease pollution to the ground water.
  15. In Farmington, NM, drip irrigated hybrid poplar production in northwest New Mexico had the highest mean yield of 48 kg per tree (148 Mg ha-1) compared to seven other locations in a multilocational biofuel trial in the western United States.
  16. In Farmington, NM, expanding phytoremediation work at the former site of a petroleum refinery. The project was initiated in 2010 using drip irrigation to establish hybrid poplar, local poplar, and shrubby species. This may provide a starting point for potential projects associated with the petroleum industry in our area.
  17. Farmington, NM, identified flow rates and application uniformities of several models of drip emitters, drip tubing and drip tape at water pressures lower than recommended by the manufacturers. Measured flow rates of all emitters were lower than those specified at recommended pressure but application uniformities were greater than 0.90 for three point source emitters, one line source drip tubing and one drip tape.
  18. In Farmington, NM, formulated climate and plant canopy based adjustment factors and formulae for scheduling microirrigations on drought-tolerant landscape plants and vegetable crops.