Brief Summary of Minutes of Annual Meeting

Accomplishments: Objectives: 1) Coordinate the standardization/documentation of crop coefficients used in irrigation scheduling. Terry Howell (TX) continues cooperating with Rick Allen (ID) on modifying the FAO-56 equations with the ASCE/EWRI standardized hourly equation for a short reference crop (grass). Work is nearing completion on the revision to ASCE Manual No. 70 and is targeted to be published in 2007. Future work will expand the summary into the FAO-56 formats for both ASCE/EWRI reference ET for GDD and ground cover scales. Forage sorghum ET assessment on the lysimeters at Bushland is continuing in 2007. Crop coefficients derived from the large weighing lysimeters over time have been estimated per average growth stage for the multiple planting dates within the TXHPET models. The multiple, replicated, long season crop varieties study at the North Plains Research Field was completed in 2006 to gather adjustment data of the Kcs based on plant stage for multi-planted dates in the TXHPET. TXHPET growth stage model adjustment is planned in 2007-08 for linkage to accumulated crop heat units based on the day after planting scale. Thomas Marek, in cooperation with Dr. Terry Howell, was involved in the design, construction, installation and instrumentation of a large weighing lysimeter (similar to the unit at Bushland) for crop coefficient determination in the Arkansas River Valley region of Colorado. A scientific operations meeting was held at Rocky Ford, CO to assist personnel in operating the units. Installation and instrumentation of the large, monolithic lysimeter unit (3m x 3m x 2.5 m depth) is complete and is being planted and furrow irrigated to initiate equilibrium soil conditions around the lysimeter. Preliminary calibration results indicate a very high sensitivity level of the unit. Similarly, 2 additional lysimeters have been installed by Thomas Marek at Uvalde with lighter soils for regional vegetable ET crop coefficient determination, bringing the total to 6 fields and 1 grass reference unit. The work is being conducted cooperatively between Amarillo, Bushland and Uvalde. The automated irrigation scheduling system for center pivots developed by SDSU and AgSense is ready for field trials and involves the concept that combines proven monitoring and control hardware with a software package. The system calculates ET and soil water balances to manage the center pivot water applications with minimal operator intervention during the irrigation season. SDSU currently has 2 cooperators that are willing to field trial the system. SDSU has computed crop water use information (ET) for four years on the SDSU Climate Web Page. The project was initially implemented for three automatic weather stations in western South Dakota and is now available in a query mode for 12 automatic weather stations. Snyder and colleagues (CA) have developed a new computer application program (DETAW) to (1) estimate reference evapotranspiration in the Sacramento-San Joaquin River Delta from 82 years of climate data, (2) correct for microclimate changes across the Delta, (3) apply crop coefficients to estimate evapotranspiration for 16 surface types, (4) use soil and crop characteristics to estimate yield thresholds and to determine management allowable depletions for irrigation schedule modeling, (5) model irrigation events, effective rainfall, and ground water seepage contributions based on water additions and losses, (6) determine evapotranspiration of applied water (ETAW), and convert the results to acre-feet of water used in the Delta uplands and lowlands. Efforts are expanding to determine crop coefficients using the surface renewal method. The California Department of Water Resources (DWR) has funded the purchase of 10 surface renewal stations and 10 sonic anemometer stations for calibration purposes. The University is working with the DWR regional staff people to train personnel on how to collect ET data for upgrading crop coefficient values. Snyder and staff have continued to work on the conversion of crop coefficients between ETo and ETr as part of the ASCE-EWRI Task Committee on Crop Coefficients. A simple method to convert was developed; however, additional work on improving the conversions will be presented at the Task Committee meeting in October 2007 at the USCID Conference in Sacramento, CA. Terry Howell and staff have worked on comparing the TXHPET data with results to be presented accordingly at the USCID meeting as well. CA personnel have worked with the NWS to add ETo to the NWS forecast products. The Sacramento NWS Office has developed software to add a daily ETo rate forecast to their prototype weather forecast page and they have developed a daily forecast ETo map. Scherer reported that since 1995 the NDSU Extension Service has provided accurate daily crop ET values to irrigators for the 10 major irrigated crops in North Dakota. These estimates are calculated using the weather data from the automated weather stations of the North Dakota Agricultural Weather Network (NDAWN) website: http://ndawn.ndsu.nodak.edu/index.html. The user can view the daily water use of each crop as color coded maps or as numerical tables. Scherer (NDSU) indicated that crop water use maps and numerical tables on the NDAWN system were used extensively for irrigation scheduling. In June, July, August and September of 2006, there were around 5,000 successful requests for crop water use information. July had the most requests with the busiest week days being Monday and Thursday. During the day, 9 am to noon was the busiest time period. Many crop consultants working with irrigators access the Web site at least twice per week and increase the impact of the irrigation water management information by providing a multiplier effect. AgriMet continues to use crop coefficients derived by the ARS scientists at Kimberly, Idaho and computation of their ET procedure uses emergence dates that are provided by local contacts, producing crop water use charts that are crop specific and station specific. The 2007BRC network operated over 70 automated agricultural weather stations in the Pacific Northwest region, and 21 stations in the Great Plains region in Eastern Montana. 2) Evaluation of the effectiveness of irrigation scheduling tools. This will include any information collected to determine the types of irrigation scheduling tools used by growers. California personnel documented a state survey of irrigation system use in 2002 that has been accepted for publication in the Journal of irrigation and Drainage, ASCE. An observation of growers using pressurized irrigation systems was that they were considerably more likely to use any irrigation scheduling method; this being important for possible adoption toward future use of ET-based or other methods of scheduling. NDSU(Scherer) indicated that the NRCS has adopted the NDSU computerized irrigation-scheduling program to support the irrigation water management portion of their Environmental Quality Incentive Program (EQIP). The program provides documentation showing irrigation management decisions made by the cooperator that the NRCS need to evaluate the impact of their water conservation programs. Since the inception of this program in 2003, over 200 copies of the program have been distributed to EQIP participants. Copies were also provided to many county NRCS offices and the state irrigation engineer The AgriPartner program of Texas Cooperative Extension [Mr. Leon New, Mr. O.R. Jones (Coordinator), Dr. Brent Bean, Dr. Carl Patrick and Mr. Don Dusek] continued operations of on-farm irrigation and dryland demonstrations where the North Plains ET (NPET) network (part of the Texas High Plains ET network) models and irrigation scheduling data were again validated and utilized with area producers in 2006. The total number of field demonstrations was 44. In total, there were 7 program crop evaluations in 25 counties with 5,625 acreages monitored in 2006. There were 34 producers that participated in the AgriPartner demonstrations. Thomas Marek at the North Plains Research Field conducted an ancillary research versus field monitored study in 2006 and resulted in the monitoring of 1,780 acres of crops, principally corn with 12 growers participating. Percentage of full ET applied by growers ranged from 55 to 95.3 %. Both efforts acquired data on the various commercial fields that tracked applied irrigation water (pivot, subsurface drip or furrow irrigation), rainfall, soil water use, yields, and crop phenology. Overall, the NPET crop growth models performed well again in 2006. Ted Sammons (NM) illustrated the new irrigation scheduling estimator that the Pecanigator software tool utilizes. This tool has been unveiled to farmers in the NM region for irrigation of pecans through a flood method. The objective was to promote a simple change into the concept of irrigation scheduling. 3) Coordinate with the irrigation industry group (The Irrigation Association) on updating their database on existing agricultural weather networks in the US, their websites, weather data provided (present and historical) and irrigation scheduling information. CA personnel, regarding the Sacramento- San Joaquin River Delta (DETAW) project, used data from recent decades to develop a relationship between the Penman-Monteith (PM) ETo at several stations versus the Hargreaves-Samani (HS) ETo from one station (Lodi, CA). The results were used to identify isolines of correction factors to convert from HS ETo to PM ETo. Since temperature data were available from 1921 to the present, personnel were able to estimate the spatial distribution of PM ETo using 82 years of temperature data from Lodi. In addition, estimation of the daily spatial distribution of rainfall across the Delta was computed to determine weighting factors to estimate rainfall at any point within the Delta. Scherer indicated that NDAWN quality control and missing data and correction analysis is is performed initially at the High Plains Climate Center in Nebraska and then by NDAWN personnel. Missing data are interpolated from the five surrounding weather stations of NDAWN with NDAWN personnel then performing correction of the mechanical or electronic problem. AgriMet has developed a set of manual quality control procedures, both text-based and graphical, that easily identify any errors in the meteorological data used in ET computation. AgriMet uses meteorologically sound manual estimation procedures to completely fill in missing data. KSU illustrated a new web front end R&E site created with links to past meteorological data sets. Data QC routines are implemented and patterned after much of the routines of the Oklahoma Mesonet plus additional parameter limits are based on range, step and persistence tests.