Brief Summary of Minutes of Annual Meeting

Objectives: 1) Coordinate the standardization/documentation of crop coefficients used in irrigation scheduling. " Colorado State University with funding from the Colorado Water Conservation Board is in the process of installing a large weighting lysimeter (3m x 3m x 2.5 m) at the Colorado Agricultural Experiment Station research center at Rocky Ford, Colorado (Arkansas River Basin). " CoAgMet is in the process of changing over from Kimberly-Penman to ASCE standardized PM for the reference equation. " CSU has been working on developing remote sensing of ET using an energy balance model RESET (Remote Sensing of ET) following a similar methodology as SEBAL and METRIC. " Texas is cooperating with Rick Allen (CA) 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. 70and is likely to be published in 2007. " Bushland (TX) crop coefficients were summarized on a day after planting scale. Future work will expand the summary into the FAO-56 formats for both ASCE/EWRI reference ET for GDD and ground cover scales. " Crop coefficients derived from the large weighing lysimeters at Bushland over time have been estimated per growth stage for the multiple planting dates within the TXHPET models. A multiple crop (corn, grain sorghum and soybeans), long season variety, replicated, study is underway at the NPRF to gather adjustment data of the Kcs based on plant stage for multi-planted dates in the TXHPET. The adjustment is planned for linkage to accumulated crop heat units based on the day after planting scale. " Thomas Marek, in cooperation with Dr. Terry Howell of the ARS Water Management Unit at Bushland has been involved in the design, construction, installation and instrumentation of a large weighing lysimeter for crop coefficient determination in the Arkansas River Valley region of Colorado. " The automated irrigation scheduling for center pivot irrigation project involves the concept that combines proven monitoring and control hardware (developed by SDSU and AgSense) with a software package that calculates ET and soil water balances to manage the center pivot water applications with minimal operator intervention during the irrigation season. " An irrigation scheduling model was developed to simulate operation and water management of the center pivot machine. " SDSU has provided crop water use information (ET) for three years on their Climate Web Page. The project was initially implemented for three automatic weather stations in western South Dakota and was funded by the Bureau of Reclamation. Subsequently, crop water use has been available in query mode for 12 automatic weather stations. Eight sites will be added in 2006. " AgriMet uses a set of crop coefficients originally developed by the USDA Agricultural Research Service in Kimberly, Idaho. " AgriMet is researching the use of degree day methods to predict the break dormancy dates for perennial crops (alfalfa, pasture, hay, and lawn). Hopefully, these methods will be implemented in spring of 2007. " The US Bureau of Reclamation operates a network of 72 automated agricultural weather stations in the Pacific Northwest region, and 21 stations in the Great Plains region in Eastern Montana producing crop water use charts that are crop specific and station specific. This requires close coordination with local crop contacts (extension agents, crop consultants, etc.) in order to tie local crop development conditions to crop coefficient curves. " New Mexico introduced 2 low-cost soil monitoring instruments to a group of pecan producers, provide instruction on the use of internet-based irrigation scheduling resources, and provide assistance in utilizing these tools to improve their irrigation scheduling and possibly yield. Three out of five growers indicated they used either the granular matrix sensors (GMS) or tensiometer to schedule irrigations, but compared to the climate-based irrigation scheduling model, all growers tended to irrigate later than the models recommendation. " Graphical analysis of time-series soil moisture content measured with the GMS showed a decrease in the rate of soil moisture extraction coincident with the models recommended irrigation dates. These inflection points indicated the depletion of readily available soil moisture in the root zone. The findings support the accuracy of the climate-based model and suggest that the model may be used to calibrate the sensors. " Adjustment of alfalfa reference crop based local crop coefficients have been made by Kansas State University for those who wish to use ET estimates made using Penman-Monteith equation for grass reference crop. " Work is in progress to improve and update existing irrigation scheduling software and soon KanSched2 will be released. 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. " Colorado has data from two irrigation management surveys, which show ET-based irrigation scheduling has low (<15%) adoption in most areas. It is highest in the San Luis Valley. " The AgriPartner program of Texas Cooperative Extension [Mr. Leon New, Mr. O.R. (Reggie) 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 2005. The total number of field demonstrations was 43 and represented a slight reduction in overall number as compared to the previous year due again to reduced funding for the program. The total program evaluations and acreages conducted in 2005 were as follow: Crop # Demonstrations Acreage # Counties " corn 4 300 3 " cotton 17 1400 9 " forage/silage 2 121 2 " peanut 6 547 2 " sorghum 3 340 2 " wheat (2004) 8 727 4 " soybean 3 369 3 Total 43 3,806 25 " Part-time AgriPartner employees 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. There were 31 producers that participated in the AgriPartner demonstrations. 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. " The AgriMet program currently uses a custom graphical program to perform a daily review of all weather parameters used of ET computation. The AgriMet is currently developing a web connected excel-based spreadsheet approach that will improve this procedure. " Extension education meetings in Kansas counties for hands on training for using ET based irrigation scheduling tool KanSched. Annual Central Plains Irrigation Conference & Exposition has been a significant venue for this type of educational activities as well. Presentation also made at Irrigation Association (IA) meeting. " Kansas has developed effective documentation of irrigation scheduling information available through the web. www.oznet.ksu.edu/mil and www.oznet.ksu.edu/wdl " Annual Central Plains Irrigation Conference & Exposition has been a significant venue for this type of educational activity to irrigation industry groups. " The ABE Department in South Dakota implemented an email newsletter to extension personnel. Updates and articles have presented information on irrigation management and water conservation.