Brief Summary of Minutes of Annual Meeting

Accomplishments by WERA 202 Objectives: 1) Coordinate the standardization/documentation of crop coefficients used in irrigation scheduling. A large compilation of crop coefficient literature was collected and made available to all members of the WERA 202 and the ASCE-EWRI Crop Coefficient Task Committee via an FTP site at the University of California, Davis. UC Davis researchers completed an analysis on the conversion of crop coefficients between ETo and ETr as part of the ASCE-EWRI Task Committee on Crop Coefficients. The number of climate stations was expanded, and some stations outside of California were added. A second year of data was also tested. A publication is in preparation. Another program to estimate virtual crop ETc and to determine crop coefficients is under development. In California, the crop coefficients used in the California Irrigation Management Information System were derived mainly from FAO Irrigation and Drainage Papers 24 and 56 and from the Department of Water Resources Bulletin 113-3. A new cooperative project between UC Davis and DWR was initiated to update Kc information using a combination of eddy covariance and surface renewal methods. The USBR AgriMet network for ET information uses a set of crop coefficients originally developed by the USDA Agricultural Research Service in Kimberly, Idaho. The ET procedure uses emergence dates that are provided by local contacts, such as agricultural consultants or extension agents. Other required inputs include full cover and terminate dates. AgriMet crop coefficients are available on the internet at http://www.usbr.gov/agrimet/pn/cropcurves/About_Crop_Curves.html Bushland, Texas crop coefficients were summarized on a day after planting scale. Future work will expand the summary into the FAO-56 formats for 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. Work funded through a grant from Texas Water Development Board netted data necessary to validate the multi-year corn study at the NPRF to obtain potential adjustment data of the Kcs based on actual plant stage for multiple planting dates within the TXHPET. Adjustment data have been compiled and publication is planned with linkage to the accumulated crop heat units based on the day after planting scale in the TXHPET models. Thomas Marek, in cooperation with Dr. Terry Howell of the USDA-ARS Water Management Unit at Bushland, was 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. Initial crop establishment and growth patterns indicate more cropping time is needed to establish equilibrium soil conditions around the large lysimeter. A new reference based lysimeter (12 Mg) is currently being installed in 2008 at the research site. Work is nearing completion on the revision to ASCE Manual No. 70, which is likely to be published in 2008 or 2009. No specific work on adjusting crop coefficients was done in Florida, Kansas, North Dakota, or Washington State this year. 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. In Kansas, the ET based irrigation scheduling tool KanSched has been adopted by USDA-NRCS for the EQIP program in Kansas. Twelve sessions were held to refresh and train both NRCS personnel and producers. Educational meetings numbering 9 were held to introduce ET based irrigation scheduling and services provided by the Mobile Irrigation Lab (MIL). MIL webpage visitors numbered 1,176 and page views accounted to 3,440 so far. The online irrigation scheduling tool developed in Oregon is being evaluated through a two-year project in Washington State. It is being tried by several Washington growers and supported out of Washington State University during this time period. This has been adopted by the NRCS for the EQIP program in Washington for the evaluation period. Other more simple irrigation management tools (spreadsheet and paper-based) are under evaluation for use with Washington State. In Florida, work continues on the use of soil moisture sensor-based irrigation controllers to conserve water in landscape irrigation systems as well as drip irrigated vegetable systems. All irrigation controllers used in this work are commercially available products. Water conservation in landscape irrigation systems has been shown to range from 69 to 92% during the normally frequent rainfall conditions in Florida and ranged from 15 to 40% during dry conditions without reducing turfgrass quality. Irrigation savings on vegetables has been show to be as high as 50% without reducing yields and in some cases increasing yields. In addition, this type of irrigation control has been demonstrated to reduce leaching of soluble nutrients such as nitrate nitrogen by as much as 40 to 50%. The present work has been promising in terms of demonstrating the effectiveness and efficacy of soil moisture sensor irrigation control technology. Recent work on cooperating homes in Florida has shown soil moisture sensor controlled irrigation application as low as approximately 50% of comparison homes in the same region. Although, implementation of these controllers is being demonstrated on a limited number of cooperating homes, the technology has not been widely adopted. Thus, the water conservation potential under large scale adoption is unknown. Question such as, How much human follow-up is needed after controller installation for water conservation?, still remain. Similarly, implementation of soil moisture irrigation control at the field scale under vegetable production is also unknown. Many challenges exist when implementing soil moisture irrigation control of vegetables at the field scale including: hydraulic limitations to on-demand watering, wireless sensor communication, minimum runtime to initiate drip irrigation, to name a few. In summary, this technology needs to be demonstrated and monitored for water-conservation potential and pollution reduction potential at a large scale (i.e. watershed) when implemented by users rather than controlled implementation strictly by researchers. Research on the evaluation of evapotranspiration (ET)-based irrigation controllers for landscapes was begun and will be continued in subsequent projects. An irrigation scheduling tool was created and made available through the Florida Automated Weather Network (FAWN, http://fawn.ifas.ufl.edu) for citrus and urban irrigation scheduling. The citrus tool is being implemented with cooperating growers in south Florida. The urban irrigation scheduling tool is being communicated to extension audiences and plans include implanting this tool in an organized manner to measure landscape irrigation water conservation potential. In Florida landscape irrigation, an extension run time recommendation publication (http://edis.ifas.ufl.edu/AE220) was used to set cooperating homeowner time clocks each month. Over 30 months, cumulative irrigation savings was significantly lower (by 30%) than homes without any intervention. Initial work has occurred on demonstrating soil moisture measurement with vegetable growers. Growers report value in using the soil moisture sensor readings as a tool for irrigation management. As pointed out previously, real barriers exist in implementing fully automatic irrigation control at the farm scale; however, future work will investigate this type of control. The BIS program is used somewhat in California, but it is limited to scheduling only one field at a time. Consequently, a proposal was written to work with Oregon State University to expand their irrigation management program into California. In North Dakota, the NRCS has adopted the web-based irrigation scheduling program as well as the NDSU computerized irrigation-scheduling program to support the irrigation water management portion of their Environmental Quality Incentive Program (EQIP). This is the first year for the irrigators to use the web-based program and on June 24, 2008 there were over 60 irrigators using it to schedule irrigation on 193 fields. These numbers will increase as the irrigation season in North Dakota usually starts after July 4th. In Texas, user feedback from the use of the TXHPET website has been evaluated and incorporated through new enhancements to terminology and features proposed for integration on to the TXHPET web based system. Additional user education and technical support materials will be added as needed to promote awareness and application of the features. AgriMet provides daily estimates of crop specific ET for 70 locations in Reclamations Pacific Northwest region and 21 locations in Reclamations Great Plains region in Montana. This information is used by farmers, irrigators, irrigation districts, and irrigation consultants for irrigation scheduling in the Northwest. Both regions post current weather data and crop water use information daily on websites: PN Region: http://www.usbr.gov/pn/agrimet GP Region: http://www.usbr.gov/gp/agrimet/index.cfm Both regions provide numerous responses to data requests via email and telephone. AgriMet weather data is being used by Irrisoft, Inc. to drive their smart irrigation controller technology for commercial and residential turfgrass irrigation. Reclamations AgriMet program is working with the NRCS and Oregon State University in providing near real time ET data for an online irrigation scheduling system known as OISO  Oregon Irrigation Scheduling Online. This effort is currently being expanded to the entire Northwest. Several rural agricultural newspapers publish AgriMet crop water use data during the growing season. Crop water use data is further disseminated by local contacts and working relationships with County Extension Agents, NRCS technical specialists, Soil and Water Conservation District specialists, and agricultural consultants. Bonneville Power Administration uses AgriMet ET data as a baseline for incentive payments to agricultural irrigation customers for practicing 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. a) Development of Quality Control procedures for weather data used for irrigation scheduling. 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. Quality control of weather data collected by the North Dakota Agricultural Weather Network (NDAWN) is performed first at the High Plains Climate Center in Nebraska and then is screened by NDAWN personnel. Quality control of weather data for reference ET estimation in California is managed by the California Department of Water Resources in the CIMIS program. In Florida, quality control is managed by the FAWN program. b) Development of interpolation programs to fill in missing data from climate networks. Irrigation scheduling programs will not run with any missing data. AgriMet uses meteorologically sound manual estimation procedures to completely fill in missing data. In California, the SIMETAW program for estimating irrigation water demand is being upgraded to better account for ET and rainfall variations. They are using PRISM to determine monthly temperature and precipitation data and then we use long term climate station data to estimate daily variation. From these data, a calibrated Hargreaves Samani equation is used to estimate the Penman Monteith ETo rates. This is used in conjunction with a water balance procedure to estimate effective rainfall and ET of applied water.