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United States Department of Agriculture

Agricultural Research Service

Research Project: IRRIGATION MANAGEMENT AND AUTOMATION FOR INCREASED WATER USE EFFICIENCY
2008 Annual Report


1a.Objectives (from AD-416)
Determine methods for improved quantification of evapotranspiration (ET) and crop coefficients under all constraints in order to improve irrigation scheduling and water use efficiency. Develop remote sensing technologies and tools designed for improved prediction of crop water use and water stress at field and watershed spatial scales. Develop, test, and implement feedback systems for spatially and temporally variable irrigation application of water and nutrients, and develop, test and implement improved sensors for soil water content and plant stress. Develop and validate remote sensing technologies and procedures to enhance spatially and temporally variable crop water status feedback systems for use in variable rate irrigation systems. Quantify and improve crop water use efficiency in dryland/irrigated cropping systems in relation to tillage, irrigation, and crop management practices.


1b.Approach (from AD-416)
Research approaches include determinations of crop water use by soil water balance techniques (weighing lysimeters and neutron scattering methods) in practically all experiments, which include variations in irrigation method (subsurface drip at several depths and spacings, sprinkler, and low energy precision application or LEPA), irrigation amount (full and two to three levels of deficit), tillage (no-tillage, conventional, strip till, etc.), and/or crop and crop rotation, including rotation between irrigated and dryland cropping. Automatic irrigation systems based on sensing of crop status are designed/engineered and tested for ability to control crop water use efficiency and yield, thus reducing management expense (time and effort) while allowing management to control irrigation for best profitability and optimum water use. Key in this effort is evaluation and design of new crop and soil water status sensors. Remote sensing approaches to water use prediction are expected to improve energy balance modeling methods to make them useful for managers at farm, irrigation project, and watershed scales, and for policy makers.


3.Progress Report
Irrigation automation research was continued, partly under subordinate project 6209-13000-012-03R, which entailed cooperative research with an Israeli team to develop relationships between crop water stress & leaf reflectance in several colors, including the invisible thermal infrared. A strong relationship was found between a thermal water stress index & an index based on measurements of three colors in the visible range, which are easier & less expensive to measure than the thermal index. The subordinate project was completed & terminated.

Irrigated & dryland cotton water use was studied using four large weighing lysimeters & adjacent automated center pivots. These studies were integrated into a coordinated research project named Bushland Evapotranspiration & Agricultural Remote Sensing Experiment 2008 (BEAREX2008), including scientists from ARS laboratories at Bushland, TX; Beltsville, MD; Ames, IA; & Maricopa, AZ; and scientists from the University of Alabama, University of Oklahoma, University of Idaho, & Utah State University. The project aims to develop remote sensing technologies & tools designed for improved prediction of crop water use & water stress at field & watershed spatial scales. A net radiation model was improved for row crops based on radiation measurements on corn, sorghum, & cotton. The radiation model is being tested with data from the 2007 & 2008 growing seasons. Net radiation to the soil & canopy are major components of models for crop water use & stress detection. Corn germination problems with subsurface drip irrigation were studied in 2007 & 2008. Comparisons of irrigation application systems [sprinkler spray, subsurface drip, & low energy precision application (LEPA)], & their effect on seed bed soil water content & temperature during germination continued with cotton as the test crop, showing some differences in seed bed temperature & water content due to different application methods (drip versus spray irrigation for example). This has implications for early season growth of cotton, which is sensitive to soil temperature. The final season for these measurements is underway in 2008.

Research on water use & productivity of sunflower is underway in 2008. Sunflowers are grown in lysimeters containing four soil types using four irrigation treatments (25, 50, 75, 100% replacement of ET) in a rain shelter facility. For biomass accumulation (crop height), there has been a significant interaction between soil type & irrigation level. Biomass accumulation has been reduced with decreasing irrigation level for the sunflower grown in clay & silt loam soils, but has been unaffected by decreased irrigation for the crops in sandy loam & fine sand.

Under the subordinate project number 6209-13000-012-04S, the recently developed Texas High Plains Evapotranspiration Network (TXHPET) system & automated listserv continued delivering electronically advanced, updated, standardized, precision irrigation scheduling data & detailed meteorological data to irrigated producers daily in FY08. Data requests from 20 federal & state agency research & extension projects were met. (NP211, Problem Areas 2.1, 2.2, 2.4 and 2.5, and 5.5 and 5.6)


4.Accomplishments
1. NEW GUIDE TO SOIL WATER CONTENT SENSING FOR IMPROVED WATER MANAGEMENT: Accurate knowledge of soil water content is key to efficient water management in both irrigated and dryland agriculture, but existing soil water sensors do not work well under all conditions. Scientists in the Soil and Water Management Research Unit, Bushland, Texas, led and collaborated with an international team convened by the International Atomic Energy Agency to assess the accuracy and utility of the major types of sensors and to produce a guide to sensors, including which sensors are useful under which soil conditions. A nine-chapter book, 'Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology,' and associated journal articles were published and made available on the Internet and in hard copy for use by irrigation and natural resource managers, scientists and engineers. New knowledge about sensor problems in common soil conditions was generated, is being used to develop improved sensors, and was transmitted to the Irrigation Association to guide sensor evaluation in the Smart Water Application Technologies (SWAT) program approved by EPA. Sensor manufacturers have requested assistance in solving problems with the sensors and a research team was assembled to develop improved sensors. (NP211, Problem Area 2.4)


6.Technology Transfer

Number of Web Sites Managed2
Number of Non-Peer Reviewed Presentations and Proceedings3
Number of Newspaper Articles and Other Presentations for Non-Science Audiences2

Review Publications
Balota, M., Payne, W.A., Evett, S.R., Lazar, M.D. 2007. Canopy temperature depression sampling to assess grain yield and genotypic differentiation in winter wheat. Crop Science. 47:1518-1529.

Farahani, H.J., Howell, T.A., Shuttleworth, W.J., Bausch, W.C. 2007. Evapotranspiration: Progress in measurement and modeling in agriculture. Transactions of the ASABE. 50(5):1627-1638.

Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L. 2008. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. 131 p.

Evett, S.R. 2008. Gravimetric and volumetric direct measurement of soil water content. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 23-37.

Evett, S.R. 2008. Neutron moisture meters. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 39-54.

Evett, S.R. 2008. Conventional time domain reflectometry systems. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 55-72.

Evett, S.R. 2008. Capacitance sensors for use in access tubes. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 73-90.

Heng, L.K., Evett, S.R. 2008. Tensiometers. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 113-121.

Hignett, C., Evett, S.R. 2008. Direct and surrogate measures of soil water content. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 1-22.

Evett, S.R., Hignett, C., Heng, L. 2008. Electrical resistance sensors for soil water tension estimates. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 123-129.

Laurent, J., Evett, S.R. 2008. TrimeĀ® FM3 moisture meter and T3 access tube probe. In: Evett, S.R., Heng, L.K., Moutonnet, P., Nguyen, M.L., editors. Field Estimation of Soil Water Content: A Practical Guide to Methods, Instrumentation, and Sensor Technology. IAEA-TCS-30. International Atomic Energy Agency, Vienna, Austria. ISSN 1018-5518. p. 91-100.

Peters, R.T., Evett, S.R. 2008. Automation of a center pivot using the temperature-time-threshold method of irriation scheduling. Journal of Irrigation and Drainage Engineering. 134(3):286-291.

Mazahrih, N., Nedal, K., Evett, S.R., Ayars, J.E., Trout, T.J. 2008. Field calibration accuracy and utility for four down-hole water content sensors. Vadose Zone Journal. 7:992-1000.

Last Modified: 11/27/2014
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