|Heng, Lee - FAO|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: February 6, 2007
Publication Date: February 1, 2008
Citation: 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. Interpretive Summary: Soil water measurements are important for agricultural research and water management. Research was conducted in cooperation with United Nations Food and Agriculture Organization (FAO) and the International Atomic Energy Agency (IAEA) in Texas, California and Austria to compare and quantify the performance of many soil water sensing methods. This chapter presents equipment, theory, methods and field practices for the use of tensiometers to measure the soil water matric potential, which is the energy with which water is held in the soil pores. Matric potential is a useful property of soil water because it represents the force against which plants roots must work to absorb water from the soil.
Technical Abstract: An expert group from five nations and three continents did comparative trials of soil water sensing methods under laboratory and field conditions at the behest of the joint division of the International Atomic Energy Agency and FAO, resulting in a nine-chapter guide to field estimation of soil water content. Chapter 8 presents equipment, theory, methods and field practices for the use of tensiometers to measure the soil water potential, which is the energy with which water is held in the soil. Potential energy is a useful property of soil water because it represents the force against which plants must work to take up water, which is essential for plant growth and crop yield. The tensiometer is one of the oldest and most widely used instruments for irrigation scheduling around the world. Problems and solutions are discussed, as are advantages and disadvantages of the method.