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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 5/1/2006 Publication Date: 6/1/2007 Citation: Evett, S.R. 2007. Chapter 2: Soil water and monitoring technology. In: Lascano, R.J., Sojka, R.E., editors. Irrigation of Agricultural Crops, 2nd edition. American Society of Agronomy Monograph No. 30. Madison, WI:American Society of Agronomy. p. 25-84. Interpretive Summary: Soil water content and the ease with which plants can get water from the soil are properties that are often measured in order to guide management of irrigation and drainage. Also, these are often necessary measurements in irrigation and drainage research. The soil water status affects crop water use and the ability of crops to increase yield by uptake of nutrients from the soil and carbon dioxide from the atmosphere. Because soil water status is reflected in crop water status, there are many links between soil water status and crop response, such as rapidity of growth, wilting due to lack of water, and fruit quality and size. Because soil water status is modified by crop water uptake, the dynamics of soil water properties are affected by the dynamics of weather, both daily and over longer periods, and by crop growth as modified by soil fertility, pests, and diseases. Thus, observation of soil water dynamics may be useful for crop management. The objective of irrigation and drainage management is to control soil water status. However, the goal for crop management may be to obtain maximum crop yield, maximum water use efficiency, soil dry enough for harvest operations, or a combination of these with other goals. This chapter provides state-of-the-art information on measurement principles and technologies for soil water. Technical Abstract: Soil water content and the energy potential of soil water are properties that are often measured in order to guide management of irrigation and drainage, and that are frequently necessary measurements in irrigation and drainage research. The soil water status affects the transpiration stream of crops and their ability to uptake nutrients from the soil and CO2 from the atmosphere for yield formation. Because soil water status is reflected in crop water status, there are many links between soil water status and crop physiological response, including leaf turgor and orientation, growth through cell expansion and division, rooting, stomatal size, chemical (hormonal) processes, flowering, fruiting, senescence, canopy temperature, etc. Because soil water status is modified by crop water uptake, the dynamics of soil water properties are affected by the dynamics of weather, both diurnally and over longer periods, and by crop growth and senescence as modified by soil fertility, pests, and diseases. Thus, observation of soil water dynamics may be useful for crop management. The objective of irrigation and drainage management is to control soil water status; but the goal for crop management may be to obtain maximum crop yield, maximum water use efficiency, soil dry enough for harvest operations, or a combination of these with other goals. This chapter provides state-of-the-art information on measurement principles and technologies for soil water. |
