This bulletin embodies a part of the data secured in the irrigation investigations of this Station. It aims to contribute something to our knowledge of the movement of water in irrigated soils . The science of irrigation can not well be built until the laws involved in the mutual relationships of waters, soils and crops are understood with fair accuracy. Much has been done by numerous investigators, during the last fifty years, to give a clearer comprehension of the movement of soil moisture; but the field experiments have dealt largely with saturated soils, and the laboratory experiments have seldom taken account of the special conditions under which irrigation is practiced. The experiments here reported were all conducted under field conditions and on irrigated soils. The results were obtained in the field; the unsaturated condition characteristic of irrigated fields prevailed throughout; and the water movements were followed to a much greater depth than in the majority of reported investigations--these particulars characterize these investigations.
Widtsoe, J. A. and McLaughlin, W. W., "Bulletin No. 115 - The Movement of Water in Irrigated Soils" (1912). UAES Bulletins. Paper 66.