Drainage evaluation under subsurface drip irrigated corn.

摘要

The Ogallala aquifer is the major water supply for irrigation in the High Plains. Water withdrawals from the Ogallala aquifer, especially during drought periods, have caused a net loss of groundwater and declining water table levels. Subsurface drip irrigation systems have been introduced in an attempt to use water more efficiently. Installation costs for subsurface drip irrigation systems are relatively high. Optimizing the spacing between driplines, and minimizing the amount of irrigation water needed for good crop yields, are important. Drainage of water plays a vital role in making decisions on spacing between driplines and on the amount of irrigation water. Field studies were conducted during the summers of 1990 and 1991 near Colby and Holcomb, KS. The soil near Colby is Keith silt loam (fine-silty, mixed, mesic Aridic Argiustoll). The soil near Holcomb is Richfield silt loam (fine, montmorillonitic, mesic Aridic Argiustoll). The objective of this study was to develop the relationships between drainage of water at the 1.52 m soil depth and dripline spacing, and between drainage of water at the 1.52 m soil depth and irrigation application amount. We used subsurface drip irrigation systems with corn (Zea mays L.). Soil water flux (drainage) was calculated by using Darcy's equation. A relationship between drainage and spacing between driplines was obtained from a dripline spacing study near Colby. The relationship between growing season drainage at the 1.52 m soil depth and dripline spacing is