Water infiltration into a glacial till soil following subsoiling and secondary tillage

Water limits crop production in the semiarid northern Great Plains of the United States. Summer fallow is commonly practiced to store water in the soil for use by a later crop (Haas, el al., 1974). However, high evaporation rates makes summer fallowing inefficient in storing water (Tanka, 1985; Tanka and Aase, 1987). Additionally, the fallow-wheat (Triticum aestivum L.) crop sequence has been implicated as the cause of serious declines in soil organic carbon (Rasmussen and Parton, 1994). A recent report by Aase and Pikul (1995) showed that annually grown spring wheat was an acceptable alternative to the traditional fallow-wheat crop sequence in eastern Montana, USA. To successfully grow a crop every year, however, it is essential to conserve as much precipitation as possible between harvest and seeding. Specialized tillage is thought to improve water infiltration and soil water storage. Pikul et al. (1996) have shown that soil ripping on the contour may improve water infiltration into frozen soil and possibly increase soil water storage. Objectives were to 1) determine the effect of soil ripping on water infiltration and 2) evaluate the durability of tillage induced soil structure following repeated wetting and drying cycles