Effect of Straw Mulch Rates on Soil Water Storage during Summer Fallow in the Great Plains

Abstract

AbstractNet gains in soil water storage during fallow due to increased quantities of wheat (Triticum aestivum L.) straw mulch varied from 1.0 to 4.3 cm at Sidney, Mont., from 2.1 to 4.1 cm at Akron, Colo., and from 1.3 to 3.3 cm at North Platte, Nebr. These gains were made primarily during the spring months of the 14‐month fallow season. More than 70% of the net gains in soil water under heavier amounts of mulch was found below the surface 61 cm of the soil profile at all experimental locations, thereby minimizing potential evaporation losses. Storage of water tended to increase with the delayed date of straw burial in Nebraska. Additional soil water was conserved at Akron, Colo. during the first fall by subtillage of wheat stubble at harvest when compared with spring subtillage; however, by the end of the fallow there was no significant difference between treatments. Fallow efficiencies averaged 22, 30, and 32% for all treatments at the Montana, Colorado, and Nebraska locations respectively.