Developing reservoir tillage technology for semi‐arid environments

Abstract

AbstractArable farming on suitable land in semi‐arid environments is hampered by low and erratic rainfall and droughts. To use this land effectively, techniques, such as water harvesting may improve soil water storage and increase agricultural productivity. Laboratory experiments were conducted to assess two reservoir tillage methods under different slopes, rainfall intensities and soil densities. A commercial trailed tillage tool (Aqueel) was used to form discrete soil depressions by compression of the soil and a soil scooping device with similar dimensions was used to make depressions in shear by lifting the soil out. The results show that, for the sandy loam used in this study, reservoir tillage is an effective method of harvesting water under high‐intensity rainfall of short duration common in semi‐arid areas. It reduced surface run‐off by 95% on 10° slopes when depressions were staggered and positioned with their long axis across slope. However, high initial soil bulk densities lead to a significant reduction in the volume of the depressions formed in compression and to internal compaction. Increasing vertical load on the Aqueel resulted in an increase in depression volume without an increase in internal compaction but at high bulk densities the depression volumes remained small and high implement load damaged the depression function and stability. This suggests a need for a pre‐loosening tillage operation for compacted soils and the need to design new implements to form depressions in shear.