Conservation tillage and soil water

Authors: Baumhardt, Roland - Louis; Lascano, Robert

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 10/7/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: Global climate has been predicted to become both warmer and drier which, in turn, impacts soil hydrology depending upon soil management. Conservation tillage and, later, reduced- or no-tillage were developed as a means to retain residues at the soil surface for controlling wind or water driven soil erosion that had grown to catastrophic proportions during the 1930s dust bowl. Various conventional tillage implements are related to residues retained and the soil tillage intensity rating and contrasted with conservation tillage practices regarding water conservation by ARS scientists at Bushland and Lubbock, Texas. Tillage effects on water sources like surface inflow and losses to surface runoff are combined with the discussion of the infiltration and evaporation hydrologic processes. This information may advance optimum use of conservation tillage to adapt food production for a changing climate.

Technical Abstract: In the semiarid U.S. Great Plains, reduced or no conservation tillage has been primarily directed towards the control of soil erosion either by wind or water in contrast to conventional tillage practices that bury some fraction or all of the crop residue. The type, depth and degree of soil disturbance differs among the various conventional tillage tools compared to conservation tillage that may vary in the geometry or the amount of residue retained. An additional advantage of conservation tillage is to increase soil water storage during fallow, subsequently increasing yields of crops like wheat (Triticum aestivum L.) and sorghum (Sorghum bicolor, L.). In general, the effects of surface residue on field hydrology are to increase infiltration of precipitation by intercepting rain and to reduce evaporative losses of water by modifying the energy balance at the soil surface. In this chapter, we initially describe and discuss conservation and conventional tillage practices, and equipment as well as the field water balance governing soil water storage, which includes water inputs and losses. Processes and mechanisms of conservation or conventional tillage and management practices are sufficiently detailed to provide inferences that may support their optimization during a gradually changing climate.