Crop residue management and soil water

Authors: RUIS, SABRINA - University Of Nebraska; Johnson, Jane; BLANCO-CANQUI, HUMBERTO - University Of Nebraska

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 5/27/2021
Publication Date: 7/1/2022
Citation: Ruis, S., Johnson, J.M., Blanco-Canqui, H. 2022. Crop residue management and soil water. In: Blanco, H., Kumar, S., Anderson, A., editors. Soil Hydrology in a Changing Climate. Clayton South, VIC, Australia: CSIRO Publishing. p. 107-131.

Interpretive Summary: Baling, grazing, and burning remove crop residue from the field instead of leaving them on the soil surface or tilling them into the soil. What happens to how water enters and moves into the soil after removing crop residue needs to be discussed and reviewed. Available research data indicated baling more than half the crop residue from high yielding fields reduced how much water entered the soil and caused undesirable changes in how water moved in the soil and even how much water the soil could provide to plants. The changes observed were due in part because removing too much crop residue caused the soil to lose organic matter, and other soil properties were degraded. So long as the fields were not over-stocked, and only a small amount of the residue was removed so the field had plenty of soil coverage it caused little change in water related soil-properties. Burning is a very aggressive form of residue removal, causing problems similar to over harvesting by other methods. Leaving soil exposed meant less water from rain, snow or irrigation entered the soil and more water ran-off or evaporated. Limiting the amount of residue removed by baling, grazing or burning needs to be managed to protect the soil and the environment.

Technical Abstract: Crop residue management strategies such as baling, grazing, and burning can alter soil surface cover leading to reduced soil C and increased risks of water and wind erosion. As a result, these strategies may also alter soil hydrological characteristics. The objective of this chapter was to discuss the impacts of crop residue management strategies including baling, grazing, and burning on hydraulic properties and soil hydrology. Available research data indicate that crop residue baling at rates that leave <50% soil coverage can reduce water infiltration, saturated and unsaturated hydraulic conductivity, and water retention (i.e. plant available water). These adverse effects on soil hydraulic properties can be explained partly by the loss of soil C and degradation of soil structural properties. Crop residue baling increases runoff and sediment loss. However, residue grazing typically has minimal impacts on soil hydraulic properties because it normally removes <30% of residues compared to residue baling. Similar to residue baling, residue burning can have adverse effects on soil hydraulic properties. It can reduce water infiltration. High rates of residue removal can also reduce capture of rain, irrigation, and snow, and increase evaporation, adversely affecting water storage in the soil profile. Establishing threshold levels of residue removal can be key to maintain soil hydraulic properties and develop resilient agroecosystems.