Key soil properties and their relationships with crop yields as affected by soil-landscape rehabilitation

Authors: Schneider, Sharon; Sutradhar, Apurba; Duke, Sara; Lehman, R - Michael; SCHUMACHER, THOMAS - South Dakota State University; LOBB, DAVID - University Of Manitoba

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2023
Publication Date: 7/19/2023
Citation: Schneider, S.K., Sutradhar, A.K., Duke, S.E., Lehman, R.M., Schumacher, T.E., Lobb, D.A. 2023. Key soil properties and their relationships with crop yields as affected by soil-landscape rehabilitation. Agronomy Journal. 115:2404-2423. https://doi.org/10.1002/agj2.21428.
DOI: https://doi.org/10.1002/agj2.21428

Interpretive Summary: Soil movement by tillage erosion and water erosion results in spatially-dependent changes in soil properties that influence productivity. Replacing translocated topsoil (soil-landscape rehabilitation) is one method to improve the productivity of severely eroded land. The objective of this study was to investigate relationships between key soil chemical, biological, and physical factors and crop growth and grain yield in eroded and rehabilitated landforms. Soil-landscape rehabilitation was performed by moving 15-20 cm of topsoil from the lower slope to the upper slope positions of replicate plots; adjacent plots were left in their eroded condition. Crop response was monitored for six years. In the upper slope, the highest-yielding plots were the crest position to which soil was added and the lowest-yielding plots were highly convex areas with no soil added. The highest yielding plots had lower inorganic carbon and higher organic carbon, and higher available nutrients, water infiltration rates, fungal and bacterial populations, wet aggregate stability, and other measures of soil quality compared with the lowest-yielding plots. Differences in surface soil inorganic carbon explained 70% of the yield variability in the upper slope. In the lower slope, the lowest yielding plots were toeslope positions from which soil was removed, which had relatively high water content and low fungal and bacterial populations. In areas of high soil loss by erosion, differences in soil properties were more important in determining crop yields than were differences in temperature and precipitation, emphasizing the importance of improving soil properties to increase yield stability. Growers, land managers, consultants, and conservation professionals can use these results to design approaches to remediate severely eroded land to improve food production.

Technical Abstract: Tillage and water erosion induce spatially-dependent changes in soil properties that influence productivity. Replacing translocated topsoil (soil-landscape rehabilitation) is one method to improve the productivity of severely eroded land. The objective of this study was to investigate relationships between key soil chemical, biological, and physical factors and crop growth and grain yield in eroded and rehabilitated landforms. Soil-landscape rehabilitation was performed by moving 15-20 cm of topsoil from the lower slope to the upper slope positions of replicate plots; adjacent plots were left in their eroded condition. Crop response was monitored for six years. In the upper slope, the highest-yielding plots were the crest position to which soil was added and the lowest-yielding plots were highly convex areas with no soil added. The highest yielding plots had lower inorganic carbon and higher organic carbon, and higher available nutrients, water infiltration rates, fungal and bacterial populations, wet aggregate stability, and other measures of soil quality compared with the lowest-yielding plots. Differences in surface soil inorganic carbon explained 70% of the yield variability in the upper slope. In the lower slope, the lowest yielding plots were toeslope positions from which soil was removed, which had relatively high water content and low fungal and bacterial populations. In areas of high soil loss by erosion, differences in soil properties were more important in determining crop yields than were differences in temperature and precipitation, emphasizing the importance of improving soil properties to increase yield stability.