Relating soil physical properties to other soil properties and crop yields

Authors: Sainju, Upendra; LIPTZIN, DANIEL - Soil Health Institute; Jabro, Jalal "jay"

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/16/2022
Publication Date: 12/20/2022
Citation: Sainju, U.M., Liptzin, D., Jabro, J.D. 2022. Relating soil physical properties to other soil properties and crop yields. Scientific Reports. 12. Article 22025. https://doi.org/10.1038/s41598-022-26619-8.
DOI: https://doi.org/10.1038/s41598-022-26619-8

Interpretive Summary: The function of a healthy soil is influenced by numerous biological, chemical and physical soil characteristics. Soil physical properties influence water, air and nutrient movement, soil temperature, root growth, and crop yield. One critical physical property of soil is the stability of soil aggregates, which are groups of soil particles bound together by both biological and abiotic processes. Increased soil aggregation enhances water and nutrient movement, reduces soil erosion, promotes C sequestration, favors microbial activity and increases root growth. Stable soil aggregates are typically associated with healthy soils. Weak soil aggregates easily dissolve, or slake, in water and are not as beneficial as stable aggregates. Scientists at ARS, Sidney, Montana in collaboration with the Soil Health Institute evaluated six soil physical properties for their response to long-term management practices and 66 other soil properties and crop yields at two dryland farm sites in eastern Montana. They reported that slaking resistance of soil aggregates measured by a simple smart phone app was more effective at revealing the impact of management practices on soil health than the other five soil properties they evaluated. This metric was also more closely related to most other beneficial soil properties and crop yields. Slaking resistance of soil aggregates is easy to measure, rapid, and inexpensive and is a promising indicator of soil health in dryland cropping systems.

Technical Abstract: Soil physical properties can be related to other soil properties and crop yields, but their evaluations as soil health indicators relating to a broad range of soil properties and long-term crop yields need further exploration. We evaluated the long-term (14 and 36 yr) effect of cropping systems and N fertilizations on selected soil physical properties and related them to 66 soil physical, chemical, biological, and biochemical properties and mean crop yields across years at two dryland farming sites in the semiarid region of the northern Great Plains, USA. Treatments were rotations of no-tillage and conventional tillage spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), pea (Pisum sativum L.), and fallow with or without N fertilization. Soil samples collected in April 2019 were analyzed for physical, chemical, biological, and biochemical properties and mean crop yields determined. Continuous cropping enhanced average slake aggregate (ASA), wet aggregate stability index (WASI), and intact core available water capacity (IAWHC), but reduced soil bulk density (BD) compared to crop-fallow. Nitrogen fertilization reduced WASI compared to no N fertilization. The ASA, WASI, and IAWHC were associated with most soil physical, chemical, biological, and biochemical properties and clay concentration was associated with nutrient concentrations. These parameters were also better related to mean crop yields across years than other soil physical properties. Because of enhanced relationship with soil properties and crop yields and simple and inexpensive measurement, ASA can be used as a promising soil health indicator in dryland cropping systems in the semiarid regions.