Location: Agricultural Systems ResearchTitle: Soil cone index and bulk density of a sandy loam under no-till and conventional tillage in a corn-soybean rotation
Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2020
Publication Date: 2/1/2021
Citation: Jabro, J.D., Stevens, W.B., Iversen, W.M., Sainju, U.M., Allen, B.L. 2021. Soil cone index and bulk density of a sandy loam under no-till and conventional tillage in a corn-soybean rotation. Soil & Tillage Research. 206:Article e104842. https://doi.org/10.1016/j.still.2020.104842.
Interpretive Summary: Tillage is one of the most prominent agricultural practices that can directly alters soil physical properties and affects crop yield and quality. Selection of tillage type is important to sustain soil quality and health required for successful growth of agricultural crops. Soil compaction is the reduction in soil volume due to driving heavy farm equipment on wet soils that are used for agricultural production. Compaction caused by field operations and wheel traffic from heavy farm machinery is an acknowledged problem worldwide and may happen during tillage, planting, spraying, harvesting, and other farming activities. Based on the results of this study, no-till tended to increase soil penetration resistance and bulk density in the top 0 - 30 cm layer compared with intense tillage practices under both corn and soybean in corn-soybean rotation. Lower soil penetration resistance and bulk density values in intense tillage was associated with soil disturbance and overturn caused by deep tillage as well as incorporation of crop residues into the soil surface layer. Both soil penetration resistance and bulk density as indicators of soil compaction were adversely affected by no-till system. Therefore, no-till farming practices should be cautiously adopted in sandy loam soils to prevent soil compaction at the 0 - 30 cm depth. While no-till is a beneficial practice in northwestern North Dakota and northeastern Montana regions, additional research is needed to validate our findings on different soil types.
Technical Abstract: Tillage can significantly alter soil properties and affects crop yield and quality. A field study was conducted from 2013 to 2019 to investigate the effect of no-tillage (NT) and conventional tillage (CT) on soil penetration resistance (PR), bulk density ('b), and gravimetric water content ('m) in a 2-yr corn (Zea mays L.)-soybean (Glycine max [L.]) rotation on a Lihen sandy loam. The study was arranged in a randomized complete block design with five replications. Soil PR was measured with a digital penetrometer to a 30-cm depth at three locations after planting in crop rows within each plot. Undisturbed soil cores were sampled at the 0 - 15 and 15 - 30 cm depths to measure 'b and 'm under each tillage practice. Soil PR was significantly influenced by tillage in the 0 - 30 cm depth for the period of the study under both corn and soybean. Averaged across 0 - 30 cm depth, soil PR values were significantly lower in CT than in NT in all 7 years. Similarly, mean profile of PR across all 7 years was significantly lower in CT than in NT. Mean profile of PR averaged over 7 years resulted in higher PR of 2.027 and 2.030 MPa for NT compared to 1.118 and 1.137 MPa for CT under corn and soybean respectively. Tillage had inconsistent effect on soil bulk density and gravimetric soil water content at the 0 - 15 cm and 15 - 30 cm depths under both corn and soybean over a period of six years. Averaged over a 7-year period (2013-19), soil 'b values in the 0- 30 cm layer were significantly lower in CT (1.557, 1.578 Mg m–3) that in NT (1.631, 1.635 Mg m–3) under corn and soybean, respectively. There were no significant differences in soil 'm between two tillage systems under both corn and soybean. Lower PR and 'b values in CT under both corn and soybean may be associated with soil disturbance and inversion induced by deep tillage compared to NT management practice.