Evaluating the contributions of mechanical- and bio-tillage to drought resistance in soil-crop system via energy dissipation in root water uptake
Year: 2026
Type: article
Abstract: Clayey Ultisols in humid subtropical regions exhibit contrasting water distribution during seasonal drought, with deficiency in topsoil while retaining moisture in subsoil. Although mechanical and bio-tillage practices can enhance soil water utilization and alleviate crop drought stress, quantitative methods to assess their comparative effectiveness remain limited. This study investigated the mechanisms and potential of both tillage approaches in enhancing maize drought resistance through energy dissipation associated with root water uptake ( D rwu ), using two-year field experiments in Xianning, Hubei, China. D rwu (J·s −1 ·cm −3 ), representing the energy required for roots to absorb a unit water volume, served as a quantitative indicator of tillage-modified drought resistance. Results demonstrated that mechanical tillage (MT) primarily improved soil hydraulic conductivity ( K ) and root length density (RLD) in the 10 − 20 cm layer, while bio-tillage (BT) enhanced these parameters throughout the profile and additionally improved root distribution depth index (RDDI) below 40 cm. Under equivalent root water uptake conditions, MT substantially reduced D rwu during drought by enhancing K and RLD compared to no-tillage (CK) in the 10–20 cm depth, enhancements that were associated with D rwu reductions of 83.3–90.0% and 33.5–50.0%, respectively. However, its effectiveness diminished in subsoil due to limited tillage depth. Compared to CK, BT not only reduced topsoil (0–20 cm) D rwu by 33.3–80.0%, but also enhanced subsoil (40 − 60 cm) K and RLD, enhancements that were associated with D rwu reductions of 88.9–96.2% and 66.7–80.0%, respectively. Furthermore, BT improved RDDI to 1.36 times that of CK (namely, the maximum maize root depth increased by 10 cm), which was associated with a 26.5% reduction in D rwu under severe drought, while MT showed no such benefit. Our study further indicated that yields in MT and BT treatments increased by 33 − 55% and 55 − 180%, respectively. MT showed effectiveness for alleviating mild drought stress, whereas BT demonstrated superior performance during severe drought by expanding the spatial distribution of root water uptake. This study provides practical guidance for optimizing tillage management to enhance soil-crop system drought resistance in humid subtropical climates experiencing seasonal water deficits.
Source: Geoderma
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDGs: Zero hunger, Life on land
Open Access status: gold
Estimated APC paid: $3,320
OpenAlex ID: W7160898379