Impacts of Various Straw Mulching Strategies on Soil Water, Nutrients, Thermal Regimes, and Yield in Wheat–Soybean Rotation Systems
Straw mulching is an important strategy for regulating soil moisture, nutrient availability, and thermal conditions in agricultural systems. However, the mechanisms by which the mulching period, thickness, and planting density interact to influence yield formation in wheat–soybean rotation systems r...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Plants |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2223-7747/14/14/2233 |
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| Summary: | Straw mulching is an important strategy for regulating soil moisture, nutrient availability, and thermal conditions in agricultural systems. However, the mechanisms by which the mulching period, thickness, and planting density interact to influence yield formation in wheat–soybean rotation systems remain insufficiently understood. In this study, we systematically examined the combined effects of straw mulching at the seedling and jointing stages of winter wheat, as well as varying mulching thicknesses and soybean planting densities, on soil properties and crop yields through field experiments. The experimental design included straw mulching treatments during the seedling stage (T<sub data-eusoft-scrollable-element="1">1</sub>) and the jointing stage (T<sub data-eusoft-scrollable-element="1">2</sub>) of winter wheat, with soybean planting densities classified as low (D<sub data-eusoft-scrollable-element="1">1</sub>, 1.8 × 10<sup data-eusoft-scrollable-element="1">5</sup> plants·ha<sup data-eusoft-scrollable-element="1">−1</sup>) and high (D<sub data-eusoft-scrollable-element="1">2</sub>, 3.6 × 10<sup data-eusoft-scrollable-element="1">5</sup> plants·ha<sup data-eusoft-scrollable-element="1">−1</sup>). Mulching thicknesses were set at low (S<sub data-eusoft-scrollable-element="1">1</sub>, 2830.19 kg·ha<sup data-eusoft-scrollable-element="1">−1</sup>), medium (S<sub data-eusoft-scrollable-element="1">2</sub>, 8490.57 kg·ha<sup data-eusoft-scrollable-element="1">−1</sup>), and high (S<sub data-eusoft-scrollable-element="1">3</sub>, 14,150.95 kg·ha<sup data-eusoft-scrollable-element="1">−1</sup>), in addition to a no-mulch control (CK) for each treatment. The results demonstrated that (1) straw mulching significantly increased soil water content in the order S<sub data-eusoft-scrollable-element="1">3</sub> > S<sub data-eusoft-scrollable-element="1">2</sub> > S<sub data-eusoft-scrollable-element="1">1</sub> > CK and exerted a temperature-buffering effect. This resulted in increases in soil organic carbon, available phosphorus, and available potassium by 1.88−71.95%, 1.36−165.8%, and 1.92−36.34%, respectively, while decreasing available nitrogen content by 1.42−17.98%. (2) The T<sub data-eusoft-scrollable-element="1">1</sub> treatments increased wheat yields by 1.22% compared to the control, while the T<sub data-eusoft-scrollable-element="1">2</sub> treatments resulted in a 23.83% yield increase. Soybean yields increased by 23.99% under D<sub data-eusoft-scrollable-element="1">1</sub> and by 36.22% under D<sub data-eusoft-scrollable-element="1">2</sub> treatments. (3) Structural equation modeling indicated that straw mulching influenced yields by modifying interactions among soil organic carbon, available nitrogen, available phosphorus, available potassium, bulk density, soil temperature, and soil water content. Wheat yields were primarily regulated by the synergistic effects of soil temperature, water content, and available potassium, whereas soybean yields were determined by the dynamic balance between organic carbon and available potassium. This study provides empirical evidence to inform the optimization of straw return practices in wheat–soybean rotation systems. |
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| ISSN: | 2223-7747 |