机耕年限对潮土性水稻土土壤物理特性的影响

Effects of mechanical tillage years on the soil physical properties of fluvo-aquic paddy soil

  • 摘要: 农业机械化作业和耕作方式是造成耕地土壤物理性质改变的重要因素。探明江汉平原潮土性水稻土区不同机耕年限下土壤物理性质变化特征对明确区域土壤质量变化趋势, 合理改善耕层土壤结构, 选用适宜耕作措施, 促进作物增产增效具有重要意义。本文以江汉平原潮土性水稻土为研究对象, 采用田间原位模拟耕作试验, 分析了双季稻种植模式下不同耕作年限土壤物理性状的年际变化特征与趋势。结果表明: 1)土壤水分指标总体随机械耕作年限延长呈降低趋势, 犁底层以下土层(20~40 cm)总体平稳, 其中30~40 cm土层有缓慢增大趋势。2)长期机械耕作作用下, 土壤结构稳定性随耕作年限延长呈逐渐降低趋势, 土壤团聚体破碎率随剖面加深和耕作时间延长总体呈增大趋势, 土壤结构稳定性降低; 土壤紧实度随剖面加深呈先大幅增大后缓慢降低趋势, 这与长期机械作业造成的犁底层增厚和上移有关。3)在长期机械耕作下, 土壤抗压能力总体呈先增大后趋于平缓的趋势; 先期固结压力在犁底层(10~20 cm)总体呈减小趋势, 而在20~40 cm土层土壤总体呈增大趋势, 说明土壤容重和含水量是影响土壤最大抗压能力的关键因素。研究结果可为江汉平原水稻种植区土壤质量提升和农业可持续发展提供参数支持和理论依据。

     

    Abstract: Agricultural mechanization and farming methods are important factors that influence the physical properties of cultivated land. Exploring the changes in the soil physical properties in the fluvo-aquic paddy region of the Jianghan Plain over different mechanical tillage years is essential for clarifying trends in regional soil quality, reasonably improving soil structure of tillage layer, selecting suitable tillage measures, and increasing crop yield and efficiency. In this study, interannual changes in soil characteristics and trends in the physical properties of double-cropping rice planting patterns under different tillage years were simulated and analyzed using in situ simulated tillage experiments in fluvo-aquic paddy soil of the Jianghan Plain. The results showed that: 1) the soil moisture indexes decreased with increasing mechanical tillage years, was generally stable in the soil layer below the plow bottom layer (20–40 cm), and showed a slowly increasing trend in the 30–40 cm layer. 2) Under the action of long-term mechanical tillage, the stability of the soil structure gradually decreased. The breakage rate of soil aggregates increased with the deepening of the profile and the increasing mechanical tillage years, and the stability of the soil structure decreased with increasing soil depth and mechanical tillage years. The soil compactness increased with the deepening of the soil profile, thereafter decreasing slowly due to the thickening and upward movement of the plow bottom caused by long-term mechanical operation. 3) Under long-term mechanical tillage, the overall trend of soil compressive capacity increased first and then tended to be gentle. Preconsolidation pressure showed a decreasing trend in the bottom layer of the plow (10–20 cm), whereas showed an increasing trend in the lower layer (20–40 cm), indicating that soil bulk density and water content are key factors influencing the maximum compression capacity of the soil. These findings provide a theoretical basis for the improvement of soil quality in the rice-planting areas of the Jianghan Plain.

     

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