不同耕作深度对红壤坡耕地耕层土壤特性的影响

红壤坡耕地不同耕作深度对耕层质量和作物产量具有重要影响。以江西红壤坡耕地示范区耕层为研究对象,从土壤属性角度,对红壤坡耕地不同耕作深度处理下垂直深度土壤水分、容重、孔隙度、土壤紧实度、土壤抗剪强度、土壤有机质、有效磷和速效钾等进行分析。结果表明:(1)不同耕作深度对土壤孔隙度、饱和含水量和田间持水量的影响为免耕翻耕20 cm翻耕10 cm常规耕作翻耕30 cm,对容重的影响为翻耕30 cm常规耕作翻耕10 cm免耕翻耕20 cm;与常规耕作比较,翻耕30 cm使土壤饱和含水量、田间持水量和土壤孔隙度分别提高了18.17%,12.67%,5.94%,土壤容重降低6.90%。(2)不同耕作深度下土壤紧实度表现为翻耕30 cm翻耕10 cm翻耕20 cm免耕常规耕作,土壤抗剪强度表现为翻耕30 cm常规耕作翻耕10 cm免耕翻耕20 cm;与常规耕作对照,翻耕30 cm使土壤紧实度和抗剪强度分别降低27.07%和24.82%。(3)土壤有机质含量以翻耕20 cm处理下最高(13.48 g/kg),免耕处理含量最低(9.39 g/kg),土壤速效养分主要集中分布在0-20 cm土层,但20-40 cm土层中翻耕处理较免耕处理有不同程度的增加,以翻耕20 cm和常规耕作表现显著。(4)主成分分析结果表明,翻耕30 cm处理对红壤坡耕地土壤的综合改善效果最好。研究结果可为红壤坡耕地耕层土壤改善和合理耕层构建提供技术参考。

Effect of Different Tillage Depth on Soil Properties of Ploughing Layer in Slope Cultivated Land of Red Soil

The different tillage depth of red soil slope farmland has an important effect on the quality of ploughing layer and crop yield. From the point of view of soil properties, the vertical depth soil moisture, bulk density, porosity, soil compactness, soil shear strength and soil organic matter under different tillage depth treatments in red soil slope cultivated land were studied in Jiangxi Province. Available phosphorus and available potassium were also analyzed. The results showed that:(1) The effects of different tillage depth on soil porosity, saturated water content and field water holding capacity were no tillage < tillage 20 cm < tillage 10 cm < conventional tillage < tillage 30 cm, the effect on bulk density was tillage 30 cm < conventional tillage < tillage 10 cm < no tillage < tillage 20 cm; compared with the conventional tillage, the soil saturated water content, field water holding capacity and soil porosity were increased by 18.17%, 12.67% and 5.94%, respectively after 30 cm tillage. Soil bulk density decreased 6.90%. (2) The soil compactness under different tillage depths was tillage 30 cm < tillage 10 cm < tillage 20 cm < no tillage < conventional tillage; soil shear strength was tillage 30 cm < conventional tillage < conventional tillage 10 cm < no tillage 20 cm. Compared with the conventional tillage, ploughing for 30 cm reduced soil compactness and shear strength by 27.07% and 24.82%, respectively. (3) The average content of soil organic matter was the highest under 20 cm tillage (13.48 g/kg), and lowest under no tillage treatment (9.39 g/kg). Soil available nutrients were mainly distributed in 0-20 cm soil layer. Compared with the no tillage treatment, soil available nutrients contents increased under the tillage treatments, among which tillage 20 cm and conventional tillage gave the significant differences. (4) The results of principal component analysis showed that the treatment of tillage 30 cm had the best effect on the comprehensive improvement of soil properties in red soil slope cultivated land. These results could provide reference for the improvement of ploughing layer soil and the construction of rational tillage layer in slope cultivated land of red soil.