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土壤侵蚀会降低生产力,威胁农业生产,因此,对土壤生产力进行恢复和评价具有重要意义。通过人工剥离熟土层,模拟研究不同侵蚀程度下的土壤生产力,选取施肥和覆盖表土2种恢复措施,对其土壤生产力的恢复情况展开研究并进行评价。结果表明:1)土壤侵蚀能够使土壤的理化性状恶化,施肥和覆土均能很好地改善土壤密度和孔隙度等,并能够增加土壤有机质及其他养分的质量分数。2)土壤侵蚀会降低作物产量,在不施肥下,每侵蚀1cm熟土层,玉米产量平均下降1.27%,施肥下每侵蚀1 cm熟土层,玉米产量比对照平均增加0.87%;而每覆盖1cm熟土层,玉米产量平均增加0.91%,但并不能完全补偿侵蚀造成的产量损失。3)利用土壤生产力指数模型(PI模型)计算出了不同措施下的生产力指数,发现:无肥下侵蚀的生产力指数最低,平均每侵蚀1 cm熟土层,生产力指数下降2.17%,施肥下平均每侵蚀1 cm熟土层,生产力指数比无肥增加1.09%,而平均每覆盖1 cm熟土,生产力指数增加1.29%;表明覆土较施肥更易提高土壤生产力。4)对产量和生产力指数进行相关性分析,得出二者具有很好的正相关关系,说明用生产力指数来衡量土壤生产力的高低是可行的。
Soil erosion can reduce productivity and threaten agricultural production. Therefore, it is of great significance to recover and evaluate soil productivity. By manually stripping the mature soil layer, simulating the soil productivity under different erosion levels, two kinds of recovery measures of fertilization and topsoil were selected, and the recovery of soil productivity was studied and evaluated. The results showed that: 1) soil erosion could degrade the physicochemical properties of soil, soil fertility and soil cover could both improve soil density and porosity, and increase the mass fraction of soil organic matter and other nutrients. 2) Soil erosion would reduce the crop yield. Under no fertilization, the yield of maize decreased by 1.27% on average for every erosion of 1 cm soil layer. The yield of maize increased by 0.87% on average per 1 cm soil layer under fertilization; 1 cm soil layer, corn production increased by an average of 0.91%, but does not fully compensate for the loss of yield caused by erosion. 3) The productivity index under different measures was calculated by using the soil productivity index model (PI model). It was found that the productivity index under non-submergence erosion was the lowest, and the productivity index decreased by 2.17% per 1 cm soil layer erosion on average. The productivity index increased by 1.09% per 1 cm soil layer per 1 cm eroded soil, while the productivity index increased by 1.29% per 1 cm soil cover, indicating that soil cover was easier to increase soil productivity than fertilization. 4) Correlation analysis between yield and productivity index shows that the two have a good positive correlation, which shows that it is feasible to measure the productivity of soil with the index of productivity.