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1、耕作层变浅。农田由于长期的机械耕作碾压和人工作业,使大部分农田土壤耕层变浅,有效活土层在15公分左右,加之降雨、灌水沉实,“犁底层”上移加厚,形成了坚硬深厚的阻隔层,阻碍了土壤水分、养分和空气的上下运行,阻碍了作物根系下扎延伸,土壤蓄水能力越来越少,抗旱性能不断下降。2、土壤有机质含量降低。农田长期不施用农家肥,秸秆还田很少进行,中国传统农业精髓的种植绿肥也不搞了,土壤有机质长期得不到补充。再加上化
1, shallow farming layer. Farmland due to long-term mechanical farming and rolling and manual operations, so that most of the farmland soil tillage shallow, effective live soil layer at about 15 cm, together with rainfall, irrigation is solid, “plow the bottom ” up thickening, The formation of a hard and deep barrier, hinder the soil moisture, nutrients and air up and down the operation, hinder the crop roots under the bar extended, less and less soil water storage capacity, drought continued to decline. 2, soil organic matter content decreased. Farmland is not long-term application of manure, straw is rarely carried out, the essence of traditional Chinese farming green manure is not engaged in, long-term soil organic matter can not be added. Plus