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2.农业土壤生态系统 我省农田(地)就当前的生产水平而论,约有30～40％缺氮,40～50％缺钾,60～70％缺磷。与第一次土壤普查时(1958～1960年)相比,部分农田(地)土壤理化性质恶化,肥力下降。表现在有机质、氮、磷、钾养分含量降低,比例失调,酸度增大,耕层板结,次生潜育化加剧。例如九江地区土壤有机质含量第一次土壤普查时多为1.5～2.0％,现湖口县水田有机质含量在1％左右的占1/3,旱地有机质在1％以下的占一半。湖口、星子、彭泽三县耕地土壤普遍缺磷,有效磷含量只有5～10ppm,高产
2. Agricultural Soil Ecosystem In terms of the current production level, about 30-40% of the farmland (field) in our province is deficient in nitrogen, 40-50% is deficient in potassium and 60-70% is deficient in phosphorus. Compared with the first soil survey (1958 ~ 1960), the physical and chemical properties of soil in some fields (fields) worsened and the fertility decreased. The results showed that the contents of nutrients, nitrogen, phosphorus and potassium in the organic matter decreased, the imbalanced proportion increased, the acidity increased, the compaction of plow layer and the secondary glancing intensified. For example, in the first soil survey of soil organic matter in Jiujiang, the soil organic matter content is mostly 1.5-2.0%. Now the organic matter content of Hukou County paddy soil accounts for about 1%, while that of dry land is less than 1%. Hukou, Xingzi, Pengze three counties generally lack phosphorus soil, available phosphorus content of only 5 ~ 10ppm, high yield