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一、棉地肥力下降情况瑞昌是赣北棉区的主要产棉县之一。全县植棉面积共8.5万亩,占耕地总面积的30％。棉地土壤的主要类型有:河、湖积冲积相潮土、下属系黄土发育的马肝土、泥质岩类风化物和第四纪红粘土形成的红壤和碳酸盐岩类风化物形成的棕灰土、红灰土等。其中红壤棉地面积约占30％,其余各类土壤大约各占15—20％。这些棉地,大部份都有20—30年的植棉历史。从目前我县棉地肥力水平情况看,除沿江滨湖和城乡居民点附近的一部份棉地肥力水平比较高外,其余还有60—70％的棉地,都程度不同地出现了肥力下降的现象。主要表现:①有机质含量降低。据本县土壤普查分析结果,棉地有机质含量比1975年前下降了0.2—0.5％。②耕作层变
First, the decline in fertility of cotton Ruichang is one of the major cotton counties in northern Jiangxi Province. The county cotton area of 8.5 million mu, accounting for 30% of the total area of cultivated land. The main types of soils in the cotton field are: alluvial-fluvial alluvial soil of the river and lacustrine sediments, red soil and carbonate rock weathering materials formed by loess-loamy soil, argillaceous and Quaternary red clay Brown lime soil, red soil and so on. Among them, the area of red soil cotton accounts for about 30%, and the remaining types of soil account for about 15-20% each. Most of these cotton fields have 20-30 years of cotton-growing history. Judging from the present situation of cotton fertility in our county, in addition to the relatively high level of fertility of some cotton fields along the riverside lakes and urban and rural residential areas, the remaining 60-70% of the cotton fields are fertile in varying degrees Falling phenomenon. Main performance: ① organic matter content decreased. According to the results of this county’s soil census analysis, the organic matter content of the cotton field decreased by 0.2-0.5% from that before 1975. ② farming layer change