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太湖地区是我国著名的高产区之一。近几年来,随着“双三制”面积的扩大和改制年限的增长,不少田块的土壤性质恶化,这是当前发展农业生产急待解决的问题之一。 一、水稻土性质的变化 “双三制”发展以后,由于措施没有跟上,水稻土性质发生了以下变化: 1.耕层土壤结构变差,土块发僵,微团聚体的数量和质量是判断水稻土结构好坏的重要指标,1977年测定表明,1965年以来苏州地区水稻耕层内的微团聚体明显减少,特别是1～0.25和0.25～0.05毫米两级微团聚体的含量,1977年比1965年要低10～20%,1977年耕层内50%的微团聚体直径比1965年要小11×10~(-3)到6×10~(-3)。高产水稻土耕层麦季的容重一般小于1.20,总孔隙度大于55%。从吴县金山公社土壤普查测定结果看,容重一般超过1.25,总孔隙度不到50%。从勇气孔隙的数量看,据1974年麦季无锡
The Taihu Lake region is one of China’s famous high-yield areas. In recent years, with the expansion of “double-three system” and the increase in the number of years of restructuring, the soil properties of many fields have deteriorated. This is one of the urgent problems to be solved in the current development of agricultural production. Changes in the nature of paddy soil After the development of the “double-three system”, due to the failure to keep up with the measures, the following changes have taken place in the properties of paddy soil: 1. The structure and quality of paddy soil deteriorate, the soil mass becomes stiff, and the quantity and quality of microaggregates It is an important index to judge the structure of paddy soil. The results of 1977 test show that the microaggregates in paddy soils of Suzhou area decreased obviously since 1965, especially the content of two microaggregates of 1 ~ 0.25 and 0.25 ~ 0.05 mm, In 1977 it was 10-20% lower than in 1965. In 1977, 50% of the microaggregates in the tillage were 11 × 10 -3 to 6 × 10 -3 smaller than those in 1965. The bulk density of high-yielding paddy tillage is generally less than 1.20 and the total porosity is greater than 55%. According to the results of the soil census survey of Jinshan commune in Wuxian County, the bulk density generally exceeds 1.25 and the total porosity is less than 50%. From the courage to see the number of pores, according to Mak quarter 1974, Wuxi