洞庭湖集约农区自８０年代以来，随着耕作制度的改革，吨粮田的开发，高产耐肥品种的推广，特别是杂交水稻的普及推广，复种指数显著增加，绿肥种植面积显著缩小，有机肥料投入越来越少，导致农作物摄走的养分增加，引起稻田土壤肥力，特别是土壤有机质和磷、钾养分含量不... Intensive farming areas in Dongting Lake Since the 1980s, with the reform of the farming system, the development of the grain fields, the promotion of high-yield and anti-fertilizer varieties, especially the popularization and popularization of hybrid rice, the index of multiple cropping increased markedly and the acreage of green manure was significantly reduced. Fewer and fewer fertilizer inputs, resulting in increased nutrient intake of crops, causing paddy soil fertility, especially soil organic matter and phosphorus, potassium nutrient content is not ...