What's worse, the eroded soil is chiefly high-quality topsoil. A mainland article in 1985 estimated that 40 million tons of nitrogen, potassium, sulfur, and other natural fertilizers are washed away each year--more than the total quantity of fertilizers applied annually.
流失的土還有許多是「土中之土」﹘﹘單位土地上品質最佳的土，一九八五年大陸出版的「環境科學」六卷六期中，任耐安所寫的「試論我國生態農業」文內估計，每年流失的水土中，含有氮、鉀、磷等天然肥料四千萬噸﹘﹘超過大陸每年所施化肥總量。