Soil total P decreased linearly with time for gray desert soil, paddy soil and fluvo-aquic soil, but did not change significantly for other soils.

• 在试验进行5年左右，土壤全磷含量都有所降低，以后各点表现不尽相同，新疆灰漠土、长沙水稻土和郑州潮土全磷含量随时间延长呈显著直线下降，其它试验点全磷的变化不明显；