Based on data of 9 years field position test

we analysed the soil nutrient's change ofthree Helu soil layer under different treatments of fertilization.The results showed that the effectof fertilization on Helu soil layer's nutrient decreases with depth increasing(generally

0～20cm20～50cm 50～80cm).The nutrient's difference of topsoil is the biggest under differenttreatments

even though the nutrient's difference of the layers below topsoil is on the decrease

but their change tendency is the same as topsoil's.Compared with rare land

available nutrient ofsoil layers under CK are decreased.To evaluate comprehensively

the effect that different treat-ments improved soil fertility is NPMMPM