Based on the long-time location exeriments,accumulation and distribution of available sulfur in soil of different cropping systerms under the condition of 22 years continuous application of NP chemical fertilizer in Loess Plateau were studied.

The field experiment on effect of spent mushroom compost applied with NPK fertilizers on the growth of cowpea showed that the combination of spent mushroom compost with NPK fertilizers extreme significantly increased the yield of cowpea by 362.