- The content of total N and total P in rainfall could be increased by Pinus tabulaeformis and Rhus typhina.
- The content of Total N, Total P and Total K of Cole respectively increases 16.8%, 20.7%, 8.5% comparing with the area of reference.
- The results showed that organic matter (OM), total N and alkali-hydrolyzable N enriched apparently, but total P and available P did not enrich.
- The contents of total N, total P and OM were closely related to combined humus, but the contents of total K and CEC were not.
- Corn economic yield and biological yield were significantly related with soil organic matter, total N, alkali-hydrolyzable N, total P, and availabl P.
- 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.