Distribution of nutrient elements in Soil-Crop System after long-term application of zinc fertilizer

A longterm fixed experiment of application of zinc fertilizer on arid land was conducted to study the distribution of C, N, P in soilcrop system.The results shows that after 17 years continuous application of zinc fertilizer,the reaction between zinc fertilizer and nutrient such as organic matter,nitrogen and phosphorus caused different allocation of these elements in soil and crop systems.Organic matter and nitrogen contents were higher in Zn treatment in surface and subsurface soil (0~40 cm) than that in control treatment,but lower in deep soil (40~100 cm).The total phosphorus content in the whole soil profile was higher in Zn treatment than that in control treatment,while the adverse phenomenon was observed about available phosphorus content.Since zinc is necessary for plants growth,it makes crop take up more nitrogen from soil than nonzinc treatment,but absorb less phosphorous because interaction with phosphorous.Therefore,it appears different distribution of nitrogen and phosphorous in grains,shells,leaves and bines.So far as the balance of nutrient elements in soil was concerned,no matter whether zinc was used or not,nitrogen was waned and phosphorous was surplused.