Chemical fertilizers input and soil nutrient resources in winter wheat-corn rotation system in Huantai County

This paper deals with the chemical fertilizer input and soil nutrient resource in winter wheat-corn rotation system in Huantai County of Shandon4g Province．The results show that form 1990 to 1996，after one-ton-yield county is established in 1990，the average annual rates ofnitrogen，phosphorus(P₂0₅)and potassium(K₂O)fertilizers are 599．4±64．8kg／hm²，211．0±26．4k/hm²，103．6±21．2kg／hm²，respectively；and N：P₂0₅：K₂O ratio is 1：0．353(±0．033)：0．176(±0．046)．It is also shown that from 1990 to 1996，the average contents of soil organic matter，alkaline hydrolysable nitrogen，available phosphorus(P) and available potassium (K)are 14．6±0．3g／kg，64．2±2．9mg／kg，8．5±1．5mg／kg and 83．8±8．2mg／kg，showing that irratiohal strueture of fertilizer input occurs in Huantai County，and we should decrease its nitrogen input，maintain current phosphorus level and increase the input of potassium fertilizer in Huantai County．