The sustained 8 years field experiments and laboratory analysis shows the increasingyield effect of organic matter mixed with chemical fertilizer is higher than that of organic matter or chemical fertilizer,and organic matter effect mixed with N is high, its mixed with P is low,its mixed with N and P is very high. Organic matter mixed with chemical fertilizer may improve soil fertility with best effect as it mixed with N and P. Soil available P is increased as applying P and soil nutrient change is not obvi...
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