Sh. Huang - Institute of Plant Nutrition, Resources and Environment, Henan Academy of Agricultural Sciences, Zhengzhou, Henan ۴۵۰۰۰۲, China.
Y. Ma - Ministry of Agriculture Key Laboratory of Plant Nutrition and Nutrient Cycling, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing ۱۰۰۰۸۱, China.
D. Bao - Institute of Plant Nutrition, Resources and Environment, Henan Academy of Agricultural Sciences, Zhengzhou, Henan ۴۵۰۰۰۲, China.
D. Guo - Institute of Plant Nutrition, Resources and Environment, Henan Academy of Agricultural Sciences, Zhengzhou, Henan ۴۵۰۰۰۲, China.

Repeated application of manures to agricultural soils could cause the accumulation of phosphorus (P) in soils. However, it is unclear if manure P can behave similar to P in soluble fertilizers in accumulation Olsen-P (0.5 mol L-1 NaHCO3 at pH 8.5) in soils. A long-term wheat-maize rotation experiment was conducted to investigate the effects of repeated application of manures on P accumulation in soils. The results showed that excessive or residual P in soils led to increase of Olsen-P in soils, which could be predicted accurately by initial concentration of Olsen-P in soils, P fertilization rate, crop yield, soil pH and cultivation time. The effects of application of K fertilizers or maize straw to soils or replacement of maize with soybean in wheat cropping systems were not significant on soil Olsen-P accumulation. The accumulation rates of soil Olsen-P were governed by P application rates of soluble P fertilizers and/or manures. Similar trend of Olsen-P accumulation was found in soils with soluble P fertilizers only or plus manures P, which supplied evidence that behaviour of manure P in long-term field soils is similar to inorganic P fertilizers and are helpful for the best management of soil P in agricultural production and environment protection.

Phosphorus, Accumulation, Long-term, soil