Effect of organic residues cycling on phosphorus nutrition in red paddy systems of south China

The effects of four different fertilization patterns, no application of P, single application of chemical P fertilizer, cycling reuse of organic residues (rice straw, pig feces and green manure) and cycling reused of organic residues incorporated with chemical P, on Olsen-P in paddy soil, P content in grain and haulm of rice as well as the P uptake and accumulation at different growth durations of rice were studied using the samples taken from a long-term experiment field of the Taoyuan Station of Agro-ecosystem Observation, Chinese Academy of Sciences. The results showed the different fertilization patterns significantly affected the content of soil available P, P uptake and the P use efficiency of rice in red paddy system of south China. Under the condition of long-term no application of P, the Olsen-P in soil decreased to a low level (less than 5 mg/kg), and Olsen P maintained at a middle level (5~10mg/kg) through single application of chemical P and cycling reuse of organic residue. However, the Olsen P was increased to a high level (higher than 10 mg/kg) through cycling reuse of organic residues incorporated with chemical P. Cycling reuse of organic residues in the ecosystem of paddy field was beneficial to promoting P uptake and accumulation and P use efficiency of rice.