[Effects of P application on P concentrations in paddy soil and its surface water: a simulation test].
An anaerobic incubation test was conducted to study the effects of different P application rate on the P concentrations in paddy soil and its surface water. The results showed that soil available P (Olsen-P) decreased rapidly at the beginning, but approached to stable after 60 days of P application. Both Olsen-P and residual P increased with increasing P application rate, and Olsen-P had a positive correlation with P application rate, suggesting that the test soil had a strong P adsorption capacity. After P application, the total P (TP) in soil surface water increased rapidly, and then decreased slowly, showing that there was a P exchange between soil and its surface water. After 120 days of P application, there was an exponential relationship between soil surface water TP and P application. The TP in soil surface water increased rapidly when the P application rate was 400 - 800 kg x hm (-2) , and easy to be lost when the P application rate was higher than 800 kg x hm(-2). The simulation with split line model on the relationship between soil Olsen-P and soil surface water TP showed that the change point of soil Olsen-P, which induced a sharp increase of soil surface water TP concentration, was 82. 7 mg x kg( -l) , corresponding to a P application rate being about 712 x kg hm(-2). Soil Olsen-P could be a good indicator in forecasting the P loss from soil surface water.
Zhou
Quanlai
Q
Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang. zhouquanlai@126.com
Zhao
Muqiu
M
Lu
Caiyan
C
Shi
Yi
Y
Chen
Xin
X
D005308:Fertilizers; D008962:Models, Theoretical; D012275:Oryza / Q000254:growth & development*; D010758:Phosphorus / Q000032:analysis*; D012987:Soil / Q000032:analysis*; D014867:Water / Q000032:analysis*; D014872:Water Movements
D005308:Fertilizers; D012987:Soil; D014867:Water; D010758:Phosphorus