ABSTRACT
Routine fertilization refers to nitrogen, phosphorus and potassium are used the local average fertilizer application, fertilization mode, and distribution proportion. The amount of routine fertilization is N 136.5 kg ⋅ hm−2, P2O5 67.5 kg ⋅ hm−2, K2O 67.5 kg ⋅ hm−2; Optimize fertilization is recommended fertilization method based on research object in the
1 INTRODUCTION
Rice is the major grain crop of the world, especially in southeastern China (Zhu et al, 2009). Reasonable irrigation and fertilization are the two most important measures to increase rice yield and quality (Zhang et al, 2007; Li et al, 2010). However, farmers’ blind application of large number of fertilizers to pursuit higher yields in recent years caused negative ecological effects of nitrogen and phosphorus accumulation which was much larger than the crop yield increment (Tian et al, 2010). Paddy field was become an important agricultural nonpoint source pollution sources with various factors such as irrational flood irrigation. There are some researches on fertilization and non-point source pollution from paddy field have been reported at present (Huang et al, 2013), but there are not less study on irrigation (Chen et al, 2009). The study on water and fertilizer coupling measures to control agricultural non-point source pollution from paddy field is seldom (Chen et al, 2011). Under the condition of natural rainfall and through the field monitoring runoff in experiment plots for 5 years (or 10 stubbles of rice), the effect on concentration and loss load of nitrogen and phosphorus with 6 kinds of water and fertilizer managements was studied in paddy field. Results concluded from this study would provide some scientific gist to evaluate and reduce non-point source pollution from paddy
local where the amount is N 120 kg ⋅ hm−2, P2O5 60 kg ⋅ hm−2, K2O 120 kg ⋅ hm−2; Increasing nitrogen (phosphorus) fertilization is defined that nitrogen (phosphorus) fertilizer application increases 50% on the basis of optimize fertilization, while the quantity of phosphorus (nitrogen) and potassium fertilization is the same with optimize fertilization; Routine irrigation is defined that surface-field water level is kept in the range of 1∼6 cm during rice planting, except paddy field drainage period; water-saving irrigation is defined that surface-field water level is kept in the range of −3∼3 cm during rice planting, except paddy field drainage period; Each treatment was repeated three times. The area of each plot was 20 m2, which was randomly aligned.
