Basic soil productivity in the double rice cropping system under long-term fertilization regimes in the Poyang Lake region, China.

We aimed to explore changes in basic soil productivity ( BSP) under different fertilization regimes in the Poyang Lake region, Jiangxi Province, China. Soil samples were collected from a long-term fertilization experiment (since 98) that included treatments of no fertilization (CK), chemical fertilization ( NPK), and combined chemical and organic fertilization ( NPKM) . Then, a three-year pot experiment (from 0 to 0) with double rice cropping was conducted with two different fertilization regimes (no fertilization, F₀; fertilization, F₁) using CK, NPK and NPKM soils. Grain yield and BSP were analyzed among soils with different fertilization regimes to identify the key factors driving changes in BSP. Results showed that grain yields in NPKM soil were higher than in NPK and CK soils regardless of fertilization in the pot experiment. Under the F0 condition, annual grain yields of NPKM soil were 7.7%-.9% and 0.8%-66.7% higher than CK and NPK soils, respectively. The BSP values of CK, NPK and NPKM soils in three years were .8%-5.%, 5.%-6.6% and 59.%-88.%, respectively. NPKM soil had significantly higher BSP than NPK and CK soils. Furthermore, there were significant positive correlations between soil organic matter and BSP as well as between organic carbon balance and BSP. These results suggested that long-term application of chemical and organic fertilizers could improve BSP in the double rice cropping system of the Poyang Lake region. In addition, soil organic matter and organic carbon balance are important factors for improving BSP in this region. [ABSTRACT FROM AUTHOR]