Study on high efficiency nutrient use and regulation of soil nutrient dynamics for high yield rice
IPNI-2010-CHN-HN16
01 Mar 2010
2009 Annual Interpretive Summary
Efficient Nutrient Use and Regulation of Soil Nutrient Dynamics for High Yield Rice, 2009
Fertility characteristics of highly productive paddy soils were studied as part of a science-based approach to sustainable utilization of paddy soils. Organic matter fractions (total and labile) and nutrient contents (total and available) and their relationships with rice yield were investigated within double-rice cropping systems located in eight important rice production counties in Hunan.
Highly productive paddy soil under double-rice had organic matter contents of 47.7±11.59 g/kg, total N of 2.70±0.72 g/kg, and available P of 39.8±14.21 g/kg. Contents of organic matter, total N, and available P in moderately productive paddy soils were not significantly different compared to these highly productive soils. The less productive soils did have significantly lower values for all soil properties listed compared to both high and mid-productivity soils. Fertilizer P in the high productivity soil was more mobile and could be easily moved to water bodies, and thus become a source of eutrophication. Available soil K contents in high productivity soils were in the mid-range (108.8±22.8 mg/kg). The contents of soil organic matter, total N, and available P were very high in high productivity soil because of long-term rice cultivation and its fertilization. Both the organic matter and P pools were in surplus status. The texture of high productivity soils were generally loamy to sandy clay loam dominated by kaolinite with a weak K retention capacity. Attention should be paid to the rational application of K fertilizer and rice straw recycling to maintain or improve the soil K balance in high productivity soils. For most mid-productivity soils, due to their relatively high contents of organic matter, total N, and available P, rice yields equal to those obtained in high productivity soils could only be achieved with good field management practices. The physical properties and nutrient status in low productivity soils are limiting yields and rational application of manure and inorganic fertilizers are required to remove the yield barriers in these soils. Hunan-16