Effects of modified fertilization technology on the grain yield and nitrogen use efficiency of midseason rice

Abstract Local popular midseason varieties of rice were used to study the effects of modified fertilization technology on the grain yield and nitrogen (N) use efficiency of midseason rice in central China. Field trials with five N treatments and four replications were conducted in Jingmen County (2008–2009), Honghu County (2009–2011), and Chibi County (2008–2011) in Hubei Province. The results showed that, relative to most farmers’ fertilizer practices (FFP), the grain yield of modified farmers’ fertilizer practices (MFP) in eight out of nine experiments showed an increase in ratio ranging from 0.3% to 16.6% and grain yield of super-high-yield fertilizer practice (SHY) in six of nine experiments showed an increase in ratio ranging from 2.4% to 20.9%. Relative to SHY, the grain yield of modified super-high-yield fertilizer practice (MSP) treatments in seven out of nine experiments showed an increase in ratio ranging from 0.2% to 20.4%. Relative to FFP, the nitrogen agronomic efficiency (NAE) and nitrogen physiological efficiency (NPE) values of MFP treatment in eight out of nine experiments showed an increase in ratio ranging from 26.0% to 110.3% and from 1.3% to 46.1%, respectively. Relative to SHY, the NAE and NPE values of MSP treatment in eight out of nine experiments showed an increase in ratio ranging from 5.2% to 151.7% and from 7.4% to 82.6%, respectively. Further analysis showed that the number of panicles in MFP, SHY, and MSP were greater than in FFP. This was attributable to the ability of the modified fertilizer technology to delay functional leaf senescence, maintain optimum leaf area index (LAI), an optimize shoot biomass, to a reasonable tiller number and to a healthy population structure with a high relative amount of productive tiller. This study may provide technical and theoretical support for simultaneously increasing rice grain yield and nutrient use efficiency, for optimization of the use of fertilizer by local farmers, and for facilitating sustainable increases in grain yield.