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Discussion on the Theory and Methods for Determining the Target Yield in Rice Production

2015; Linguagem: Inglês

0578-1752

Zou Ying-bi,

Rice Cultivation and Yield Improvement

【Objective】The aim of this study was to discuss the theory and methods for determining the target yield in rice production. 【Methods】The discussion and analysis were based on the results of field experiments conducted in five locations(Chengmai of Hainan Province, Huaiji of Guangdong Province, Binyang of Guangxi Province, Changsha of Hunan Province, and Xingyi of Guizhou Province) in South China with different N application rates(zero N application; moderate N rate: 161—176 kg·hm-2; high N rate: 225 kg·hm-2) and varieties(hybrid varieties Liangyoupeijiu and Y-liangyou 2 and inbred varieties Huanghuazhan and Yixiangyouzhan) in 2012 and 2013, and the reports of relevant literature in China and abroad.【Results】The field experiments showed that the yield performance of even the same rice variety exhibited significant or extremely significant differences among the five locations. Under N application conditions(moderate and high N rates), Xingyi had the highest average yield(Liangyoupeijiu: 13.20-13.54 t·hm-2, Y-liangyou 1: 13.50-13.78 t·hm-2, Huanghuazhan: 11.26-11.42 t·hm-2, Yuxiangyouzhan: 11.32-11.45 t·hm-2), followed by Changsha, Chengmai, Binyang, and Huaiji had the lowest average yield(Liangyoupeijiu: 6.66-6.71 t·hm-2, Y-liangyou 1: 6.96-7.20 t·hm-2, Huanghuazhan: 6.96-7.11 t·hm-2, Yuxiangyouzhan: 7.35-6.86 t·hm-2). Similarly, the highest average soil-based yield(yield of no N application treatment) was recorded in Xingyi(10.52 t·hm-2), followed by that in Changsha, Chengmai and Binyang, and the lowest average soil-based yield was recorded in Huaiji(4.53 t·hm-2). The rice yield under fertilized conditions(namely fertilized yield)(YF) depended extremely significantly on the soil-based yield(YS). The regression equations under moderate and high N rates were YF=0.814YS+3.337(R2=0.824) and YF﹦0.864YS+3.094(R2=0.839), respectively. The contributions of the soil-based yield(the percentage of the soil-based yield in the fertilized yield) ranged from 64.8% to 85.5% on the average of five locations and from 72.7% to 79.3% on the average of four varieties. The analysis of the data(n=315) collected from previous studies also indicated that there was a significant positive linear relationship between the soil-based yield and the fertilized yield(YF=1.031YS+2.421, R2=0.523), and the average contribution of the soil-based yield was 67.7%. In addition, the results showed that yield increased by fertilization was tightly negatively related with soil-based yield contribution; grain yield was significantly quadratically related to plant N uptake and N application rate.【Conclusions】Target yield should be varied from site to site. Soil-based yield comprehensively reflects the paddy soil fertility and the climate productivity, and therefore can be used as the basis to determine the target yield in rice production. The target yield for high yielding cultivation of rice can be determined by the regression equation based on the soil-based yield. Improving soil fertility is an important approach for achieving the target yield.