Comparison and evaluation of different rice mechanized transplanting methods in double cropping area of South China

Abstract: In order to find the adaptability and influence mechanism of different mechanized rice transplanting methods in double cropping area of South China, the comparison tests of three kinds of mechanized transplanting methods are arranged in Jiangmen City and Zhaoqing City of Guangdong Province from 2011 to 2014. In this study, the three mechanized transplanting methods are mechanized transplanting with pot-grown flat seedling, mechanized transplanting with flat seedling and mechanized transplanting with narrow row flat seedling. The method of transplanting by hand is used as the control. Transplanting methods, environment and their interactions are analyzed by AMMI (additive main effects and multiplicative interaction) model, and the stability and adaptability of different rice transplanting methods are evaluated. The results show that: Firstly, according to the results of one way ANOVA of rice yield under different transplanting methods, it is found that there are four times the yield difference is not significant and one time significant at 0.05 level in five comparison tests of conventional rice. In the significant test, the yields of all three kinds of mechanized transplanting methods are higher than the yield of transplanting by hand. This proves that all three kinds of mechanized transplanting methods have good adaptability on conventional rice, and can replace the method of transplanting by hand for large-scale use. Moreover, it is found that there are four times the yield difference is significant at 0.05 level and one time not significant in five comparison tests of hybrid rice. In the significant test, the yields of all three kinds of mechanized transplanting methods are lower than the yield of transplanting by hand. Therefore, mechanized transplanting technology for hybrid rice needs further study. Secondly, the sum of squares of transplanting methods, the sum of squares of environment and the sum of squares of the two's interactions are 6.39%, 8.31% and 85.29% of total sum of squares respectively. All of them have achieved significant difference at 0.05 level from AMMI model analysis. The former two of IPCA (interaction principal component analysis) explain 92.99% of the sum of squares of the interactions. The value of residual root mean square is 49.34 kg/hm2, and it is 0.71% of population mean. This means that AMMI2 model can well explain the experimental data's structure. The AMMI model is a good method for evaluating the stability and adaptability of different transplanting methods. Thirdly, the method of transplanting by hand is the best way of hybrid rice planting at present, the yield of which is the highest, and there is a big positive environment interaction. But the stability of this method is not good. The stability of mechanized rice transplanting with flat seedling is the best, the yield of which is yet the lowest. The stability of mechanized rice transplanting with pot-grown flat seedling is less than mechanized rice transplanting with flat seedling, but the yield of the former is higher, which is improved by about 2%-6% compared with mechanized rice transplanting with flat seedling. The stability of mechanized rice transplanting with narrow row flat seedling is less than mechanized rice transplanting with pot-grown flat seedling, but the yields of them are almost equal. The yield of mechanized rice transplanting with narrow row flat seedling is often higher than mechanized rice transplanting with pot-grown flat seedling in late hybrid rice. Research conclusions have important reference value for promoting the development of planting mechanization in the rice cropping areas of South China.