Chinese Rural Economy,No. 02
【Abstract】 In recent years, the farm size of operation units has increased a lot in China. However, due to the inadequate development in farmer training, farmland infrastructure and market-oriented reform for input factor, large-scale farmers who grow from small-scale farmers rapidly may operate their farms by using their past and less efficient methods and experience. Cost efficiency can comprehensively demonstrate the performance of one farmer with specific managerial ability operating at the specific condition of farmland infrastructure and the corresponding input market. Based on the micro panel data collected in 2015 and 2016 in Jiangsu Province, this study mainly investigated the impact of the mismatch between the farm size and efficiency on rice production costs from the perspective of cost, technical and allocative inefficiency. A two-stage instrument estimator indicated that the operation of a large farm by a small-scale farmer with low allocative efficiency and cost efficiency would lead to a slight reduction in the production cost as farm size increases. This may suppress the effects of economies of scale. The empirical results also showed that the farm size for cost minimization in the sample is between 100 and 150 mu. The study concluded with some policy implications.
Chinese Bulletin of Botany,Vol 54,No. 04
【Abstract】 The premise of studies on rice chilling tolerance is to find an efficient and accurate way to evaluate the chilling tolerance of rice seedlings. In this study, we developed an efficient technology to evaluate the cold tolerance at seedling stage by using a constant temperature water bath, based on the characteristics of excellent temperature uniformity for circulation of water. In this method, the setting temperatures of environment temperature and water bath were 20 °C and 4 °C, respectively. From the results of two subspecies ( indica/ xian and japonica/ geng), we summarized the reference treatment time for different survival rate of cultivars. Some attention to the cold treatment procedure was also discussed.
Acta Agronomica Sinica,Vol 45,No. 11
【Abstract】 The 550 rice germplasms collected from different regions were tested 10 days after transplantation and treated with salt of variation concentration gradients (0, 0.3%, and 0.5% salt) during the whole growth period. The salt of different concentration gradients was prepared with different volumes of water and seawater. Six agronomic traits, including plant height, panicle number per plant, main panicle length, seed setting rate, yield per plant and heading date, were investigated under 0 and 0.3% salt treatments, and the salt tolerance phenotype was investigated under 0.5% salt treatment. Under treatment of 0.3% salt in the whole growth period, the plant heights of 550 (100%) rice varieties were decreased significantly. There was significant difference in panicle numbers per plant of 124 (90 up, 34 down) rice varieties, main panicle lengths of 414 (405 down, 9 up) rice varieties, seed setting rates of 145 (84 down, 61 up) rice varieties, yields per plant of 375 (343 down, 32 up) rice varieties and no significant difference in heading date. The principal component analysis showed that 77.25% variation was contributed by the three agronomic traits including main spike seed-setting rate, effective tiller number, and yield per plant. A total of 121 salt-tolerant rice varieties with yield salt tolerance coefficient ≥ 0.8 were obtained under 0.3% salt treatment and 78 salt-tolerant rice varieties with salt tolerance phenotype of level 3 were screened under the 42-day 0.5% salt treatment. There were 25 rice varieties with both the yield salt tolerance coefficient ≥ 0.8 under 0.3% salt treatment and phenotype of level 3 under the 42-day 0.5% salt treatment. These salt-tolerant varieties can be used for cultivar innovation and the further study on the mechanism of salinity tolerance.