双季稻收割时稻谷含水量的差异及原因分析

Differences in Water Content in Grains at Harvesting Stage and Its Causes Analysis in Double Cropping Rice

收集了2008年湖南省18个高产创建县早稻和晚稻收割时的稻谷样品共321个，在恒温80℃条件下测定了所有稻谷样品的含水量、秕粒重和稻谷净干率。结果发现：①稻谷样品净干率差异大．其中早稻为80．2％，变幅为62．1％～94．5％。晚稻为83．9％，变幅为70．7％～96．9％；②稻谷含水量与净干率成显著负相关．与秕粒／实粒重量成显著正相关，而秕粒／实粒重量与净干率成显著负相关。由于收割时稻谷外壳已风干，同时去除了空粒和部分秕粒，由此推测稻谷样品含水量的差异是由于秕粒所占比重不同导致的，而秕粒为未成熟籽粒．是由于割青所造成的。

324 rice grain samples of early and late rice were gathered from 18 high-yielding counties of Hunan province in 2008 and their water content, weight of unfilled grains anti percent of net dry grain were measured under 80℃ in drying oven. The results showed that the percent of net dry grain of early rice averaged as 80. 2% and changed in 62. 1%- 94.5%, and that of late rice averaged as 83.9% and changed in 70. 7%-96.9%. Significant negative correlation existed between water content in grains and the percent of net dry grain, and significant positive correlation existed between water content in grains and the ratio of unfilled grain weight to filled grain, while significant negative correlation was observed between the ratio of unfilled grain weight to filled grain and the percent of net dry grain. Because the grain crust was dried by wind before harvesting and the empty grains and part of unfilled grains were wiped off after harvesting, the difference in water content of grain samples resulted from the different percent of unfilled grains in samples. In fact, the unfilled grains were the immature grains which resulted from harvesting ahead of time.