Bioscience Methods 2026, Vol.17, No.1, 23-31 http://bioscipublisher.com/index.php/bm 24 experiment was conducted directly in the field. By setting different harvest times, the moisture content of the grains, the whole grain milling rate, and the eating quality were measured respectively. These results were then compared together to see if the changes were synchronous. Unlike previous discussions that broke down the issues separately, here an integrated analysis approach was adopted, combining factors such as moisture content, processing effects, and eating quality. This was done in conjunction with the actual responses of specific varieties to verify the results. The purpose of this approach is also quite clear; it is to make the experimental results more closely align with actual production conditions, and at the same time, provide more practical references for the harvesting management of high-quality rice. 2 Changes in moisture content of rice during different harvest periods 2.1 Dynamic changes in moisture content during the ripening process of rice grains During the later growth stage, the moisture content in the rice does not drop all at once; instead, it changes gradually. For instance, during the milk stage, the moisture content in the grains is still relatively high. Only when the filling process continues does the moisture content start to decrease. In the late wax ripening stage, this decrease becomes more pronounced. When approaching full maturity, the moisture content often drops to around 20%. In actual production, it is not necessary to wait until complete maturity to plant the rice. It is generally more suitable to do so between the end of the wax ripening stage and the early stage of full ripening. At this time, the moisture content of the grains is mostly between 20% and 25% (Zhou et al., 2025). At this point, the rice has turned yellow in color, the grains are plump and have a hard texture, and the moisture content is relatively stable. Whether for harvesting or subsequent processing, this is more convenient (Teng et al., 2024). 2.2 Differences in the impact of different harvesting periods on grain moisture content In actual production, the moisture content of grains varies significantly depending on the time of harvest. Generally, the moisture content of rice harvested earlier is the highest, while at the appropriate harvesting stage, the moisture content of the grains is usually around 20%; if the harvest is further postponed, the moisture content will further decrease, even dropping below 15% (Zhou et al., 2025). Field management experience also indicates that rice with excessive moisture is not conducive to later storage, and rice with insufficient moisture can also cause problems (Wang et al., 2022). Both harvesting too early or too late carry risks. Therefore, in production practice, the harvesting time needs to be flexibly adjusted according to the changes in grain moisture content to maintain it within a relatively appropriate range, so as to avoid increasing drying costs or having adverse effects on quality. 2.3 Relationship between moisture content changes and meteorological factors Once the grains reach the mature stage, the changes in moisture content tend not to be as predictable as expected. They do not always follow the growth process all the way down. Instead, weather becomes a crucial factor. For instance, when there are many sunny days and the air is dry, the grains lose moisture at a significantly faster rate. However, if there are several consecutive rainy days, the moisture content may be pulled back (Thompson et al., 2022). There is another situation that is often overlooked. When the moisture content has dropped below 16%, and then comes rain or dew to absorb moisture again, cracks are more likely to appear inside the rice grains, and the whole rice purity rate will also be affected (Figure 1) (Brinkhof et al., 2025). Therefore, when determining the harvest time, one should not only consider the maturity level but also pay more attention to weather changes. Try to avoid periods when rain occurs in concentrated bursts and reduce the adverse impact of significant fluctuations in moisture content on the quality of the rice. 3 Impact Mechanism of the Harvest Period on the Whole-Grain Milled Rice Rate 3.1 Relationship between moisture content and breakage rate during rice milling Many people focus on the milling process, but they overlook an earlier issue. In fact, this problem becomes apparent even during the harvesting stage. The key lies in the moisture content of the grains. When the moisture level is too high, during the subsequent threshing and drying processes, fine cracks are more likely to be left; but if the moisture level is too low, the rice grains become hard and brittle, and they are more likely to break when entering the milling machine. Because both extremes are unsatisfactory, in production, a balance must be found in
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