托盘育苗中光温资源差异及其对水稻秧苗素质的影响

托盘育苗是一种露天式立体育苗方式,在不同天气条件下测量并分析其上、中、下3个育苗层的光照强度和温度变化情况,探明其不同育苗层之间光温资源的差异,并以粳稻南粳9108和籼稻Y两优900为供试材料,比较不同育苗层所育秧苗的素质差异。结果表明:各育苗层的光照强度均呈先上升后下降趋势,在午间达到峰值,不同育苗层之间差异显著(P<0.05)。晴天时,3个育苗层的托盘水分温度、根系土壤温度、秧苗间温度均有显著差异(P<0.05),且上层>中层>下层;在同一育苗层,托盘水分温度>根系土壤温度>秧苗间温度;阴天时,中层与下层的温度差异不显著(P>0.05)。从所育秧苗来看(以南粳9108为例),成苗率中层>上层>下层,上层秧苗相较于中层、下层秧苗,株高分别下降19.2%、19.6%,叶龄增大17.6%、29.0%,茎基宽增大14.8%、24.0%,叶片SPAD值、地上部干质量、根数、发根力等性状也显著提高(P<0.05),株高叶龄比K值降低,干物质积累增多,根系生长更好,秧苗整体素质最高;Y两优900表现与南粳9108相似。综上,上层的光温资源最优,所育秧苗也最为健壮;中下层次之,秧苗素质有弱化现象。可适当加大支架间与育苗层间距离,减少育苗层间光温资源差异,提高秧苗素质一致性。

Difference of light and temperature resources in tray seedling and its effect on seedling quality in rice

Tray seedling is a kind of open-air seedling raising method. Under different weather conditions, the light intensity and temperature changes of the upper, middle and lower seedling platforms were measured and analyzed, and the differences of temperature and light resources among different seedling platforms were found out. Nanjing 9108 and indica rice Y Liangyou 900 were used as materials to compare the quality differences of seedlings raised by different seedling platforms. The results showed that light intensity of each seedling platform increased first and then decreased, reaching the peak value in the afternoon, and the difference between different seedling platforms was significant at P<0.05. In sunny days, there were significant differences in tray water temperature, root soil temperature and seedling temperature among the three seedling platforms (P<0.05). In the same seedling platform, tray water temperature>root soil temperature>seedling temperature. In cloudy days, there was no significant difference between the middle platform and the lower platform (P>0.05). In Nanjing 9108, the order of seedling forming rate was as follow: middle platform>upper platform>lower platform. Compared with middle platform and lower platform, the height of upper platform seedlings decreased by 19.2% and 19.6%, respectively, and the leaf age increased by 17.6% and 29.0%, the stem base width increased by 14.8% and 24.0%. Leaf SPAD value, dry weight of upper part of ground, number of roots and rooting ability also increased significantly (P<0.05), the K value decreased, and the dry matter accumulation increased. Y Liangyou 900 showed similarly trend as Nanjing 9108. Therefore, temperature and light resources in the upper platform were the best, and the seedlings were the most robust. Quality of seedlings in the middle and lower platform were obviously weakened. In order to reduce the differences of light and temperature resources and improve the consistency of seedling quality, the distance between scaffolds and seedling platforms could be increased appropriately.