双季稻区杂交稻机插秧低播量精密育秧试验

Experiment on precision seedling raising and mechanized transplanting of hybrid rice under low sowing rate in double cropping area

根据杂交稻种植少本稀植的要求，该文以杂交稻天优998和五优308为材料，采用机械化精密田间育秧试验方法，研究了4种秧盘和4个播种量水平对机插杂交稻秧苗成毯效果、秧苗素质和栽插质量的影响。结果表明：钵体毯状秧盘播种量在65 g/盘以上、毯状秧盘在45 g/盘以上、窄行秧盘在36 g/盘以上，应用华南农业大学研制的“水稻田间工厂化育秧精密播种机”进行精密播种，采用常规田间育秧管理育成的秧苗成毯效果能满足机插的要求；不同秧盘类型对秧苗素质的影响存在显著差异，4种不同秧盘育秧方式中，以钵盘培育的秧苗素质最好，整齐性也最好，钵毯秧苗次之，毯状秧苗与窄行秧苗相差不大；不同播种量对秧苗素质的影响较大，不同播种量之间，秧苗素质各项指标的差异都达显著水平，随着播种量的增加秧苗素质明显下降，表现为叶龄减少，苗高变矮，苗茎宽变细，根长变短，百株鲜质量、百株干质量和百株根质量都变轻；而秧盘与播种量的交互作用对秧苗素质的影响不显著；从栽插质量和满足栽插的农艺要求角度看，对杂交稻天优998而言，钵毯和毯状秧盘的最佳播种量范围为65～80 g/盘，窄行秧盘的最佳播种量范围为52～64 g/盘，钵盘的最佳播种量范围为41～50 g/盘。本文的研究结果对解决杂交稻机插秧技术问题具有理论意义和实际应用价值。

According to the agronomic requirements for mechanized transplanting technology for hybrid rice, using Tianyou 998 and Wuyou 308 as test materials, the effects of a seedling tray and sowing rate on entwining effect of seedling roots, seedling quality, and machine-transplanted quality were studied by mechanized precision seedling raising field experiments. The results showed that when the sowing rate of bowl-flat tray nursing seedlings exceeds 65 g/tray, flat tray nursing seedlings exceeds 45 g/tray, and narrow row tray nursing seedlings exceeds 36 g/tray, the entwining effects of seedling roots were suitable for mechanized transplanting by using reliable mechanized precision planting technology, such as the“Field Factory Seedling Precision Sowing Machine for Rice”developed by South China Agricultural University. Variance analysis showed that the effects of seedling tray types on the seedling quality were significant. Among the four seedling raising methods of tray nursing seedling, the seedling quality and the regularity of bowl tray nursing seedlings were the best, bowl-flat tray nursing seedlings took the second place, and flat tray nursing seedlings and narrow row tray nursing seedlings were the worst. Similarly, sowing rates showed significant differences on all seedling quality indicators, especially highly significant differences were showed on plant height, seedling stems width, root length, fresh weight of one hundred plants, dry weight of one hundred plants, root weight of one hundred plants, and height ratio mass. It was concluded that the leaf age, the plant height, the seedling stems width, the root length, the fresh weight of one hundred plants, the dry weight of one hundred plants, the root weight of one hundred plants, and the height ratio mass will decrease with the increase of the sowing rate. The interaction effect on seedling quality between seedling tray and sowing rates was not significant. Considering the quality of mechanized transplanting and the agronomic requirements of hybrid rice, the suitable sowing density for bowl-flat tray nursing seedlings and flat tray nursing seedlings were from 65 g/tray to 80 g/tray, narrow row tray nursing seedlings were from 52 g/tray to 64 g/tray, bowl tray nursing seedlings were from 41 g/tray to 50 g/tray.