播深和播量对宁夏地区直播稻幼苗素质和产量的影响

为探究播深和播量对宁夏地区直播稻幼苗生长发育和产量的影响，以宁夏水稻主栽品种富源4号为试验材料，采用二因素裂区设计，设置4种播深：1、2、3和4 cm,4个播量：112.5、187.5、262.5和337.5 kg·hm^-2，研究不同播深和播量对直播稻幼苗素质及其产量的影响。结果表明，播深×播量对水稻出苗率的影响存在显著的互作效应，其中播深1～2 cm、播量112.5～187.5 kg·hm^-2四种组合较其他组合的出苗率明显增加；幼苗素质中苗高、茎基宽、充实度和壮秧指数4个指标均在播深2 cm、播量262.5 kg·hm^-2组合中优于其他组合；发根力在播深2～3 cm、播量187.5 kg·hm^-2两种组合中优于其他组合；幼苗整齐度在播深3 cm、播量262.5 kg·hm^-2组合中优于其他组合。在幼苗素质指标中，播深×播量对充实度和壮秧指数的影响均存在极显著的互作效应。对于根系生理指标，根系活力、根系总吸收面积和根系活跃吸收面积在播深2 cm、播量187.5～262.5 kg...

Effects of Sowing Depth and Amount on Rice Seedling Growth and Yield in Ningxia Region

In order to explore effects of sowing depth and amount on seedling growth and yield of direct-seeding rice in Ningxia， the main rice variety Fuyuan No.4 was used as the test material. The two-factor split-plot design was adopted， with four sowing depths of 1， 2， 3 and 4 cm and four sowing rates of 112.5， 187.5， 262.5 and 337.5 kg·hm^-2， to study the effects of different sowing depths and sowing rates on the seedling quality and yield of direct-seeding rice. The results showed that there was a significant interaction effect between sowing depth and sowing rate on the emergence rate of rice， among which the emergence rate of four combinations with sowing depth of 1～2 cm and sowing amount of 112.5～187.5 kg·hm^-2 increased significantly compared with other combinations. In seedling quality， the four indexes of seedling height， stem base width， plumpness and strong seedling index were superior to other combinations coupled with sowing depth of 2 cm and sowing amount of 262.5 kg·hm^-2. The rooting ability of two combinations of sowing depth of 2～3 cm and sowing amount of 187.5 kg·hm^-2 was superior to other combinations， and the uniformity of seedlings was better than others with sowing depth of 3 cm and sowing amount of 262.5 kg·hm^-2. Among the indexes of seedling quality， the effects of sowing depth multipled sowing amount on plumpness and strong seedling index have extremely significant interaction effects. As for root physiological indexes， the root vigor， total absorption area and active absorption area of root system in three combinations with sowing depth of 2 cm， sowing amount of 187.5～262.5 kg·hm^-2， and sowing depth of 3 cm and sowing amount of 187.5 kg·hm^-2 were better than other combinations， and there was a significant interaction effect between sowing depth and sowing amount on the above three indexes. Further， the membership function combined with weight analysis method was used to comprehensively evaluate （D value） 12 seedling quality related indexes under different sowing depth and sowing rate combinations， while four better combinations with sowing depth of 2～3 cm and sowing amount of 187.5～262.5 kg·hm^-2 were selected. The results of yield analysis showed that the two combinations with sowing depth of 3 cm and the sowing amount of 187.5～262.5 kg·hm^-2 increased the yield obviously， and the yield increase rate reached 4.29%～17.10%. To sum up， the suitable combination of sowing depth and sowing rate （sowing depth of 3 cm， sowing amount of 187.5～262.5 kg·hm^-2） can promote the growth of direct-seeding rice seedlings by improving rooting ability， seedling uniformity and root absorption area， and improve the population quality of direct-seeding rice， thus increasing the yield of direct-seeding rice. The results of this study laid a theoretical foundation for the construction of direct seeding cultivation techniques of rice covered with soil in Ningxia.