露场叠盘暗化出苗与无纺布覆盖对杂交籼稻成苗特性的影响

为探明露场叠盘暗化出苗（darkened emergence by stacked plates in open space,DE）与无纺布覆盖（seedling mulched with non-woven fabric,NM）协同育秧对机插杂交籼稻成苗特性的影响,该研究于2020—2021年在不同气候条件下以杂交籼稻天优华占为材料,以摆盘出苗（swing-plate emergence,SE）和薄膜覆盖（seedling mulched with film,FM）为对照进行试验,探究DE与NM对出苗微环境与出苗特征以及秧苗素质的影响,并验证其机插适应性。结果表明：1）相对于外界环境,DE提高了出苗微环境的平均温度与平均相对湿度。与SE相比,DE降低了温度与相对湿度变异系数,缩短了种子出苗时间,并大幅提高出苗率与出苗整齐度;较FM,NM改善了秧床微环境,促进秧苗均衡生长;DE+NM有效提高成苗整齐度与成苗率,2 a间成苗整齐度较DE+FM、SE+NM与SE+FM分别增加了7.22～8.91、3.67～5.55和8.29～10.38个百分点（P<0.05）,2 a间成苗率分别提高...

Effects of darkened emergence by stacked plates in open space and seedlings mulched with non-woven fabric on seedling characteristics of indica hybrid rice

Abstract: Seedling-raising technology has been one of the most important measures to treat regional seedling raising during machine transplanting. Among them, an efficient seedling raising has been developed for darkened germination by stacked plates and seedlings mulched with non-woven fabric for the hybrid rice in Sichuan rice areas. The better performance of machine transplanting can be realized for even seedling growth and strong packing root. This study aims to clarify the effect of synergistic seedling raising of darkened emergence by stacked plates in the open area (DE) and seedlings mulched with non-woven fabric (NM) on the seedling characteristics of indica hybrid rice. Tianyouhuazhan (the indica hybrid medium rice variety) was taken as the material in 2020-2021. The mode of swing-plate emergence (SE) and seedling mulched with film (FM) were chosen as the controls. A systematic investigation was made on the microenvironment and emergence characteristics in the emergence stage, seedling quality, and the adaptability of machine transplanting under DE and NM treatments. The results show that: 1) The DE increased the average temperature and average relative humidity of the microenvironment during the emergence stage, compared with the external environment (EE). The DE decreased the coefficient of variation (CV) of temperature and relative humidity, while shortening the time of seed emergence, and greatly improving the emergence rate and emergence uniformity, compared with SE. The NM effectively improved the microenvironment of the seedling bed for the balanced growth of seedlings, compared with FM. Finally, the DE+NM effectively improved the seedling uniformity and seedling rate. The seedling uniformity under DE+NM of two years increased by 7.22-8.91, 3.67-5.55, and 8.29-10.38 percentage points, respectively (P<0.05), and the seedling rate increased by 4.08-8.09, 11.79-14.88 and 20.10-40.02 percentage points, respectively (except for DE+FM in 2021, P<0.05), compared with DE+FM, SE+NM, and SE+FM. 2) The DE significantly increased the seedling density, the total root length, the number of white roots, root superficial area, and root biomass per unit area. The NM significantly increased the root volume per unit area. Finally, the DE+NM significantly increased the root volume, root superficial area, root biomass per unit area, and root coiling force (except for DE+FM in 2020). 3) The DE+NM significantly reduced the rate of missed and hurting seedlings, whereas, there was an increase in the ratio of 3-4 plants per hole, and increased the seedlings per hole, indicating the higher quality of mechanized transplanting. The DE+NM can be expected to strengthen the seedling, particularly for the characteristic of "neat seedlings, strong root and suitable for mechanical transplanting". Therefore, the improved seedling raising performed better with the low cost, extensive resistance, high efficiency, and low carbon. The findings can provide theoretical and technical support for strong seedlings raising and higher yield cultivation of rice mechanized transplanting in Sichuan rice area.