Effects of Flooding Stress on Growth and Yield of Double Cropping Rice in Poyang Lake Plain under Different Sediment Contents

To investigate the effects of flooding stress on the growth and yield of double cropping rice under different sediment contents during the flood period in the Poyang Lake Plain area, a combination of field experiments and indoor analysis was used. Two types of flooding depths, including 2 / 3 plant height and full flooding, and three sediment contents, S1 (0 kg / m3 ), S2 (0. 5 kg / m3 ), and S3 (1. 0 kg / m3 ), were set up. The growth indicators and rice yield of early and middle rice were observed and studied 6 d and 9 d after flooding. The results showed that moderate flooding stimulated rice elongation, continuous internode differentiation, and increased the leaf elongation and width. The height and internode length of flooded plants were increased by 9. 35% and 12. 75% during the heading-flowering stage of early rice, and the leaf area under 2 / 3 flooding was increased by 11. 00% . However, excessive stress inhibited rice growth. The plant height and tiller number of middle rice were decreased by 33. 49% and 29. 28%, and the leaf area was decreased by 30. 94% . At this time, it was difficult for middle rice to extend beyond the water surface, leading to severe sand deposition on functional leaves. The increase in sediment content further inhibited rice growth. Flooding resulted in an average reduction of 32. 35% and 58. 72% in dry matter weight of early and middle rice panicles (P <0. 05). The decrease in seed setting rate and thousand grain weight was the main reason for the decrease in yield of early rice after being flooded during the heading-flowering stage, and the influence of sediment content and flooding time was not significant at this time. Under full submergence of sediment, the yield reduction of medium rice was intensified. The yield reduction rate under S2 and S3 was significantly increased by 31. 63% and 52. 20% compared with that under S1 (P <0. 05). At this time, the yield decrease was the result of the comprehensive effect of spike length, effective panicle number, grain number per panicle, seed setting rate, and thousand grain weight. The research results can provide theoretical and technical support for flood disaster management and food security guarantee in the Poyang Lake Plain area. © 2024 Chinese Society of Agricultural Machinery. All rights reserved.