Effects of Sowing Density on Yield of Dry Direct Seeding Rice under Potato-rice Rotation System

Purpose To investigate the effects of sowing density on population quality and grain yield of dry direct seeding rice under high fertility conditions.

Methods A field experiment was conducted in high fertility soils under a potato-rice rotation system in Yunnan Province. The super hybrid indica rice variety, F You498, was used, and five sowing densities were tested: row and hole spacing with 30 cm×13 cm (CK), 30 cm×11 cm (D1), 30 cm×15 cm (D2), 30 cm×17 cm (D3), and 30 cm×19 cm (D4). The effects of different densities on seedling emergence quality, tiller dynamics, leaf area index (LAI), dry matter accumulation and transport characteristics, yield and its components were compared.

Results With the decrease of seeding density, the number of effective panicle decreased gradually, the number of single hole tillers increased gradually, and the number of grains per panicle increased significantly, so that the total spikelets were maintained above 4.4×10⁸/hm². The appropriate LAI was maintained with different densities, and with the decrease of seeding density, dry matter accumulation and accumulation rate after full ear increased, and the harvest index was improved, so that the grain yield was maintained at a high level (12.0 t/hm² or more).

Conclusion Under the potato-rice rotation system, reducing the sowing density of dry direct seeding rice to 30 cm×19 cm promotes dry matter accumulation after full heading stage, increases grain number per panicle, and achieves stable high yields, with cost-saving and efficiency-enhancing effects.