| Abstract: | [Objective] The effects of planting density and Miantaijin treatment on yield and nitrogen, phosphorus and potassium uptake and accumulation in cotton direct-seeded after wheat in the Yangtze River basin were studied in order to clarify the high-yield cultivation techniques under this cropping system. 【Method】 In 2011 and 2012, Guoxinzao 11-1 at the experimental material, and adopted three densities (75 000, 90 000 and 105 000 plants·hm－2) and three Miantaijin doses (0 mL·hm－2, 1 170 mL·hm－2 and 2 340 mL·hm－2). 【Result】 The results showed that the highest yield was 3 551.3～3 687.5 kg·hm－2 under 90 000～105 000 plant·hm－2 density combined with 1 170 mL·hm－2 Miantaijin (seedling stage: 90 mL·hm－2, peak squaring stage: 180 mL·hm－2, peak flowering stage: 360 mL·hm－2, peak boll-setting stage: 540 mL·hm－2). Under these conditions, the highest uptake of nitrogen, phosphorus and potassium was 117.8 kg·hm－2, 77.4 kg·hm－2, 116.4 kg·hm－2, respectively. Among them, nitrogen uptake was the highest in the peak-squaring stage to peak-flowering stage, while the highest phosphorus and potassium uptake were both detected in the peak-flowering to boll-opening stage. The correlation analysis showed that there was a significant linear positive correlation between the yield of direct seeded cotton after wheat and the total absorption and accumulation of nitrogen, phosphorus and potassium, especially during the peak flowering to boll-opening stage. 【Conclusion】 The suitable application dose of Miantaijin under medium and high density could enhance the absorption of nitrogen, phosphorus and potassium in the whole growth period of cotton, especially in the peak flowering to boll-opening stage. and thus result in the high yield of direct-seeded cotton after wheat in the Yangtze River basin. |
