播期与密度互作对直播棉产量及农艺性状的影响

The aim of this study is to clarify the optimum density of middle-early maturing varieties in different sowing dates under direct seeded conditions, so as to provide technical support for light and simple cultivation of cotton after rape(wheat). Ganzamian 0906 was used as the test material, and a two-factor split plot design was adopted in 2020—2022, with sowing date as the main plot (three levels), and density as the sub-area(four levels), to study the effects of different sowing dates and density treatments on cotton agronomic characters and yield. The results showed that delaying sowing date would shorten the growth period. In different combinations of sowing date and density, when sown on May 15th with the density of 67 500-97 500 plants·hm-2, the number of bolls per unit area was relatively high. The interaction between sowing date and density had no significant effect on boll weight and lint percentage. The effect of sowing date on cotton fiber quality is uncertain because of the different climate in each year. In the sowing date range of this experiment, Ganzamian 0906 can obtain high yield as long as it is matched with suitable density. Sowing in late April and early May, the density should not exceed 67 500 plants·hm-2; sowing in mid-May, the optimum density is 67 500-97 500 plants·hm-2; sowing in late May, the harvesting density should be at least 82 500 plants·hm-2.