Abstract:

By analyzing the effects of different frequencies of drip irrigation on the emergence rate, agronomic shape and root distribution of cotton fields with different soil water contents under loamy soil conditions in southern Xinjiang, the suitable frequency of emergence water for ‘dry sowing and wet emergence’ under loamy soil conditions was explored, which provided theoretical support for ‘one sowing and whole seedling’ of cotton in southern Xinjiang. Taking upland cotton ‘J8031’ as the test material, under the condition of soil moisture content of 10%-15%, 15%-20% and 20%-25%, the seedling emergence water was set up for 1, 2 and 3 times, respectively. With the increase of drip irrigation frequency, the soil compaction decreased, and the soil EC value decreased gradually. The soil EC value of the same soil depth was less than that of the film edge, and the soil EC value of 5 cm soil depth was less than that of 10 cm under the same hole or film edge position. The emergence rate was the highest when the seedling water was dripped twice, and the lowest when the seedling water was dripped once, and the phenomenon of ‘decapitated seedling’ and ‘stuck neck’ appeared. With the increase of water frequency, plant height, stem diameter and aboveground dry matter accumulation showed a gradually increasing trend. The high frequency of seedling water was closely related to root growth and development. The increase of the frequency of seedling water dripping and the water-oriented characteristics of the lateral root system gradually increased the root weight density, root length density, root surface area and root volume, but the root diameter was the smallest when the seedling water was dripped three times. Under loam soil conditions, when the soil water content was 10%-15%, 15%-20%, and 20%-25%, the emergence water for ‘dry sowing and wet emergence’ dripped twice could meet the germination and emergence of cotton seeds, and the agronomic traits and root morphology were better at the seedling stage.

Key words: South Xinjiang, cotton, soil moisture content, dry sowing and wet emergence, emergence water, seedling stage, loam