Objective The effects of different seedling water drip frequencies for cotton field of dry sowing and wet emergence in southern Xinjiang were compared when the clay soil water content was 10%～15%, 15%～20% and 20%～25%, and the appropriate seedling water dripping frequency under each soil water content was determined.
Methods Each soil water content divided into three treatments: one time seedling water, two times seedling water and three times seedling water,a wooden box experiment was conducted to explore the effects of different drip frequency on the end breakage seedling rate, stranglehold seedling rate,surface soil compaction degree, seedling rate, plant height, stem diameter, overground dry matter weight per plant, root mass density, root length density,root surface area density, root volume density, root diameter density and soil electrical conductivity,and the fuzzy comprehensive evaluation method based on entropy weight method was used to comprehensively evaluate 12 traits of different drip frequency.
Results Under three soil water content gradients, the seedling rate, plant height, stem diameter, overground dry matter weight per plant, root mass density, root length density, root surface area density and root volume density for different seedling water drip frequencies were presented as three times seedling water > two times seedling water > one time seedling water, but the root diameter density and surface soil compactness were appeared as one time seedling water > two times seedling water > three times seedling water, the soil electrical conductivity showed that the 10 cm soil layer of seed hole was higher than 5 cm the soil layer of seed hole,the 10 cm soil layer of membrane edge was higher than the 5 cm soil layer of membrane edge in the longitudinal direction, and 5 cm soil layer of membrane edge > 5 cm soil layer of seed hole,10 cm soil layer of membrane edge >10 cm soil layer of seed holein in the transverse direction,end breakage seedling rate was 2.5% when the seedlings water were dripped once times, and there was no end breakage seedling when the seedlings water were dripped twice times and three times,stranglehold seedling rate with one time seedling water and two time seedling water were 5%～7.5% and 2.5%, respectively no stranglehold seedling with three time emergence water,the fuzzy comprehensive evaluation based on the entropy weight method showed that the comprehensive characters of dripping three times seedling water were the best under the three soil water contents.
Conclusion Dripping 3 times seedling water of dry sowing and wet emergence in cotton field is appropriate on the clay.
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