Effects of super absorbent polymer on growth and yield of cotton under different irrigation conditions in Xinjiang Uyghur Autonomous Region

With the purpose of promoting water-saving irrigation and cotton yield in Xinjiang Uyghur Autonomous Region, the effect of super absorbent polymer (SAP) on the growth, dry matter accumulation and distribution, water absorption and yield of cotton were studied through field experiments. The results showed that SAP application induced to the reduction in plant height, leaf number of the main stem, square number and leaf area, while an increase in boll numbers. SAP application could accelerate the growth of root, square and boll. The dry matter allocation ratio from nutritional organs to reproductive organs increased by 13.8%–25.8%, and the water transportation ability from roots to stems and leaves was also enhanced. Compared to the usual irrigation quantity of farmers, SAP application could save water 21.1% and increase yield 6.7%–22.0% under proper water-saving irrigation (the irrigation quantity was above 40% of the usual irrigation quantity). When the irrigation quantity was 40% of the usual irrigation quantity, the yields of cotton were not reduced with SAP application. Moreover, the yields could increase 22.0% with SAP application and 7.4% without SAP application, compared to the control (usual irrigation, without SAP application), when the irrigation quantity was about 80% of the usual irrigation quantity, which was considered as the optimal irrigation quantity. The high production of cotton was relative to the increased boll numbers and boll weights, and the regulation of dry matter accumulation, distribution and water metabolism with SAP application.