Response of soil physicochemical properties and fruit quality to CL-PAM-Ks in apple orchards in dryland

【Background】 Drought is an important factor restricting China’s agricultural development. Tianshui City of Gansu Province is located in the inland, with a warm temperate semi-humid and semi-arid climate, thin soil layer, unfertile land and lack of irrigation conditions. Natural rainfall is an important source of agricultural irrigation water, but affected by geographical location and climatic conditions, the average annual rainfall is small and uneven. As a result, crops have low utilization efficiency of rainfall. Therefore, it is particularly important to improve crop water use efficiency in arid areas. CLP type super absorbent polymer is a kind of new polymer materials, water absorption and water retention ability is very strong, containing a large number of strong water absorption, high permeability can be induced by association with and through the base mesh structure, absorb hundreds of times to thousands of times more than its weight of water, for a variety of crops, fruit trees, vegetables and so on root directly provide plenty of water, to ensure that the crop growth environment, It has positive significance to improve the water use efficiency of orchard. 【Objective】 The purpose of this paper is to study the effect of CLP type super absorbent polymer on soil physical and chemical properties and fruit quality of apple orchard in dryland. 【Method】 This experiment used crosslinked polyacrylamide (acrylamide-potassium acrylate copolymer, English name is CL-PAM-K, abbreviated as CLP) super absorbent polymer. Set four treatments, respectively were: CK: no super absorbent polymer; T1:150 g/plant; T2:250 g/plant; T3:350 g/plant. Soil water content, soil nutrients, fruit appearance quality and nutritional quality were measured to comprehensively evaluate the effects of each treatment on soil physical and chemical properties and fruit quality. 【Result】 At the bud stage, T1 treatment decreased the soil electrical conductivity by 5.70%, 10.82% and 19.64%, in the 0-20 cm, 20-40 cm and 40-60 cm soil layers, respectively. At fruit ripening stage, T1 treatment increased the soil water content by 7.26% and 39.12% in the 20-40 cm and 40-60 cm soil layers, respectively, while decreasing the pH value by 3.43%, 1.38% and 0.23% in the 0-20 cm, 20-40 cm and 40-60 cm soil layers, respectively. The fruit peel puncture strength increased by 16%. The application of 250 g/plant increased the soil water content and available nitrogen in the 0~20 cm, 20-40 cm and 40-60 cm soil layers at the bud stage, as well as the available potassium in the 0-20 cm and 40-60 cm soil layers at both the bud stage and fruit ripening stage. The application of 350 g/plant increased the available phosphorus in the 0-20 cm, 20-40 cm and 40-60 cm soil layers at both the bud stage and fruit ripening stage. The application of 250 g/plant increased the soluble protein and total phenol content of apple fruits. 【Conclusion】 The application of 350 g/plant was the optimal amount of drought-resistant soil amendment to improve soil physical and chemical properties and enhance fruit quality in dryland apple orchards.