Effects of different water and nitrogen regulation on the growth and yield of watermelon under mulch drip irrigation in irrigation area

LUO Shuanglong; MA Zhongming; XUE Liang; WANG Zhiqi; TANG Wenxue; LIAN Caiyun

doi:10.16861/j.cnki.zggc.2024.0670

Abstract：To clarify the effects of water-nitrogen synergy on the growth,yield,quality,and water use efficiency of water-melon under film mulching drip irrigation in the Hexi Oasis Irrigation District,and to seek and optimize the optimal water and nitrogen supply for efficient cultivation of watermelon in the irrigation district.A split-plot experimental design was adopted.The main treatments set three soil moisture lower limits(50％,65％,and 80％of the field water-holding capacity of the planned wetted layer soil,respectively),and the sub-treatments set four nitrogen application levels(0,100,200,and 300 kg·hm-2).The effects of different water-nitrogen regulations on the growth,yield,and quality of watermelon under film mulching drip irrigation were studied.The results showed that when the nitrogen application rate was 200 kg·hm-2,it was beneficial to the growth and dry matter accumulation of watermelon,and promoted the formation of watermelon yield and quality.Compared with other nitrogen application levels-the dry matter mass at the mature stage increased by 2.80％-13.30％,and the soluble solid content,yield,and water use efficiency increased by 0.12-0.61 percent point,0.32％-7.57％,and 1.57％-12.43％,respectively.The yield of watermelon increased with the increase of the soil moisture lower limit,increasing significantly by 7.38％-17.97％,compared with the 50％soil moisture lower limit.When the soil moisture lower limit was 65％of the field water-holding capacity and the nitrogen application rate was 200 kg·hm-2,the sugar content and water use efficiency of watermelon were the highest,being 11.00％and 229.05 kg·hm-2·mm-1,respec-tively.Considering the yield,quality,and water use efficiency of watermelon comprehensively,a soil moisture lower limit of 65％of the field water-holding capacity and a nitrogen application rate of 200 kg·hm-2 is the plan for efficient and green production of open-field watermelon in the Hexi Oasis Irrigation District.By determining the soil moisture lower lim-it and nitrogen application range with 85％of the intersection of the maximum values of watermelon yield and soluble sol-id content,the soil moisture lower limit is 72.25％-75.02％,and the nitrogen application range is 204.25-254.15 kg·hm-2.