1. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China; 2. Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100, China; 3. Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Yangling, Shaanxi 712100, China
Abstract:In order to explore the influence of aeration on the sediment sedimentation capacity in the water and fertilizer integrated drip irrigation pipe network, muddy water with a combination of sediment of six particle sizes and three types of fertilizers(potassium sulfate fertilizer, compound fertilizer and urea, mass fraction of 1.0%)was configured. The turbidity of muddy water, the median settling velocity of sediment and the median particle size of settled sediment before and after aeration were measured under three kinds of flow shear strengths(0, 1.38 and 4.67 s-1). The results show that aeration acce-lerates the flocculation and sedimentation of fine sediment in water fertilizer mixture. After aeration of urea water fertilizer mixture, the increase of median settling velocity of sediment is the largest, followed by potassium sulfate fertilizer, and the compound fertilizer is the smallest, which increase by 89.27%, 52.74% and 45.63% respectively compared with non-aeration treatment. The effect of aeration on flocculation and sedimentation of sediment increases with the decrease of particle size of sediment. Aeration significantly promotes the flocculation of sediment with median particle size less than 31 μm(P<0.05), and the particle size of settled sediment increases by 3.22%-21.99% compared with that of non-aerated treatment. Aeration significantly promotes the sedimentation of sediment with median particle size less than 53 μm(P<0.05), and median settling velocity is 23.96%-89.27% higher than that of non-aerated treatment. The greater the flow shear strength, the smaller the effect of aeration on sediment settlement. When the flow shear strength is less than 4.67 s-1, the median settling velocity of aerated treatment is significantly higher than that of non-aerated treatment by 9.38%-89.27%(P<0.05). The interaction of sediment particle size, fertilizer type, flow shear strength and aeration treatment significantly affects the flocculation and sedimentation of muddy cement sand. It is suggested that the irrigation pipe network should be washed regularly during drip irrigation of water fertilizer gas mixture to reduce the sedimentation sediment in the pipe network.
吕畅,董爱红,张二信,赵雪,王彦邦,牛文全,*. 加气对水肥混合液细小泥沙絮凝沉降的影响[J]. 排灌机械工程学报, 2023, 41(11): 1163-1170.
LYU Chang,DONG Aihong,ZHANG Erxin,ZHAO Xue,WANG Yanbang,NIU Wenquan,*. Effect of aeration on flocculation and sedimentation of fine sediment in water fertilizer mixture. Journal of Drainage and Irrigation Machinery Engin, 2023, 41(11): 1163-1170.