沼液为基础营养液的空心菜水培配方优化研究OA

Biogas slurry is rich in nutrients and bioactive components required for plant growth.Using it for hydroponic cul-tivation of water spinach can achieve both resource utilization and ecological benefits;however,its direct application is lim-ited by high ammonia-nitrogen concentrations and nutritional imbalances.In this study,water spinach(Ipomoea aquatica Forssk.)was grown under two initial ammonia-nitrogen concentrations(100 mg·L-1 and 150 mg·L-1).At each concen-tration,four treatments were set:no addition,addition of micronutrients,addition of medium and micronutrients,and addi-tion of macro-,medium-,and micronutrients.The effects of these treatments on water spinach yield,nutrient uptake,and the physicochemical properties of the hydroponic system were systematically investigated.The results showed that at an ini-tial ammonia-nitrogen concentration of 150 mg·L-1,the treatment with macro-,medium-,and micronutrients(T2-D)a-chieved the highest daily yield of 161 kg·667 m-2 d-1,which was 45.5％higher than that of the no-addition group at the same concentration.The total nitrogen uptake,chemical oxygen demand(COD)removal,and total phosphorus(TP)up-take of T2-D were 967 g·667m-2d-1,930 g·667m-2d-1,and 77 g·667m-2d-1,respectively,all significantly higher than those of the other treatments.Based on a comprehensive consideration of water spinach growth performance,nutrient uptake efficiency,and biogas slurry utilization,the optimized formula was determined as follows:dilute the biogas slurry(with an ammonia-nitrogen concentration of 850 mg·L-1)by a volume ratio of 5～6 times to reach an initial ammonia-ni-trogen concentration of 150 mg·L-1,then add 118.91 g·m-2 of potassium dihydrogen phosphate,340.49 g·m-2 of potas-sium chloride,570.20 g·m-2 of magnesium sulfate heptahydrate,177.49 g·m-2 of calcium chloride,and 0.1 mL·m-2 of micronutrient fertilizer.This formula can provide technical support for the high-value utilization of biogas slurry and the de-velopment of the water spinach hydroponic industry.