Effects of three organic and inorganic fertilizers combined application on absorption of nitrogen and potassium,yield and quality of watermelon

[Objectives]To investigate the effects of three organic and inorganic fertilizers combined application on absorption of potassium and nitrogen,yield and quality of watermelon,and explore the relationship between nitrogen,potassium nutrition and quality of watermelon.[Methods]‘8424' variety of watermelon was used as materials to carry out field experiment.Three organic and inorganic fertilizers combinations were soybean meal compost,pig manure / straw compost and sheep mature.These combined fertilizers had equal N,P,K content,which were regulated by inorganic fertilizer.[Results]Compared with soybean meal compost fertilizer and pig manure /straw compost fertilizer,application of sheep mature increased watermelon yield by 19.1% and 9.4%,respectively.Compared with pig manure / straw compost fertilizer,application of sheep mature and soybean meal compost significantly improved vitamin C contents by 59.4% and 35.6%,respectively.The ratio of sugar to acid in watermelon of soybean meal compost application was the highest.The soluble sugar content in watermelon was 25.2% higher in soybean meal compost application than that in pig manure / straw compost application.The titratable acid content in watermelon was 30.3% lower in soybean meal compost application than that in sheep mature fertilization.Nitrogen content in melon pulp and rinds in pig manure / straw compost fertilization was lower than that in application of sheep mature and soybean meal compost at expanding period and mature period.The absorption of nitrogen and potassium in sheep mature application was higher than that in other combined fertilizations at young fruit period,expanding period and mature period.The biomass of watermelon was positively correlated with absorption of nitrogen and potassium.[Conclusions]Sheep mature application increased watermelon yield,promoted absorption and translocation of nitrogen to fruit,and increased the titratable acid content in watermelon.Soybean meal compost fertilization improved watermelon soluble sugar content and the ratio of sugar to acid,decreased watermelon titratable acid content.