Study On The Effect Of Mineral Organic Fertilizer On The Quality Of Three Leafy Vegetables

In order to solve the problems of unstable soil properties and reduced vegetable quality caused by the long-term partial application of chemical fertilizers,and the existing biological organic fertilizers cannot meet the nutritional requirements of the entire growth cycle of vegetables.In this paper,three leafy vegetables,lettuce,pakchoi and water spinach are selected.Seven treatments were set up for field trials,namely: no bio-organic fertilizer(CK),0.15% of the commercially available Chengdu Gailgas bio-organic fertilizer(GF1),and 0.25% of the commercial Chengdu Gailgas bio-organic fertilizer(GF2),0.15% of the commercially available Yunnan Xinqing Bio-organic Fertilizer(QF1),0.25% of the commercially available Yunnan Xinqing Bio-organic Fertilizer(QF2),0.15% self-developed mineral organic fertilizer(AF1),0.25% self-developed mineral organic fertilizer(AF2).By measuring the morphological indicators,nutrients,photosynthetic characteristics,quality and soil physicochemical properties of vegetables after ripening,the effects of self-developed mineral organic fertilizers on the quality of three leafy vegetables and their mechanisms are studied.The result shows:(1)Compared with CK,the mineral organic fertilizer treatment reduced the soil bulk density by 0.14 to 0.20 units,increased the soil water content to 21%,and increased the total soil porosity.The increase range of soil alkali hydrolyzable nitrogen,available phosphorus and available potassium content ranged from 38.89% to 46.30%,148.26% to 186.74% and 37.18% to 43.14%.The soil organic matter content under AF2 treatment reached 14.00 g/kg,which was significantly higher than other fertilization treatments.In different fertilization treatments,only AF2 had a significant increase in soil cation exchange capacity compared with CK,with an increase of47.12%.The soil urease activity under the treatment of high-concentration mineral organic fertilizer was the highest,reaching 19.04 mg·g-1·h-1,which was an increase of136.82% compared with CK,the increase of alkaline phosphatase activity was 82.54%,and the increase of invertase activity was 228 %.Compared with traditional bio-organic fertilizer,the soil microbial content,species diversity,richness and uniformity are higher under the treatment of mineral organic fertilizer.Compared with GF2 and QF2,AF2,soil ACE,Chao and Shannon indexes increase by 30.01% and 8.03 respectively.%,26.87% and 6.57%,10.73% and 5.15%.The number of soil bacteria,actinomycetes and fungi also increased significantly,indicating that mineral organic fertilizers can better improve the soil microbial community structure and promote the growth and quality of vegetables by changing the soil microbial ecological environment of the vegetable rhizosphere.(2)Compared with CK,different fertilization treatments can increase the nutrient content and photosynthetic characteristics of leaves,and the effect of mineral organic fertilizer treatment is particularly significant.Compared with CK,AF2,lettuce,Chinese cabbage and water spinach leaf nitrogen content increased by 83.45%,69.38%and 122.06%;phosphorus content increased by 91.18%,86.96% and 115.63%;potassium content increased by 129.17%,44.06%,72.68 %.The transpiration rate and net photosynthetic rate have been greatly improved with the increase of total chlorophyll.Compared with GF1 and QF1,AF1 has 89.85% and 11.23%,54.11% and40.16% for lettuce,pakchoi and water spinach.79.72% and 34.95%,mineral organic fertilizers can promote the opening of leaf stomata and enhance the photosynthesis and metabolism of vegetables.(3)Mineral organic fertilizer can significantly increase the plant height,fresh weight,dry weight and resistance to diseases and insect pests of the three leafy vegetables,and AF2 has the best effect.The plant heights of lettuce,pakchoi and water spinach under AF2 treatment reached 21.10 cm,24.82 cm and 30.63 cm,and the average fresh weight was 112.84 g,22.40 g and 28.52 g respectively.Compared with traditional bio-organic fertilizer,The fresh weight increase range of pakchoi and water spinach was 8.61% ～ 25.01%,13.43% ～ 31.30%,22.14% ～132.25%.Compared with CK,AF2 showed a decrease of 67.19%,81.25% and 75.64% of leaf diseases and insect pests respectively.After 6 months of slow-release period,the vegetables grew well under the mineral organic fertilizer treatment,and the leaves under the other fertilization treatments showed obvious symptoms of nutrient deficiency,indicating that the mineral organic fertilizer can promote the growth of vegetables,and the fertilizer effect lasts more than 180 days,which can provide long-term stable nutrient supply.(4)Mineral organic fertilizer significantly improves the positive quality of the three leafy vegetables and reduces the anti-nutritional quality content.Compared with CK,mineral organic fertilizer has the largest increase in the content of free amino acids and total phenols in lettuce,the largest increase in soluble protein and total flavonoids in Chinese cabbage,and the largest increase in soluble sugar and vitamin C in water spinach.Compared with traditional biological organic fertilizer,mineral organic fertilizer also improves the overall nutritional quality and safety of vegetables.The nitrate content of the three-leaf vegetables under AF2 treatment was lower.The nitrate content of lettuce,pakchoi and water spinach leaves were 191 mg/kg,215 mg/kg and103 mg/kg,which were far below the vegetable safety standard limit.Under the same fertilizer treatment,the nutrient quality content of high-concentration vegetables is higher than that of low-concentration vegetables.In summary,mineral organic fertilizer has a better effect on the overall improvement of vegetable quality than traditional bio-organic fertilizer.After applying mineral organic fertilizers,soil fertility is comprehensively improved,vegetables are growing well and vitality,and nutrient content increases,which in turn greatly promotes vegetable quality and is worthy of popularization and application.