| Protected horticulture such as soilless cultivation is an essential part of sustainable agriculture in the world.Along with adjusting the agricultural structure recently,protected horticulture facilities has been rapidly developed nationally.Currently,the soil cultivation is still the main cultivation mode,while soilless cultivation under developing.Thus,to explore the effects of different cultivation methods and optimization of process management on the yield and qualities of vegetables would be theoretically significant for developing the facilities vegetables in China.This research studied the influences of different cultivation methods,i.c.soil cultivation and soilless cultivation(substrate cultivation and hydroponics),on the growth and qualities of leaf vegetables(lettuce,Chinese cabbage,spinach,and celery).The data were analyzed by membership function method.Studies on process management of water and fertilizers and regulating of nitrate was investigated.The main conclusions are as follows.(1)There was significant difference in yield of four leafy green vegetables cultivated by different cultivation methods,with a similar trend on output.Those produced via substrate cultivation had the highest yield,while those from soil cultivation had the lowest production.Compared with the soil cultivation,substrate cultivation could achieve more vegetable yield,with the increase of 37.39%,155.76%,182.90%,and 82.13% for lettuce,Chinese cabbage,spinach,and celery,respectively.Celery produced in the hydroponics had more yield of 95.36% and 255.81% than those cultivated in the substrate and the soil,respectively.(2)Different cultivation methods also affected the quality of leafy greens,with relations to the varieties of vegetables.Lettuce,green cabbages and spinach produced from substrate cultivation showed best overall quality,while celery had the best overall quality in soil cultivation.Nitrate contents of four green leafy vegetables werehighest in hydroponics,while lowest in soil cultivation.The continuous cropping could accumulate the nitrate in vegetable.(3)A set of substrate matrix for spinach was screened as a mixture of peat:perlite: vermiculite(1:1.2:1.2)and rotten cow muck at a ratio of 5:1.In this formula,spinach had the highest yield and best overall quality.(4)A process management of celery and lettuce was optimized on fertilization.The addition of nutrients at late stage significantly increased celery’s yield in both soil cultivation and substrate cultivation.When microbial fertilizer was applied for lettuce by both spraying and irrigating,the nitrate content in the lettuce significantly reduced.Especially,the reducing effect of nitrate was more pronounced when two treatments were combined. |
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