Research On Floating Cultivation Techniques Of Leafy Vegetables

With the rapid development of industrialization and urbanization in China,more and more cultivated land is occupied,and the area of agricultural land is gradually decreasing.At the same time,China is rich in water resources,there are a large number of rivers,lakes and other water resources waiting for development and utilization.However,there are still many technical problems.In view of the above problems,this paper adopts the floating cultivation mode to study the utilization mode and effect of water resources,so as to provide a theoretical basis for the utilization of water resources.Firstly,we screened the floatation cultivation method of liquid surface.Foamed bare root hydroponics（S1）,foamed substrate culture（S2）and floating plate nutrition bowl culture（S3）were used for floating cultivation of leafy vegetables.The results showed that the water spinach and lettuce could not grow normally under bare root culture.The growth and quality of Ipomoea spinach and lettuce under foam substrate cultivation（S2）and floating plate nutrient bowl substrate cultivation（S3）were significantly better than those of S1 treatment.After harvest,the fresh weight of Ipomoea spinach and raw menu plants were significantly better than that of floating plate nutrition bowl culture（S3）.The results showed that foamed substrate culture（S2）was more suitable for floating cultivation of leafy vegetables on S2 level.On this basis,the substrate cultivation method of foam board was optimized,and the matrix formula suitable for floating cultivation of lettuce was studied.Peat,perlite and organic manure（sheep manure）were mixed proportionally.The results showed that when the ratio of peat,perlite and sheep dung was 4:1:1,the growth of lettuce was the best and the yield of single plant was the highest.At the same time,compared with other treatments,we could see that the fresh weight above the ground and the fresh weight below the ground respectively increased by about 20%.The root vitality was the highest,which was significantly increased by 23.71% and 42.17% compared with other treatments.Under these circumstances,the contents of chlorophyll,nitrate and soluble protein were increased by 20%,20% and 15% compared with other treatments,and the content of chlorophyll,nitrate and soluble protein increased by 20%,20%,15%,and the absorption of N,P,Ca and Mg in lettuce increased significantly.In the process of floating substrate cultivation,it was still found that vegetables were undernourished.Next,we started the foliar topdressing experiment,experimenting with different foliar spraying time and frequency,and studying the effect of foliar spraying on the growth of lettuce in the fish-vegetable symbiosis system and the water quality of the system.The results showed that: in the fish vegetable symbiosis system,foliar spraying of nutrient solution provided nutrients to the plant,the absorption of nitrogen,phosphorus,potassium,magnesium and other nutrients increased significantly,the chlorophyll content increased by 25⁴0%,and the plant height increased.Spraying nutrient solution twice in the morning and evening increased the yield of lettuce by 25%,and the contents of soluble solids,Vc and soluble protein increased by about 20% compared with other treatments.At the same time,there was no significant difference in the contents of NH₄⁺-N,NO₂^--N,NO₃^--N and total P in the water,and there was no difference in the quality of fish between the treatments.Considering the difference of water environment,the effects of foliar spraying fertilizer on the growth,quality and nutrient uptake of lettuce in different water environment were also studied.The results showed that the lettuce could not grow normally when the density of fish group was high（Y2）;when the density of fish group was low（Y1）,foliar spraying fertilizer provided nutrients for the plant,the nutrient uptake of nitrogen,phosphorus,calcium and magnesium in the aboveground and underground parts of lettuce increased significantly,the plant height and the number of leaves increased,the fresh weight of single plant was twice that of CK treatment,and the content of chlorophyll and soluble solid increased by about 50%compared with CK treatment.The conclusion is that when the water resources are used,both liquid surface substrate cultivation and foliage spraying have better performance.（1）When the liquid floatation culture is carried out,the foamed substrate can be selected for cultivation.The matrix formula is that the ratio of peat,perlite and sheep dung is 4:1:1,which not only to meet the needs of lettuce growth,but also to be eco-friendly.（2）In view of the lack of elements in the fish-vegetable symbiosis system,foliar spraying is an effective measure,which can not only ensure the growth of leafy vegetables,but also facilitate the purification of fish ponds.Tests have confirmed that spraying two nutrient solutions in the morning and evening can effectively increase the yield of lettuce.When large-scale promotion is carried out,the density of the fish school can be appropriately reduced to achieve the effect of increasing production and improving quality.