Study On The Screening Of Organic Ecological Soilless Culture Substrates Formula Of Lettuce

This organic ecological soilless cultivation experiment of lettuce was conducted using six kinds of substrates mixed with agricultural waste such as mushroom residue,coir dust,goose feces and perlite in different volume ratios as cultivation substrates,two control groups CK₁.V?novarbo peat?:V?perlite?=8:2,and CK₂.?red soils?were set up at the same time.The effects of different formula substrates on lettuce were compared by the determination of plant morphology,yield and quality of continuous three-crop lettuce planted.The rules of nutrient release of each formula substrates were analyzed by the determination of mineral elements such as nitrogen,phosphorus,potassium.The Duncan-style repeated-difference method was used to test the significance,and the membership function method of fuzzy mathematics was used for comprehensive evaluation.Results are as follows:?1?The six kinds of organic ecological soilless culture substrates had smaller bulk density,larger porosity,and better physical and chemical properties.The contents of total nitrogen,phosphorus and potassium were relatively high,and the available nitrogen,phosphorus and potassium contents were higher than those of the two control groups.Each formula substrate has sufficient fertility to meet the needs of lettuce growth.?2?The organic ecological soilless culture substrates had certain advantages over pure peat and soil cultivation,and had a good promoting effect on the plant height of lettuce,the dry and fresh quality of the above ground parts,and the growth status of the leaves,among which the T₅ and T₆ formula substrates bases the growing advantage of planting lettuce is particularly evident.?3?The yield per plant of the first crop of lettuce planted on each organic ecological soilless culture substrate was significantly higher than that of the two control groups,with an increase range of 6.62%to 117.46%compared to CK₁,and an increase range of70.56%to 247.88%compared to CK₂.The average yield per plant of continuous three-crop lettuce planted in the formula substrates of each experimental group increased from 85.14%to 208.66%compared with CK₁,and the increase range from CK₂ was 129.44%to282.51%.?4?Organic ecological soilless cultivation of lettuce has certain advantages over the two control groups.The contents of Vc in continuous three-crop lettuce planted with T₄,T₅and T₆ formula substrates was higher than that of the two control groups.The contents of soluble sugar in continuous three-crop lettuce planted with T₅ and T₆ formula substrates was higher than that of the two control groups.The contents of nitrate in continuous three-crop lettuce planted with T₄,T₅ and T₆ formula substrates was lower than that of the two control groups.The contents of nitrite in continuous three-crop lettuce planted with organic ecological soilless culture substrates was far below the national limit standard,but had no significant improvement compared with the two control groups.?5?Comprehensively evaluate the yield,Vc content,soluble sugar content,nitrate content,and nitrite content of the first crop of lettuce,the comprehensive evaluation was performed by the membership function method of fuzzy mathematics to screen T₅ and T₆ as ideal organic ecological soilless culture substrates formula of lettuce.?6?In the continuous three-crop planting process,the contents of total nitrogen,phosphorus and potassium in the formula substrates of each experimental group showed a continuous decrease trend;and the total nitrogen and phosphorus contents were always higher than those in the two control groups.The available nitrogen and phosphorus contents in the formula substrates of each experimental group showed a trend of increasing first and decreasing;the available potassium content in the formula substrates of each experimental group showed a continuous decreasing trend;and the available nitrogen,phosphorus and potassium content of each experimental group were always higher than the two control groups.