| In modern facility agriculture,seedling substrate is an important material for factory nursery.Grass carbon,as a traditional seedling substrate,has damaged the wetland ecosystem and released a large amount of carbon,which seriously affects the sustainable development of the environment and is not conducive to the implementation of the "double carbon" goal in China.In this study,the combination of coal-based solid waste fly ash and agricultural waste was used as seedling substrate after harmless treatment with vermiculite.Seven treatments were set up,each with three replications,using commercial substrates as control(CK)and mixing 10%(M)and 30%(H)fly ash mixes with vermiculite in proportions(1:1,1:2,1:4,by volume)of M11,M12,M13 and H11,H12,H13,respectively,to investigate the physicochemical properties of the composite substrates and their effects on the growth,development and physiological characteristics of tomato seedlings.The feasibility and suitable ratios of the composite substrates with different ratios of fly ash as tomato seedlings were investigated to provide a basis for the recycling of solid waste resources and the development of soilless substrates in Yulin.The main research results are as follows:(1)Fly ash is feasible to be used for soilless seedling cultivation after treatment.The physical properties such as porosity and weight capacity of the seedling substrate after mixing fly ash substrate with vermiculite in different ratios were in the range of ideal substrates.The total nitrogen content of the treatment group increased by 19.9%～166.90% compared with the control group CK;the fast-acting phosphorus content increased by 2.5%～14.35%compared with CK,and the dissolved alkaline nitrogen content of the treatments M11,M12,H11 and H12 increased by 2.3%～70.39% compared with the control group CK,indicating that the fly ash mixture compounded with vermiculite increased the nutrient content of the seedling substrate and was better than the commercial substrate.(2)By measuring the growth index of tomato seedlings after raising tomato seedlings with different ratios of fly ash substrates,it was found that the seedling emergence rate,plant height,stem thickness and strong seedling index of the substrate containing 30% fly ash were generally better than those of the treatment groups containing 10% fly ash content,with the treatment groups H11,H12,H14 and M14 showing an increase in plant height by 22.3%-8.25%,stem thickness by 27.86%-17.14% and dry weight by 27.86% compared to CK.(3)Physiological characteristics of tomato seedlings(3)The results of physiological characteristics of tomato seedlings showed that plant height and chlorophyll,SOD and POD of seedling substrate were significantly correlated when fly ash was added at 30%,indicating that fly ash substrate affected energy conversion and photosynthesis of seedlings and thus improved seedling growth.The plant height,dry weight and seedling strength index of tomato seedlings were negatively correlated with MDA,indicating that the addition of fly ash substrate improved plant stress tolerance and enhanced the adaptability of tomato seedlings to the environment.The combined growth and physiological characteristics indexes were analyzed by the affiliation function,which showed that the H12 treatment scored the highest,so 30% fly ash compost substrate: vermiculite =1:2 was the best fly ash seedling substrate.(4)Using the fly ash proportioning substrate developed in this experiment to replace grass charcoal for seedlings can save 3000～4500 RMB per mu per year compared with domestic grass charcoal as raw material to produce common seedling substrate formulations.The price per cubic meter for the best ratio H12 treatment was 162 RMB,which significantly reduced the cost of seedlings. |
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