Effects Of Complex Vermicompost Substrate On The Growth Of Carnation Seedlings

As the traditional horticultural substrate of our country, peat is non-renewable which has limited its application in horticulture. China is a large agricultural country and tremendous amount of agricultural waste is produced annually. The traditional waste treatments have low efficiency and usually cause environmental pollution. Therefore, it is urgent to carry out the research on reasonable utilization of agricultural waste.Vermicompost is a by-product of animal manure decomposed by earthworm, compared to the traditional soilless cultivation substrates; it has good physical and chemical properties, and contains a large number of beneficial microorganisms. Non-toxic and odorless, vermicompost is becoming a new ideal substrate for soilless cultivation.The aim of this study was to select the optimum formula of substrates for carnation cultivation. In order to achieve this, the study compared the growth of carnation on different substrates, including vermicompost, peat, and commercial substrates mixed at different ratios. The results are as follows:1, The physical and chemical properties of vermicompost compound Substrates were optimal for plant growth, which was significantly better than the commercial substrates. The treatments with coir contained more phosphorus and potassium, but less nitrogen than the ones with peat. Vermicompost compound Substrate significantly promoted the germination of carnation, with higher germination and seedling rate than the control. In the control germination started earlier but with low germination rate. The quality of seedling was poorer than that treated with vermicompost compound substrate.2, Adding peat increased N content in the complex substrate, and the release of nitrogen became slower, which could provide a long term nitrogen supply for the plants. On the contrary, contents of phosphorus and potassium and their release in peat added complex substrate were lower than those with coir. Therefore, it is necessary to apply phosphorus and potassium fertilizers in the later growth stage when peat containing substrate is used. While extra nitrogen fertilizer is needed when using coir containing substrates because they have low nitrogen content, leading to nitrogen deficiency in the later growth stage. As release rate of phosphorus and potassium from the substrates with coir was relatively high, it would probably cause nutrient shortage in the later growth stage. Therefore, phosphorus and potassium fertilizers should be dressed accordingly in suitable time and at proper dosage.3, Stem diameter and leaf length of carnation were significantly increased when cultivated on coir containing substrates amended with50-60%of vermicompost, but plant height, branch number and leaf number were not affected, t. Adding peat in substrates helped to promote the leaf development instead of coir. Root biomass of carnation seedlings cultivated on substrates with coir was significantly higher than that with peat. The optimum root growth of carnation was observed in the treatments containing vermicompost, coir and mixed minerals at the ratio of70%-10%-20%and60%-10%-30%. The fresh weight of roots increased remarkably when carnation grew in the substrates added with50-60%of vermicompost, including the three treatments with the vermicompost, coir and mixed minerals ration of60%-10%-30%,60%-20%-20%and50%-30%-20%. Highest biomass was obtained when growing carnation in substrate containing60%of vermicompost,10%of coir and30%of mixed minerals, followed by the treatment containing50%of vermicompost,20%of coir and30%of mixed minerals. Substrate amended with50-60%of vermicompost significantly increased biomass and the number of strong seedlings of carnation.4, Peat-containing substrates were rich in available nitrogen while coir-containing substrates were rich in available phosphorus and potassium; therefore, no fertilizer was needed until30days after sowing when fast growth period of carnation was reached. Some dressing according to status of seedling growth should be considered in order to promote the flowering branch differentiation of carnation.5, The recommended formula of complex substrate for carnation was:60%of vermicompost-20%of coir-20%of mixed minerals. This substrate had better effects lower cost than the commercially available substrates. Conclusively, to replace peat with vermicompost in complex horticultural substrates is feasible both technologically and economically.