| Seedling is an important part of vegetable production, which is the foundation to obtain high yield and quality of vegetables. With the increasing demands of vegetables, centralized vegetable seedling in factories has become a mainstream. Seedling substrate choices of conventional vegetables especially the Solanaceous varied with the development of many kinds of new base materials. Vermicompost is the product of earthworm digesting organic solid waste, which has good aeration and drainage properties, high water holding capacity, abundant nutrients and beneficial microorganisms. Accumulated evidence demonstrated that vemicompost had potential to be a high-quality seedling substrates. Based on the availability of local organic waste in Nanjing, the effect of fermentation dregs, tea-leaf compost and vermicompost derived from cattle manure and conventional seedling substrates such as vermiculite and perlite were compared in this studys. Tests of tomato seedling substrates and subsequent pot experiments with the use of microbial agents can not only provide the basis for resource utilization of organic waste, but also provide a theoretical basis and technical guidance for screening special type of Solanaceous seedling substrate which is organic, environmentally friendly, cost-effective.The main results are as follows:1. Seedling substrates which composed of vermicompost and fermentation dregs or tea leaves mixed at different proportions showed high potential as tomato seedling substrates. The effects on seedling performance is significantly better than the conventional substrate(CK) which was commercially available. For example, germination rates in treatments mixted with vermicompost were about 5% higher than that of the CK. Other parameters such as seedling height, stem diameter and hypocotyl length in 2 leaves stage were also significantly higher than CK (p<0.05).2. Compared to the control treatment, the treatment groups with supplentary 20%(volume) vermicompost had optimal effects on the total fresh (dry) weight, root fresh (dry) weight, leaf fresh (dry) weight, growth function and seedling index of tomato seedling.3. With the increasing proportion of vermicompost, the nutrient contents including nitrogen, phosphorus and potassium in seedling substrates decreased, while the contents of organic matter, available phosphorus and available potassium increased. This indicated that the form of nutrients in vermicompost is mainly plant available nutrients, supporting that the suppemented vermicompost in seedling substrates promoted seedling growth.4. The mixture of vermicompost in seedling substrates also affected plant physiological processes of tomato seedlings. For instance, the malondialdehyde (MDA) contents in tomato seedlings grown in substrates with vermicompost were significantly lower than that in CK, indicating vermicompost induced high antioxidant capacity in tomatoes. When the ratio of vermicompost ranged from 0% to 30%, peroxidase activity gradually increased, indicating that vermicompost contributed to improvement of the seedlings lignification process.5. In pot experiments, the amounts of vermicompost and most growth traits of tomatoes were positively correlated. At colonization and florescence stages, plant height, stem diameter, leaf area and chlorophyll content gradually increased with the increasing amounts of vermicompost.The treatment with adding 10%(mass) vermicompost were significantly better than the other treatments, which made tomatoes bloom a week earlier. At the fruit stage, the treatment with higher proportion of vermicompost had certain advantages in terms of fruit shapes and fruit sizes, despite the differences did not reach significant level.6. In the pot experiment, the two types of seedlings compared were those derivated of conventional and vermicompost substrates. The amendment of vermicompost in substrates had significant promotional effects on the subsequent tomato growth. Significant interactions between the seedling origins and soil amended with vermicompost or not revealed vermicompost increased tomato growth at both growth stages.7. Regarding to the plant performance including plant height, stem diameter, SPAD value and the latter part morbidity, the pot experiments showed that amending PGPR (Bacillus subtilis) and antagonistic bacteria (Bacillus amyloliquefaciens) at the stage of breeding and early florescence period didn’t promote tomato growth. On the contrary, the PGPR would inhibite the growth of seedlings, but did promote plant growth if the PGPR amendment being at colonization and florescence stages during the pot experiment. |
