Effect Of Vermicompost-Formulated Substrate On The Growth Of Eggplant Seedlings

As a kind of growth substrate in agro-forestry as well as in horticulture, vermicomposts processed commercially from organic wastes and daily rubbish were applied broadly at home and abroad. Having fine physical structure, abundant chemical elements and varieties of microorganisms, vermicomposts can enhance the growth of plant and improve environment as a result of keeping water and inorganic fertilizer from leakage, reducing the occurrence of environment pollution, e.g. eutrophication.Vermicompost-formulated substrate was mixed with wormcasts and different kinds of inorganic substrate supplemented with macro-elements(urea, superphosphate calcium, sulfate potassium, et al.), not only further improving the physical properties of percentage total porosity, percentage air space, but complementing the shortage of intrinsic nutrients, producing more growth effect during cultivating.This paper first determined the physical and chemical characteristics of vermicompost. During seedling experiments, vermicompost and vermicompost substituted with vermiculite were two comparative groups, each being subdivided into many groups through added different levels of inorganic fertilizers, studying the growth parameters and development of eggplants as well as the dynamic characteristics of macro-elements in the seedling substrate.Through these studies above, we can draw some conclusions as follows:(1)Vermicompost had fine physical structure, relatively more micro-porosity, with layer and particle structure, containing large amount of gel-substrate after air drying which contributed to the micro-structure of vermicompost. The intestinal processing of earthworm enriched the micro-flora, significantly increased the number of fungi, bacteria and actinomycetes, increased the activity of catalase, and reduced the activity of urease. The bulk density, total porosity, aeration porosity, air/water is the largest compared to vermiculite, the water porosity, maximum water-holding capacity the minimum. The lump feature of vermicompost and vermiculite were worse than control groups. The water retention characteristics of vermicompost was better than that of comparison matrix and vermiculite. The bulk density, maximum water-holding capacity of vermicompost supplemented with vermiculite increased when the total porosity, aeration porosity decreased, the proportion changing with the percentage of vermiculite. Vermicompost added with low proportion of vermiculite (vermicompost:vermiculite=16-4:1, v/v) had higher water porosity and lumping feature.Vermicompost added large proportion of vermiculite (vermicompost:vermiculite=1:1, v/v) had higher water porosity. The acid buffer feature and alkali buffer feature of the vermicompost were markedly higher than venniculite, the alkali buffer of the vermicompost notably higher than comparison groups, the acid buffer with little difference.(2)During the entire seedling period, vermicompost-formulated substrate without being added vermiculite (NMFV) and vermicompost-formulated substrate added vermiculite (MFV), both supplemented with sound inorganic fertilizers, had significant influence on the development of the eggplant seedings root, better than market substrates(CK), increasing the root parameters of root length, root surfarea, root volume, tips and dry weight. The effect of MFV on the root length, root surfarea and tips were worse than that of NMFV during mediate-period, whereas the effect on the root length, root avgdiam, tips, fresh weight and dry weight during later stage were better than that of NMFV. All treatments of vermicompost contribute to strong seedlings, especially during mediate-period and later stage. MFV supplemented with inorganic fertilizers (NPK) had most significant effect on the development of eggplant seedlings root.(3) During the entire seedling period, vermicompost-formulated substrate without adding vermiculite (NMFV) and vermicompost-formulated substrate added vermiculite (MFV), both supplemented with sound inorganic fertilizers, had significant influence on the development and physiological parameters of the eggplant seedlings, better than market substrates(CK), increasing the parameters of the chlorophyll, leaf expandedness, plant height, stem diameter, leaf number, shoot fresh (dry) weight, total fresh (dry) weight, G value and sound seedling index. The effect of MFV on the leaf expandedness, plant height, stem diameter, leaf number, shoot fresh (dry) weight and total fresh (dry) weight were better than that of NMFV during mid-period, meanwhile the effect on the eaf expandedness, plant height, shoot fresh (dry) weight, total fresh (dry) weight and sound seedling index during later stage were better than that of NMFV. All treatments of vermicompost contribute to sound seedlings, especially during mid-period and later stage. Vermicompost supplemented with urea (from0.5kg·m-3to1.0kg·m-3) fertilizers had better significant effect on the growth and development of eggplant seedlings.(4) During the entire seedling period, the whole change trend of total nitrogen in vermicompost-formulated substrate was T1(initial stage)<T2(middle stage)<T3(later stage); The change tendency of the organic matter and soluble potassium were T1> T2> T3; Total phosphorus and effective phosphorus in substrate decreased during the process of planting; The change trend of effective nitrogen and pH were not obvious. Compared with market substrates (CK), vermicompost-formulated substrate without being added vermiculite (NMFV) and vermicompost-formulated substrate added vermiculite (MFV) had higher amount of total nitrogen, effective nitrogen, total phosphorus, effective phosphorus and organic matter.