Study Of Seedling Raising Substratefor Medium Hybrid Rice Based On Factory Seedling

Rice mechanized transplanting has strict requirements on seedling. The quality of seedling greatly influence planting quality and the growth of rice, ultimately affect rice yield. The ultimate goal of rice seedling substrate is sow the seed, sprinkle with water, and produce healthy seedlings which is suitable for mechanized transplanting, and this seedling raising method is a new type of rice seedling in economic benefit, ecological benefit and social benefit. In this study, the Heng ao da, Jiang yuan and Chai mi he substrate which have good response in market were introduced in 2013, through the comparison of seedling in greenhouse environment, selected a kind of substrates fit for medium hybrid rice mechanized transplanting. In the substrate development test, straw, mushroom dregs, peat, vermiculite and light loam were used as substrate material, surveyed substrate physical and chemical properties and the seedling quality, summarized the substrate material suitable usage and consumption, according to the quality of seedlings forecasted the most excellent seedling substrate. The main results are as follows:1. The 3 substrates showed large differences in the seedling quality and yield. The seeding which used Heng ao da substrate grow fast, and have the advantages in the plant height, stem diameter, leaf area, root development compared with the nutrient soil, but in the aspects of rooting ability of the poor performance is weakness. The growth of rice seeding which used substrates is not easy to control, and seedling age prolonged will reduce transplanting quality and seedling quality.2.Different matrix has different performance in substrate. Mushroom dregs have the characteristics of high P and high pH, so it need to be used with acidic material, the appropriate dosage is 10%-70%. it is conducive to the growth of seedlings. The difficulty of the use of straw lies in compost maturity, different compost maturity performance different in substrate. Depth study on straw decomposition is necessary. Peat have the advantages of high nutrients, low pH, and have the Disadvantage of poor water holding capacity. Peat has a positive effect on rice seeding when it is the main nutrient source, it dosage should not exceed 40% when it is together with mushroom dregs and straw. Vermiculite in the matrix mainly to improve the water retention and chemical property, it has different influence on rice seeding with the use of different material, at a dosage of 10%-30% is fit. From the point of ecological and optimal prediction, the dosage of light loam shoud be low.3. The physical properties of the substrate in the study did not become the limiting factor for rice seedling growth:Bulk density(g/ml) changes in the scope of 0.33-0.69, total porosity changes in the scope of 0.4-0.74, aeration porosity changes in the scope of 0.017-0.16, water holding pore changes in the scope of 0.31-0.66, void ratio changes in the scope of 0.03-0.69. Reducing the bulk density and increasing the void ratio by reduce water retention porosity have a positive role on reducing dead leaf number and root growth. In this study, total N content has a positive effect on seedling growth, available N and organic matter have negative effect on seedling growth. total P content has a positive effect on root growth, available P Has the opposite effect. Through the theory of optimal prediction, the substrate mushroom dregs:vermiculite:light loam=6.6:2.4:1, peat:vermiculite:light loam=6.1(5.5):2.9(3.5):1(1), straw.-vermiculite:peat:light loam=7:1·:1:1, mushroom dregs:vermiculite:peat:light loam=1:1:4.7:3.3, may be suitable, but needs further validation.4. Because of the characteristics of fast seedling, substrate has high economic benefit. Because of the characteristics of reducing tilth soil and utilization of agricultural waste, substrate has high economic benefit. At the same time. substrates showed uneven and unstable physicochemical properties limit the application and popularization. Lowwater retention of Rice seedling substratecause too much water and labor were needed in large scale production, this is another difficulty of promotion. Develop rice seedling substrate according to rice varieties and transplanting requirements, keep good work on straw decomposition to avoide secondary Fermentation, and Invente a kind of seedling bed which is fit for rice seeding substrate are outlet.