Study On Fly Ash Replace The Peat In Tobacco Seedling Substrate

Floating nursery has become the most important nursery way of tobacco, for its saving space, ease of seedling management, conducive to large-scale production, etc.. However, floating nursery needs lots of peat, and peat is non-renewable resource. Many countries have banned dredging because its over-excavation will destroy the environment. So the current urgent need is to find a substitute that is friendly to environment. This study matched several types of nursery substrates for floating nursery with different materials and fly ash, compared the physiological and biochemical indicators of tobacco seedlings that cultivated by different substrates, and evaluated the nursing effect of these substrates.The objective of this study was to provide theoretical basis for finding substitution matrix. The results were as follows:1. Physical and chemical properties of the matrix with different formulations were significantly different. Used as substrates, fly ash had some shortcomings, such as low porosity, poor water and fertilizer retention, higher pH, etc. Adding humus and plant ash could improve physical and chemical properties of substrate, and the best adding proportion was25%.2. Tobacco seedling grew faster and stronger with improved substrate, which was much better than those with common matrix. It needed only38d from sowing to seedling’s cat ears stage, while it was40d in treatment of common matrix. The fresh and dry weight of seedling’s aboveground part were heavier in improved substrate treatment than those of the common, and fresh and dry weight of underground pan of seedling, girth and height were bigger than those of the common.3. The tobacco seedling had more reasonable physiological and biochemical indexes and better inner qualities. Floating nursery with the substrate added25%plant ash, the seedling’s root activity and chlorophyll content were not significantly differ to those of the common; but contents of total soluble sugar, reducing sugar and soluble protein were significantly higher than those of the common, and the activity of converting enzyme and nitrate reductase were also significantly higher than those of the common. 4. The substrate of75%fly ash with addition of25%plant ash was best for tobacco nursery, which could replace the substrate used in present.