Effects Of Biochar On Four Kinds Of Soil Physical And Chemical Properties Of Flued-cured Tobacco In Xiangxi Area

The application of biochar can not only alleviate the greenhouse effect caused by carbon dioxide and other greenhouse gas emission, but also can improve the soil physical and chemical properties and biological properties,it has been widely used in soil improvement recent years.In this study, the effects of applying biochar on soil physical and chemical properties were analyzed systematically in the four tobacco growing soils in Xiangxi area.The main results are as follows:(1) The physical and chemical properties of four kinds of soils were improved, but the effects were different due to the soil properties, Red lime soils'improvement effect was the most significant.Among them,the soil pH rose 0.46 units,bulk density decreased by an average of 6.14%,the field water capacity increased by 25.05%.In the soil,the alkaline hydrolysis nitrogen increased by 32%,the available available phosphorus increased by 283%,the available potassium increased by 25%,the catalase activity increased by an average of 56%,,the invertase activity increased by 30%,,the urease activity increased by46%.(2) In terms of physical properties, the soil bulk density decreased and the field water holding capacity increased in four kinds of soils during the growing period of flue-cured tobacco. Among them, the most significant effects were paddy soil and purple soil.(3) In chemical properties, nitrogen and potassium content of four kinds of soil were significantly improved. In addition to purple soil,the phosphorus content, pH value of other three kinds of soils were also increased significantly, the effect was most marked in red lime soil.(4) In the activity of soil enzyme, Biochar had a significant promoting effect on four kinds of soil urease and invertase activity, especially in the root and squaring stage of flue-cured tobacco. The promoting effect of catalase activity on red lime soil, paddy soil, yellow lime soil increased with the growth of flue-cured tobacco,its'effect on the activity of catalase in purple soil was inhibited, but the inhibition effect was gradually decreased with the advance of the growth period.