Effects Of Biochar On Coastal Saline Soil Physicochemical Properties And Pakchoi Growth

China is extremely rich in land resource of the coastal areas. As one of the important areas for agricultural development, coastal saline soils and beaches are treated as the main arable land resources in the coastal areas. It is incomplete soil development, shallow soil layer, low soil organic matter content and high salt content that seriously affect local agricultural production. Therefore, to improve coastal saline soils is of great practical significance for ecological restoration and reconstruction, stability and development of the local economy.In this study, we first find out that biochar is primary effevtive to saline soil remedation by evaluating the effect of bamboo biochar on soil electricital conductivity, available nutrient and pakchoi biomass. And then different types of biochar(bamboo biochar vs enhanced biochar) in different ways(biochar plus organic fertilizer vs biochar compost) of different dosages(half dosage vs normal dosage) were applied to soils so as to get the best solution for costal saline soil remadition, by study the effects of biochar on soil physical structure, soil chemical properties, soil carbon and nitrogen forms and pakchoi growth.In addition to groundwater, unreasonable irrigation and too much fertilizer are the main factors that resulted in high soil electrical conductivity. In short term, soil electrical conductivity was reduced effectively with bamboo biochar addition. However, soil electrical conductivity was increased significantly by organic fertilizer and enhanced biochar. Both biochar and biochar compost significantly reduced the soil bulk density and pH and increased the moisture content, which improved the physical structure of castal saline soils greatly.Soil nutrients comes from external fertilizer directly for low nutrient content of biochar. The more fertilizer, the higher content of soil carbon and nitrogen. Soil total carbon and organic matter were improved with biochar application, which is helpful for carbon storage. Combining biochar with organic fertilizer could promote the release of available potassium from fertilizers, however, strong phosphorus adsorption in soil and fertilizer existd in the treatments with biochar compost and enhanced biochar. Slow-release effect on nitrogen nutrient was also concluded from biochar compost and enhanced biochar obviously.Changes in soil environment may affect pakchoi growth. With organic fertilizer application, the pakchoi growth potential was improved significantly. Pakchoi chlorophyll content and soluble protein content were not changed too much with the amount of organic fertilizer. Soluble sugar content were increased with the amount of organic fertilizer obviously. Biochar significantly reduced the nitrate nitrogen content of plants, and becomed much higher with the increasing amount of biochar compost. What’s more, enhanced biochar compost made a greater contribution to pakchoi quality than bamboo biaochar compost.Above all, two types of biochar were effective to improving saline soil phychemical properties in the short term. It could make up low nutrient content of biochar to combine with organic fertilizer to improve pakchoi growth. In fact, biochar compost performed better than biochar plus organic fertilizer in saline remadition. Bamboo biochar made a greater contribution to reduce soil electrical conductivity than enhanced biochar. On the contrary, enhanced biochar compost made a greater contribution to improve pakchoi growth than bamboo biochar compost.