Effects Of Biochar On Soil Properties And Sorghum Growth Under Different Levels Of Water

Biochar has become a research hotspot as it provides a comprehensive solution for problems such as carbon sequestration and emission reduction, soil improvement, bioenergy production, agricultural waste utilization and so on. In view of the present situation of water shortage in spring and poor soil fertility of Shanxi province, the research try to explore whether biochar can increase soil water availability, improve soil quality and promote crop growth. A experiment by the way of pot in sunlight house and indoor simulation was conducted to evaluate the effect of biochar at application rates of 0(CK), 0.5%,1%,3%,6%(w/w) under three levels of 45%,65%,85% soil relative water content on soil properties and early seeding growth of sorghum (Sorghum bicolor (L.) Moench). The main research content and research results are as follows:1. Effect of biochar on soil physical and chemical properties were studied in this experiment which emphatically analysed the effect of biochar on water characteristics. Biochar application could increase soil water holding capacity and delay evaporation from soil, but soil water availability of plant was decreased. Soil porosity also increased with the rate of biochar application, whereas soil bulk density was declined. With proportion of biochar addition increased, pH, EC and the main content of soil nutrients were also increased in varying degrees. The soil nurtrients of high levels of biochar were immobilized and lost which may be due to higher C/N and pH of the soil after sorghum harvested.2. Effects of biochar on sorghum seeding growth and ntrition adsorption under different levels of water was researched through potted experiment. With water stress mitigated, sorghum growth significantly changed for the better. Better growth status was found at the biochar rates of 0 and 0.5%than in others, along with the high levels of biochar inhibited plant growth. Leaf SPAD values was decline with biochar rate increase, the higher the soil water, the greater the the degree of reduction of SPAD. Water physiological index of crop response to soil available water in 0.5% and 0 biochar treatment were the better. The effect of water on contents of nitrogen phosphorus and potassium of plants was insignificant. With the increase of biochar rate, phosphorus concentrations decreased slightly, potassium concentration increased significantly in aboveground plants. Accumulation of aboveground sorghum nutrient increased significantly with water increased, along with either 0.5% or 0 of biochar treatments accumulation of nutrient was the highest.3. This test analyzed the functional diversity of microbial community of soil after crop harvest and the effect of different treatments on soil enzyme activities. Under the 85% of soil relative water content, the best applicated rates of functional diversity of soil microbial community were 0.5% and 0, the functional diversity of the remaining treatments becomes worse with the biochar increased. Soil moisture could activate soil catalase, invertase and alkaline phosphatase activities, which value increased with a slight increase of water. Along with the increase of biochar, soil urease activity declined; At the rate of 0.5%, the activity of catalase and alkaline phosphatase of soil both were highest; The activity of sucrase increased after its increasing with the bioglass content.4. Comprehensive evaluation of the effection of biochar on soil-plant system by grey relevance analysis method which showed that biochar application rate at 0.5% was the best treatment for soil-plant system under the conditions of water stress. Low application of biochar can moderately optimized soil environment, there was an adverse impact at high levels of biochar (≥1%). The best treatment was 0.5% biochar rate under the 85% level of water in all 15 treatment.