| In order to solve the problems of nitrogen loss and utilization rate of tobacco planting soil due to excessive application of fertilizer nitrogen,the effects of biochar and fertilizer application on nitrogen,biological characteristics and nitrogen utilization rate of flue-cured tobacco were investigated through field and pot experiment.The research results show that:1 Effects of biochar and nitrogen fertilizer application on nitrogen in tobaccoplanting soilField test results showed that 2 years of continuous biochar fertilizer application nitrogen,improve the soil nitrate nitrogen content and soil particle adsorption capacity of ammonium nitrogen,in the tobacco plant after hitting the top significantly reduce the soil available nitrogen content,in line with the tobacco plant nitrogen absorption law.The results of pot experiment show that the biochar can promote the mineralization and release of ammonium nitrogen in soil,and reduce the leaching loss of nitrate nitrogen.The content of available nitrogen was increased by adding biochar,in which the nitrogen content of 15% nitrogen fertilizer and biochar was higher than that of conventional fertilization.2 Effects of biochar and nitrogen fertilizer application on the biological characteristics of tobacco-planting soil(1)Effects of biochar and fertilizer nitrogen application on enzyme activity and microbial biomass in tobacco-planting soilThe results of field experiment showed that reducing the amount of nitrogen fertilizer significantly increased the soil urease activity and had positive effect on sucrose enzyme.The results of pot experiment showed that the content of microbial biomass nitrogen was the highest in the long term,and in the long term,the biomass nitrogen was reduced by 15% fertilizer and nitrogen,the content of microbial biomass was higher than that of conventional fertilization and 30% fertilizer nitrogen,while in fluecured tobacco flourishing,it decreased by 30% The content of soil microbial biomass carbon was significantly improved by fertilizer nitrogen and biological carbon.(2)Effects of biochar and fertilizer nitrogen application on microbial functional diversity in tobacco-planting soilThe results of pot experiment showed that the value of AWCD increased with the prolonging of culture time,and the AWCD value of flue-cured tobacco grew up,and the maximum was achieved at maturity of flue-cured tobacco,and the AWCD value of 30% fertilizer nitrogen and biological carbon kept high.The principal component analysis showed that the cumulative contribution rate of variance of PC1 and PC2 was 74.89% in rosette stage,fast growing period was 61.42% and mature period was 67.34%.In the period of the cluster,the factors that affect microbial functional diversity are bio-carbon and nitrogen fertilizer dosage,in the long run,the application of biochar has a certain buffering effect,the mainly effect on microbial functional diversity is fertilizer nitrogen dosage,but in the mature stage,T1 and T2 in a quadrant,the influence of microorganism mainly comes from the dosage of nitrogen fertilizer.3 Effects of bio-carbon and nitrogen fertilizer application on root growth of fluecured tobacco(1)Effects of biochar and nitrogen fertilizer application on root physiology of fluecured tobaccoThe results of pot experiment showed that the cross section area of second level root of flue-cured tobacco was increased by adding biochar,and the cross-sectional area of root and level three root and adventitious root were decreased.In fast growing period,the cross-section area of root system and diameter of catheter decreased with the decrease of nitrogen dosage,at the mature stage,the root cross-section area of 15% fertilizer and nitrogen was reduced and the diameter of the tube was the smallest after the conventional application of fertilizer and biochar was applied.In the area of cortex,the proportion of adventitious roots decreased with the decrease of nitrogen application.(2)Relationship between root physiology and root mineral elements of flue-cured tobacco after application of biochar and fertilizer nitrogenCorrelation analysis of root physiological growth and root mineral elements of fluecured tobacco showed that there was no significant correlation between root canal diameter and root mineral element,and the cortex thickness of flue-cured tobacco root had significant positive correlation with Cu and Zn,and the cross-section area of root of three was significantly correlated with Fe.The cortex thickness and Jambi of fluecured tobacco root were negatively correlated with Mn,and cortical thickness and ratio were significantly positive correlations with Na.4 Effects of biochar and nitrogen fertilizer application on the biomass and quality of flue-cured tobacco(1)Effects of biochar and nitrogen fertilizer application on dry matter accumulation of flue-cured tobaccoThe results of field experiment show that the dry matter accumulation of tobacco leaf conforms to the logistic growth model.The time of the maximum accumulation rate of the tobacco plant was shifted forward when the biochar was added.The results of pot experiment showed that in the growth period of flue-cured tobacco,the photosynthetic rate was first increased and then decreased,and after the addition of biochar,the decrease of fertilizer dosage decreased the effect on dry matter accumulation of tobacco leaves,and the dry matter accumulation of flue-cured tobacco was reduced by 15% fertilizer and nitrogen.(2)Effect of biochar and fertilizer application on nitrogen accumulation in flue-cured tobaccoThe field test results showed that 2 years of continuous addition of biochar 2.4 t/hm2 increased the soil nitrogen retention capacity and the nitrogen utilization rate of fluecured tobacco,in the sane time,reduced the dosage of nitrogen fertilizer.Increasing the application of biochar can significantly improve the nitrogen utilization rate of fluecured tobacco,nitrogen utilization rate in field experiment between 34.32%~49.14%,and under the condition of increasing biochar,normal nitrogen application and nitrogen reduction 15% can significantly improve the nitrogen utilization rate of flue-cured tobacco.The results of pot experiment showed that the longest linear accumulation of nitrogen in the leaves of 15% fertilizer and nitrogen was the highest,and the nitrogen utilization rate of flue-cured tobacco was up to 42.83%.(3)Effect of biochar and nitrogen fertilizer application on the quality of cured tobacco leavesThe results showed that the use of bio-carbon could improve the coordination of sugar ratio and the ratio of sugar to nicotine,and increase the ratio of potassium to chlorine in tobacco leaf,and improve the burning of tobacco.The increased application of biochar increased the chlorine content of tobacco leaves and increased the highest potassium content.To sum up,biochar and fertilizer nitrogen(reduce 15% fertilizer nitrogen)reasonable matching application,improve soil inorganic nitrogen content,reduce nitrogen leaching,and improve soil enzyme activity and microbial functional diversity.It promoted the growth and storage capacity of flue-cured tobacco roots,promoted nitrogen uptake and accumulation of tobacco,improved nitrogen utilization rate and improved tobacco quality. |
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