生物炭对土壤碳组分及烟草生长发育的影响

为探索生物炭对植烟土壤改良和烟草生长发育的影响效果，采用大田试验设置5个处理T0（对照）:0 t/hm2生物炭+0.64 t/hm2氮肥；T1:0.5 t/hm2生物炭+0.64 t/hm2氮肥；T2:1 t/hm2生物炭+0.64 t/hm2氮肥；T3:1.5 t/hm2生物炭+0.64 t/hm2氮肥；T4:2 t/hm2生物炭+0.64 t/hm2氮肥]，分析了生物炭对植烟土壤碳排放、有机碳组分以及烟草生理指标的影响。结果表明:①与T0相比，中低用量（0.5~1.5 t/hm2）的生物炭处理可降低土壤CO₂排放总量；其中T1、T2和T3处理较T0分别降低28.14%、25.25%和8.41%；而高用量（2 t/hm2）生物炭处理则促进了土壤碳排放，T4处理较T0提高8.79%。②生物炭处理可提高土壤总有机碳、微生物生物量碳、可溶性有机碳和易氧化有机碳含量（质量分数）；在移栽后70 d T4处理的土壤总有机碳和微生物生物量碳含量较T0分别提高19.38%和29.38%；土壤微生物生物量碳占总有机碳比例随生物炭的施入而降低，而土壤可溶性有机碳占总有机碳比例随生物炭的施入而升高。③生物炭处理可提高烟草根系活力，改善烟草叶片光合特性，提高烟草干物质积累量；其中T3处理的烟草根系活力较T0提高80.43%。因此，适宜用量的生物炭可降低土壤碳排放量，提高土壤中碳组分含量，改善烟株根系生长发育状况和光合特性，提高烟株干物质积累量。 

Effects of biochar on soil carbon components and tobacco growth and development

To investigate the effects of biochar on the quality improvement of tobacco planting soil and tobacco production, a field experiment with 5 treatments: T0, 0 t/hm2 biochar+0.64 t/hm2 nitrogen fertilizer; T1, 0.5 t/hm2 biochar+0.64 t/hm2 nitrogen fertilizer; T2, 1 t/hm2 biochar+0.64 t/hm2 nitrogen fertilizer; T3, 1.5 t/hm2 biochar+0.64 t/hm2 nitrogen fertilizer; T4, 2 t/hm2 biochar+0.64 t/hm2 nitrogen fertilizer was conducted. The effects of biochar on the carbon emission and organic carbon components of tobacco planting soils and tobacco physiological indexes were analyzed. The results showed that: 1) Compared with treatment T0, treatments T1, T2 and T3 reduced the total soil carbon emission by 28.14%, 25.25% and 8.41% respectively; and treatment T4 raised the total soil carbon emission by 8.79%. 2) The biochar treatments increased the contents (mass fractions) of soil total organic carbon, microbial biomass carbon, soluble organic carbon and easily oxidized organic carbon. On the 70th day after transplanting, the total organic carbon and microbial biomass carbon in soils of treatment T4 were 19.38% and 29.38% higher than those of treatment T0. The proportion of microbial biomass carbon in total organic carbon decreased, while the proportion of soluble organic carbon in total organic carbon increased with the application of biochar. 3) The biochar treatments promoted tobacco root vigor, the photosynthetic characteristics of tobacco leaves and the dry matter accumulation in tobacco plants. Among them, treatment T3 increased tobacco root vigor by 80.43% comparing with treatment T0. Therefore, suitable biochar applications can reduce soil carbon emission, increase contents of different soil carbon components, promote the root growth and development, photosynthetic characteristics and dry matter accumulation of tobacco plants.