红壤区施用稻草源生物炭对烟叶钾含量的影响

在红壤区，土壤钾素缺乏严重限制了烟草的需钾能力和品质提升。本研究以稻草源的生物炭为切入点，分别 在水稻土和旱地红壤上设不施钾肥（CK）、化学钾肥（FK）、60%化学钾肥配施 40%的稻草钾肥（60% FK+40% SK）、 60%化学钾肥配施 40%的生物炭钾肥（60% FK+40% BK）等 4 个处理，分析烤烟产量和烟叶钾素含量以及土壤速效钾 含量。结果表明，与 CK 和 FK 相比，60% FK+40% SK 和 60% FK+40% BK 处理可以显著提高烟叶产量和烟叶钾含量， 且水稻土明显高于旱地红壤。在所有处理中，均呈现出 60% FK+40% BK 处理的增幅最高。与 CK 相比，水稻土上 60% FK+40% BK、60% FK+40% SK 和 FK 处理的土壤速效钾含量分别增加了 48.43%、40.88%和 11.95%，旱地红壤上的增 幅分别为 29.63%、22.96%和 20.00%。进一步分析表明，土壤速效钾含量与烟叶钾含量呈显著的正相关关系（p<0.05）。通过拟合方程发现，盆栽试验条件下，水稻土和旱地红壤的速效钾含量增加 10 mg/kg，烟叶钾含量可以增加 0.12%，但还有待进一步验证。因此，在红壤地区，施用稻草源的生物炭可以替代 40%的化学钾肥，且可以保证烟叶产量和提高烟叶钾含量。

Application of Rice Straw-derived Biochar Increasing Potassium Content of Tobacco Leaves in Red Soil

In the red soil area, soil potassium (K) deficiency severely limites the K uptake and quality of tobacco. In this study, one field experiment of straw-derived biochar application was carried out in red upland and paddy soil, which including non K fertilizer (CK), chemical K fertilizer (FK), 60% chemical K with 40% straw K fertilizers (60% FK + 40% SK), and 60% chemical K with 40% biochar K fertilizers (60% FK + 40% BK). The yield of tobacco leaves, K content and the content of soil available K (sodium tetraborate method) were analyzed. 60% FK + 40% SK and 60% FK + 40% BK treatments could significantly increase tobacco yield and the K content of tobacco leaves than CK and FK, and the paddy soil was significantly higher than that of upland soil. Among all treatments, 60% FK + 40% BK treatment was the highest in tobacco yield and K content of tobacco leaves. This was related to the increase of soil available K through biochar and straw. Compared with CK, soil available K content in paddy soil increased by 48.43%, 40.88% and 11.95% on 60% FK + 40% BK, 60% FK + 40% SK and FK, respectively, and it was 29.63% 22.96% and 20.00% in upland soil, respectively. Meanwhile, there was a significant positive correlation between soil available K content and K content of tobacco leaves (p<0.05). The fitted equations showed K content in tobacco leaves could increase by 0.12%, while the soil available K contents increase by 10 mg/kg in paddy and upland red soils. However, the fitted equation would be verified through field experiments. Therefore, the application of straw-derived biochar can replace 40% of chemical K fertilizers, and also guarantee tobacco yield and improve the tobacco K content.