皖南沿江平原不同年限烟-稻轮作土壤团聚体组成与烤烟产质量的关系

摘　要 ：为探明烟-稻轮作对烟田土壤团聚体理化性质、团聚体组成及烟叶产量与品质的影响，在安徽省皖南池州和宣城主要植烟区开展实验，研究了皖南沿江平原区典型水稻土在烟-稻轮作下团聚体组成变化与烤烟产量和品质的关系，共调查了皖南池州和宣城植烟区9个植烟田块，植烟年限为单季稻（0年）、烟-稻轮作2、4、9年（池州）和烟-稻轮作1、3、5、8、12年（宣城）。结果表明，池州地区土壤2-5mm团聚体含量呈现先增加后降低的趋势；宣城地区土壤轮作1年时2-5mm团聚体含量显著高于其它轮作年限处理，且此级团聚体所占比例与轮作年限之间显著负相关。综合池州、宣城两地，随着轮作年限的提高，烟草产量降低，但池州地区烟叶随着轮作年限的提高中、上部叶中氯含量呈现下降趋势，上部叶中钾氯比随着轮作年限提高而增加；宣城地区其他年限烟叶中、上部叶中糖碱比均高于1年轮作的烟叶，且轮作5-8年内适合优质烤烟生产（变化稳定）。同时，池州地区上部烟叶刺激性和干燥感评分随着轮作年限的提高呈现下降趋势；宣城地区上部叶香气特性评分随着轮作年限增大而增高。池州和宣城两地土壤2-5mm团聚体含量与烟草产量呈现显著正相关关系，且产量均受2-5mm团聚体pH的影响显著。池州地区土壤每千克土壤中2-5mm级团聚体含量与烟叶中总糖呈现显著正相关关系。通过建立随机森林模型发现，池州地区烟叶中总糖含量受碱解氮含量影响显著。2-5mm团聚体含量与理化性质对皖南烟区烤烟产量和品质有着重要作用，通过施用秸秆、有机肥和土壤改良剂等高效培育土壤团聚体的施肥方式，可以改善土壤团粒结构，提升烟田土壤质量，保障安徽皖南烤烟适产、稳产、优质和风味独特。

Relationship Between Soil Aggregate Composition with Yield and Quality of Flue-cured Tobacco Under Different Rice-tobacco Rotation Years in Yangtse Plain South Anhui

Abstract: In order to investigate the effects of tobacco-rice rotation on the physical and chemical properties of soil aggregates, aggregates composition, tobacco yield and quality of tobacco leaves, experiments were conducted in Chizhou and Xuancheng tobacco growing areas in southern Anhui Province. The relationship between aggregates composition with yield and quality of tobacco in typical paddy soils in plain areas along the Yangtze River in southern Anhui Province was studied. Nine tobacco-growing fields in Chizhou and Xuancheng tobacco-growing areas in southern Anhui Province were investigated, including single cropping rice (0 years), tobacco-rice rotation (2 years), tobacco-rice rotation (4 years), tobacco-rice rotation (9 years) in Chizhou areas; tobacco-rice rotation (1 year), tobacco-rice rotation (3 years), tobacco-rice rotation (5 years), tobacco-rice rotation (8 years), tobacco-rice rotation (9 years) and rotation for 12 years in Xuancheng areas. The results showed that the soil aggregate content of 2-5mm in Chizhou area increased initially and then decreased; the soil aggregate content of 2-5mm in Xuancheng area was significantly higher than that in other rotation years, and the proportion of 2-5mm aggregate in soil was negatively correlated with rotation years. Integrated Chizhou and Xuancheng results, with the increasing of rotation years, tobacco yield has decreased, but the chlorine content was decreased in middle and lower leaves and the K/Cl ratio in lower leaves increased with the increase of rotation years in Chizhou area; the Sugar-alkali ratio in middle and lower leaves of other years in Xuancheng was higher than that in 1-year-rotation treatment. The tobacco rotation years within 5-8 years were suitable for high quality tobacco production (stable). The scores of irritability and dryness of upper leaves in Chizhou areas showed a downward trend with the increase of rotation years, while the scores of aroma characteristics of upper leaves in Xuancheng areas increased with the increase of rotation years.There was a significant positive correlation between 2-5mm soil aggregate content and tobacco yield in Chizhou and Xuancheng areas, and the yield was all significantly affected by the pH of 2-5mm aggregates in these two areas. There was a significant positive correlation between the content of aggregates of 2-5 mm per kilogram of soil and total sugar in tobacco leaves in Chi zhou area. By establishing a random forest model, it was found that the total sugar content of tobacco leaves in Chizhou area was significantly affected by available nitrogen content. The content and physicochemical properties of 2-5mm aggregates play an important role in tobacco yield and quality in southern Anhui. By application of straw, organic fertilizer and soil amendments, we can effectively cultivate soil aggregates, improve soil aggregate structure, improve soil quality in tobacco fields, and ensure the appropriate, stable, high-quality and unique flavor of flue-cured tobacco in southern Anhui.