不同前作对烤烟土壤健康状况的影响

Effect of Different Preceding Crops on Soil Health of Flue-cured Tobacco

从土壤微生态健康(氮素功能细菌数量、酶活性和有机碳含量)的角度对采自三门峡地区的不同前作烟田土壤进行了分析。结果表明,不同茬口土壤的细菌总量、有机碳含量、蔗糖酶活性、纤维素酶活性趋势相同,均表现为甘薯>油菜>辣椒>玉米>烟草;不同茬口土壤的淀粉酶活性表现为甘薯>玉米>油菜>辣椒>烟草;只有甘薯、辣椒、油菜茬口的土壤有机碳含量达到了优质烟叶生产的要求,玉米、烟草茬口的偏低;对氮素转化细菌数量的分析表明:氨化、硝化、固氮、反硝化细菌数量最多的前作分别为辣椒、甘薯、玉米、烟草。前茬差异在一定程度上影响了氮素转化细菌菌落类群数量的变化趋势,其中,甘薯、油菜、辣椒茬更有利于土壤硝态氮(适合根系吸收的氮素存在形式)转化。整体来看,对于烟田,轮作土壤的健康指标维持在较高水平,有助于保持土壤质量,有效缓解连作障碍。

For the soil samples of tobacco field with different previous crops in Sanmenxia area,the soil micro-ecological health, including the number of nitrogen function bacteria, the enzyme activity and the content of organic carbon,was analyzed. The results showed that the trend of bacteria number,organic carbon content, sucrose enzyme activity and cellulose enzyme activity was same, and the order was sweet potato〉oil-seed rape〉chilli）-corn〉tobacco. The previous crops had the following sequence according to the amylase activity： sweet potato〉corn〉rape〉chilli〉tobacco. As for soil organic carbon content,only sweet potato, chilli and rape reached the requirements of high quality tobacco production while the organic carbon content of corn and tobacco soils was low. The analysis of function bacteria showed that the ammonification bacteria,nitrification bacte- ria, nitrogen-fixing bacteria and denitrifying bacteria of chilli, sweet potato, corn and tobacco were the most. The difference from the stubble,to a certain extent, affected the change trend of nitro- gen transformation bacterial colony group quantity, among them, the sweet potato, rape, chilli stubble more conducive to soil NO;- （suitable for root absorption） transformation. Overall, compared with continuous crops, the soll health indicators of crop rotation remain at a high level, which is helpful to maintain soil quality and can relieve the continuous cropping obstacles effectively in tobacco field.