利用安徽省池州市东至县典型烟田土壤,采用尼龙网袋法研究了烟杆还田后的腐解速率及养分释放规律.结果表明,烟杆还田后,腐解速率表现为前期快、后期慢.试验期间(120 d),常规还田、添加白云石粉和生石灰还田烟杆的累计腐解率分别为56%、53%和49%.各处理烟杆还田的养分释放率均为钾>磷>氮.烟杆还田前15 d内,钾的释放达到88%,磷的释放率为76%,而氮的释放率仅为53%.烟杆还田对土壤pH有显著影响,在整个腐解过程中生石灰和白云石粉处理土壤pH均显著高于常规还田和不还田处理.烟杆还田显著增加土壤速效钾的含量,较不还田提高47%.由烟杆腐解特点和养分释放的规律可见,烟杆中的钾是水浸提的速效钾,水稻推荐施肥量中可考虑减去(或部分减去)所用烟杆的钾含量.%Decomposition rates and nutrient release patterns of tobacco straws were studied by nylon-bag experiment. Results showed that the decomposition rate of tobacco straw were fast at the beginning and then slowly decreased with the decomposing process. During the experiment (120 d), the cumulative decomposed rates of tobacco straw were 56%, 53% and 49% for the conventional method, dolomite powder and lime treatment, respectively. The release rates of the nutrients in tobacco straw followed an order of K>P>N in all of the treatments. Within 15 d of the treatment, the release rates of K and P were about 88% and 76%, respectively, however, only about 53% of N was released from tobacco straw. Tobacco straw returning had a significant effect on soil pH. Soil pH values with dolomite powder and lime treatment were significant higher than that of the conventional treatment. Tobacco straw returning significantly increased soil available K content by 47% compared with non-straw returning treatment. Based on the above results, K in tobacco straw was inferred as water extractable and available K, thus, it should be subtracted from the recommended fertilization rate for the rotate rice.
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