李帅 贾龙 赵婷婷 高兴兰 崔德杰 柳新伟

摘 要：为研究翻耕时间对绿肥还田后分解和养分释放规律的影响，利用网袋法在烟田进行冬牧70分解试验。设置2个翻耕时期，分别于2016年3月23日（T1）和4月23日（T2）将绿肥还田，在翻耕后12、25、36、49和61 d取样测定其分解剩余率、氮、磷、钾、碳含量及其累积系数等。结果表明，翻耕期影响绿肥分解速率和养分释放速率，翻耕晚分解速度慢，分解剩余率高，养分释放慢。至试验结束，T1、T2处理绿肥分解剩余率分别为10.98%、25.33%;而全氮、全磷和全钾含量分别为0.76%、1.35%，1.52%、1.42%，0.44%、0.33%;除T2处理的氮素累积系数呈现先增加后减少的趋势外，其他元素的累积系数都呈现降低趋势，至61 d时，T1、T2处理的氮累积系数分别为0.02、0.53;磷累积系数分别为0.13、0.28;钾累积系数分别为0.02、0.03;碳累积系数分别为0.07、0.21，且T2处理各养分累积系数始终高于T1。以上表明T1处理下绿肥各元素释放比例大，分解程度高。

关键词：冬牧70;翻耕期;分解速率;养分动态

Abstract： In order to study the effects of tillage time on decomposition and nutrient release of Dongmu 70， the mesh bag method was used in tobacco fields with two treatments of tillage time. The green manure was returned to the fields on March 23， 2016 （T1） and April 23， 2016 （T2）， respectively. The samples were collected after 12， 25， 36， 49 and 61 d. The residual decomposition rate， N， P， K， C contents and their accumulation coefficients of Dongmu70 were investigated. The results showed that tillage time affected the residual decomposition rate of Dongmu70 with the slower decomposition rate of T2 and the higher decomposition rate of T1. In the end of the experiment， the residual decomposition rates of T1 and T2 treatments were 10.98% and 25.33%， respectively， For T1 and T2 treatments， the total contents of nitrogen， phosphorus and potassium were 0.76% and 2.87%， 1.52% and 1.42%， 0.44% and 0.33%， respectively. The accumulation coefficient of nitrogen for T2 treatment increased from 0 d to 12 d and reduced after 12 d. The others accumulation coefficients were continuously reduced. After 61 d the nitrogen， phosphorus， potassium and carbon accumulation coefficients of the two treatments were 0.02 and 0.53， 0.13 and 0.28， 0.02 and 0.03， 0.07 and 0.21， respectively. The test results showed that for T1 treatment green manure is easy to decompose， easy to release nutrients.

Keywords： Dongmu 70; tilling time; decomposition rate; nutrient dynamics

煙草种植中，由于长期大量施用化肥而忽略有机肥的施用，导致土壤板结、肥力下降，烟草对养分的吸收和利用率降低、品质下降[1]。近年来，针对这种现象，烟区探索种植绿肥并适时翻耕还田，以改良土壤理化性质，提高土壤养分含量，促进作物生长，提高烤烟产量和质量[2-4]。在实际推广应用中，需要考虑两个因素，一是绿肥生物量，二是翻耕后绿肥的分解速度。生物量越高，干物质量越大，生物固碳等生态效应更显著;但是随着绿肥生物量增加，植株体内C/N、纤维素、木质素含量等相应增加，不易分解。……