秸秆还田对烤烟氮积累、分配及利用的影响

Effects of wheat straw returning soil on N accumulation,distribution and utilization of flue-cured tobacco

在田间试验条件下利用^15N示踪技术，于有机质含量为25．7g·kg-1的黄壤上，研究了烤烟在移栽后5、7、9周小麦秸秆还田对烤烟氮积累、肥料氮积累、肥料氮分配以及氮肥利用率，结果表明，当地常规施肥条件下，烤烟于移栽后13周肥料氮积累达到高峰，氮供应拖后，随烤烟生育期的增加，烟株来自肥料氮比例逐渐减低，烤烟生育前期主要吸收肥料氮，后期以吸收土壤氮为主。秸秆于烤烟移栽后5～9周期间还田后，烟株氮积累、肥料氮积累量和来自肥料氮比例及氮利用率均表现降低，并随秸秆还田时间的推迟，对肥料氮的影响逐渐减少。

The effect of wheat straw on N accumulation and distribution in flue - cured tobacco and ^15N uptake and use efficiency of 15N fertilizer was studied on yellow soil in Gnizhou province, when wheat straw returned soil in 5, 7 and 9 weeks after trans- planting respectively. The results indicated that fertilizer N accumulation reached high level in 13 weeks after transplanting, N ab- sorption time was later than that of the tradition N application. The N uptake in tobacco plant was mainly from N fertilizer in early growth stage and from soil in late growth stage. N accumulation in tobacco plant, 15N accumulation, ratio of N from fertilizer, and 15N use efficiency were decreased when wheat straw returned field during 5 - 9 week after tobacco transplanting, and the effect of wheat straw on 15N absorption also decreased as the time delaying of straw return to field.