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采用大田15N同位素示踪试验,在湖北襄樊2个不同海拔的植烟生态区,研究了3个不同烟苗移栽期及施用氮肥对烤烟产量、产值和氮素吸收、利用及分配的影响。结果表明,低海拔和高海拔植烟生态区施用氮肥烤烟产量分别增加29%和19.2%,产值分别增加24.8%和25.7%。与5月5日移栽相比,推迟移栽期(5月15日或25日)对低海拔地区烤烟产量产值影响不明显,但显著提高高海拔地区烤烟产量产值10%~30%。对烤烟总氮累积量的分析表明,推迟移栽期,低海拔地区植株吸氮量增加25%~45%,而高海拔地区植物吸氮量下降6%~20%。低海拔和高海拔试验点烤烟的地上部氮肥利用率分别约为30%和21%。推迟移栽期显著提高生育前期氮肥利用率,但在中后期无明显影响。与总氮积累趋势相反,推迟移栽期,烤烟各部位肥料氮占总氮的比例,低海拔地区下降10%~40%,而高海拔地区增加15%~50%。在高海拔地区,5月中下旬移栽烟苗有利于肥料氮素的吸收利用和增产增收作用。
Using field 15N isotope tracer test, the effects of transplanting and application of nitrogen fertilizer on yield, yield and nitrogen uptake, utilization and distribution of flue-cured tobacco were studied in two different tobacco planting ecological zones in Xiangfan, Hubei Province. The results showed that the yield of flue-cured tobacco with N fertilizer increased by 29% and 19.2% respectively in the low altitude and high altitude tobacco ecological zones, the output value increased by 24.8% and 25.7% respectively. Compared with transplanting on May 5, delayed transplanting (May 15 or 25) had no obvious effect on the yield of flue-cured tobacco at low altitude, but significantly increased the output of flue-cured tobacco at high altitude by 10% to 30%. Analysis of total nitrogen accumulation in flue-cured tobacco showed that nitrogen uptake by plants at low altitudes increased by 25% -45% at late transplanting stage, and by 6% -20% at high altitude. The aboveground nitrogen utilization efficiency of flue-cured tobacco at low altitudes and altitude was about 30% and 21%, respectively. Postponing the transplanting period significantly increased nitrogen utilization efficiency in early growth period, but no significant effect in the late period. Contrary to the trend of total nitrogen accumulation, the ratio of fertilizer nitrogen to total nitrogen in various parts of tobacco decreased by 10% -40% at post-transplantation stage and by 15% -50% at high altitude. In high altitude areas, transplanting tobacco seedlings in late May is conducive to the absorption and utilization of fertilizer nitrogen and increase income.