高海拔烟区不同施氮量对土壤氮素矿化及烤烟生长发育的影响OA

The research aimed to enhance nitrogen use efficiency in tobacco-growing soils at high altitudes,reduce nitrogen losses,and provide theoretical basis for selecting optimal long-term nitrogen application rates in high-altitude regions.This study employed in situ field incubation experiments in Qiansuo village,Yanyuan county,Liangshan Prefecture to investigate soil nitrogen mineralization patterns under four nitrogen application rates(0,82.5,105,127.5 kg/hm2,marked as CK,T1,T2,T3,respectively).Results indicated that soil mineralization increased prior to the peak growth period and subsequently declined continuously.The maximum mineralization reached a peak of 11.01 mg/kg at 49 d after transplanting.Increased nitrogen application elevated soil inorganic nitrogen content,with the 20-40 cm soil layer exhibiting significantly lower response to fertilization than the 0-20 cm layer.The impact of fertilization on soil inorganic nitrogen was most evident 63 d after transplanting.In the 0-20 cm soil layer,at 77 d post-transplanting,the inorganic nitrogen content in treatments of T1,T2,and T3 increased by 21.97%,18.21%,and 39.31%,respectively,compared to the CK treatment.In the 20-40 cm soil layer,inorganic nitrogen content across treatments showed a trend of first increasing and then decreasing.Treatment T3 reached its peak at 63 d,exhibiting increases of 12.03%,8.10%,and 3.38%,compared to CK,T1,and T2,respectively.As the growth period progressed,nitrogen content in tobacco plant organs gradually decreased.Nitrogen content and accumulation followed the pattern:leaves>stems>roots.Nitrogen accumulation also increased with higher nitrogen application rates.Agronomic traits such as plant height,stem circumference,and number of effective leaves were positively correlated with nitrogen application rates.Increasing nitrogen application could also enhance tobacco economic benefits to some extent.In this trial,the highest yield and value were achieved at a nitrogen application rate of 105 kg/hm2.In summary,analyses of soil mineralization patterns,agronomic traits,nitrogen accumulation,and flue-cured tobacco economic traits indicated that achieving optimal tobacco production could be facilitated by appropriately increasing nitrogen fertilizer to promote growth and development.Under the conditions of this experiment,the T2 treatment nitrogen application rate of 105 kg/hm2 was recommended for achieving optimal and high-quality flue-cured tobacco production in Yanyuan county.