减施氮肥下聚天冬氨酸对烤烟生理特性及氮肥去向的影响

Effects of Polyaspartic Acid on Physiological Characteristics and Fate of Nitrogen Fertilizer in Flue-cured Tobacco with Nitrogen Fertilizer Reduction

针对烤烟种植氮素施用量过多、氮肥利用率不理想等问题,以聚天冬氨酸(PASP)为肥料增效剂、我国烤烟主要种植品种“云烟87”和贵州黄壤为供试材料,采用15 N同位素示踪技术,探索了减施氮肥30%情况下PASP施用对烤烟生理特性和氮肥去向的影响,为PASP应用于烤烟生产提供参考。结果表明:减施氮肥和添加PASP均可有效提高烤烟氮肥利用率,前者提高效果在烤烟生育后期尤为明显,后者在前者的基础上可进一步增强提高效果。常规施肥减氮30%条件下,烤烟根系生理和叶片光合特性受到显著影响;在此基础上添加PASP其烤烟根系生理、叶片生理形态及氮肥利用率皆得到显著促进。低水平PASP(100 mg/plant)可在一定程度上提高氮肥利用率,但对烤烟根系、叶片光合特性促进效果不显著;相比较而言,较高水平PASP(400 mg/plant)更有利于烤烟根系和叶片的生理代谢及肥料利用率的提高。相关分析表明,PASP的添加量与氮肥利用率之间存在极显著正相关关系(p<0.01)。生育后期,各处理的15 N分配率均表现为地上部大于地下部,且随着PASP添加量的增加,植株分配到地上部的15 N的量相应增加;此外,施用PASP显著降低了氮肥损失率,提高了氮肥总回收率,表现为PASP用量越高效果越明显。综上可知,施用PASP促进了烤烟生理代谢和氮素的吸收,降低了氮肥损失,以施400 mg/plant PASP效果最佳。

With the excellent performance of fertilizer synergist,polyaspartic acid(PASP)may have an effect on the physiological metabolism and nitrogen use efficiency of flue-cured tobacco,which will solve the problems of excessive nitrogen application and low nitrogen use efficiency in tobacco-planting,and provide some reference to the application of PASP in tobacco production.A pot experiment which took the flue-cured tobacco called‘Yun 87’,and yellow soil,the typical soil of Guizhou Province,was carried out to explore the effects of PASP on the physiological characteristics of tobacco and the fate of nitrogen fertilizer when reducing nitrogen application by 15 N-isotope tracer technique.The results indicated that the reduction of nitrogen fertilizer(30%).and the addition of PASP could effectively improve the utilization rate of nitrogen fertilizer,the improvement effect of N reducing was particularly obvious in the late growth stage of flue-cured tobacco,and PASP application could further enhance the improvement effect.With 30%reduction of nitrogen fertilizer application,the root physiology and leaf photosynthetic characteristics of flue-cured tobacco were significantly affected.Under the same conditions,adding PASP significantly promoted root physiology,leaf physiological morphology and nitrogen use efficiency of flue-cured tobacco.The low level PASP(100 mg/pant)didn’t showed significant promotion effect on photosynthetic characteristics of flue-cured tobacco roots and leaves,even though it improved nitrogen utilization rate to some extent.Conversely,the high-level PASP(400 mg/pant)were more conducive to the physiological metabolism of roots and leaves of flue-cured tobacco and increased fertilizer use efficiency.In addition,the result of correlation analysis indicated that there was a significant positive correlation between PASP addition and nitrogen use efficiency(p<0.01).Furthermore,the application of PASP significantly increased the total recovery of nitrogen fertilizer,and for tobacco plant,the 15 N distribution of aerial part was higher than that of underground part in all treatments during the late growth stage,both of them became higher with the increase of PASP.In conclusion,the application of PASP facilitated the physiological metabolism of flue-cured tobacco,N absorption,and minimize nitrogen loss,especially in the treatment of N reduced by 30%+PASP 400 mg/plant.