滴灌减氮对植烟土壤无机氮变化及烟株氮积累的影响

为明确滴灌施肥条件下减量施氮对土壤无机氮变化特征、烟株氮积累规律的影响,于2016年在登封进行了田间试验,试验共设置5个处理:T0:不施氮肥;T1:常规施肥;T2:减氮15%;T3:减氮30%;T4:减氮45%。分析了0~20、20~40、40~60 cm土层无机氮含量及烟株氮积累量变化,并对0~20 cm土层无机氮含量拟合曲线及烟株氮积累拟合曲线特征值进行分析。结果表明,滴灌施肥能够显著提高栽后40、50 d时0~20 cm土层无机氮含量,显著降低栽后50 d时40~60 cm土层无机氮含量;减氮15%~30%对烟叶产量、生育期内烟株氮素积累量均无显著影响,减氮45%烟叶产量、烟株氮积累量、烟叶氮积累量分别显著下降11.52%、10.53%、10.50%;氮肥农学效率(NAE)、氮肥偏生产力(NPFP)均以T4处理最高,且随施氮量增加逐渐下降,氮肥表观利用率(ARE)以T3处理最高,氮收获指数(NHI)、氮肥生理利用率(NPE)与施氮量间无明显关系。减施氮肥土壤无机氮下降持续时间及烟株氮素快速增长时间会延长,无机氮最大下降速率及烟株最大氮积累速率降低,不利于烟株氮素快速积累。因此,综合考虑认为,在该地区条件下,滴灌施肥减氮15%~30%有利于氮肥高效应用。

Effects of Nitrogen Reduction with Drip Fertigation on Soil Inorganic Nitrogen and Nitrogen Accumulation in Tobacco

In order to clarify the effects of reducing nitrogen application on the changes of soil inorganic nitrogen and nitrogen accumulation in tobacco plants under drip fertigation, a field experiment was carried out in 2016 in Dengfeng of Henan province, which included five treatments: T0 no nitrogen fertilization; T1 conventional fertilization; T2 15% reduction of nitrogen; T3 30% reduction of nitrogen; T4 45% reduction of nitrogen. The changes of inorganic nitrogen contents in soil layer of 0~20 cm, 20~-40 cm and 40~60 cm and nitrogen accumulation in tobacco plants were analyzed. The correlation between the characteristics values of fitting curves of inorganic nitrogen accumulation in 0~20 cm soil layer and nitrogen accumulation in tobacco plant was analyzed. The results showed that, drip fertigation could significantly increase inorganic nitrogen content in 0~20 cm soil in 40 and 50 days after planting and significantly reduce soil inorganic nitrogen content of 40~60 cm soil in 50 days. 15%~30% reduction of nitrogen had no significant effect on the yield of tobacco leaves and on the nitrogen accumulation in tobacco plants, but the yield and nitrogen accumulation of tobacco leaves and plant decreased significantly by 11.52%, 45%, 10.53% and 10.50% respectively under 45% reduction of nitrogen. Nitrogen agronomic efficiency (NAE) and nitrogen partial factor productivity (NPFP) were the highest in T4, and gradually decreased with the increase of nitrogen rate. Apparent recovery efficiency (ARE) of nitrogen fertilizer was the highest in T3. Nitrogen harvest index (NHI) and nitrogen physiological efficiency (NPE) had no obvious relationship with the nitrogen rate. However, the decrease of nitrogen rate could prolonged the decrease duration of inorganic nitrogen and the rapid growth stage of tobacco plants, and reduse the maximum decrease rate of inorganic nitrogen and the maximum nitrogen accumulation rate of tobacco plants, which is adverse to the rapid accumulation of nitrogen in tobacco plants. Therefore, it is considered that under the conditions of this region reducing nitrogen by 15%~30% under drip fertigation is beneficial to the efficient utilization of nitrogen fertilizer.