Zhang Zhen, Yu Zhenwen, Zhang Yongli, Shi Yu
Key Laboratory of Crop Ecophysiology and Farming System, Ministry of Agriculture, Shandong Agricultural University, Taian, China.
Front Plant Sci. 2022 May 19;13:878424. doi: 10.3389/fpls.2022.878424. eCollection 2022.
Scholars have proposed the practice of split nitrogen fertilizer application (SNFA), which has proven to be an effective approach for enhancing nitrogen use efficiency. However, the combined effects of SNFA on wheat plant nitrogen use efficiency, ammonia (NH) emission flux, as well as the rates of nitrification and denitrification in different ecosystems remain unclear. Meanwhile, few studies have sought to understand the effects of the split nitrogen fertilizer method under water-saving irrigation technology conditions on nitrogen loss. The current study assessed soil NH volatilization, nitrification, and denitrification intensities, as well as the abundance of nitrogen cycle-related functional genes following application of different treatments. Specifically, we applied a nitrogen rate of 240 kg⋅ha, and the following fertilizer ratios of the percent base to that of topdressing under water-saving irrigation: N1 (basal/dressing, 100/0%), N2 (basal/dressing, 70/30%), N3 (basal/dressing, 50/50%), N4 (basal/dressing, 30/70%), and N5 (basal/dressing, 0/100%). N3 treatment significantly reduced NH volatilization, nitrification, and denitrification intensities, primarily owing to the reduced reaction substrate concentration (NO and NH ) and abundance of functional genes involved in the nitrogen cycle (AOB, , and ) within the wheat-land soil. N tracer studies further demonstrated that N3 treatments significantly increased the grain nitrogen accumulation by 9.50-28.27% compared with that under other treatments. This increase was primarily due to an increase in the amount of nitrogen absorbed by wheat from soil and fertilizers, which was caused by an enhancement in total nitrogen uptake (7.2-21.81%). Overall, N3 treatment (basal/dressing, 50/50%) was found to effectively reduce nitrogen loss through NH volatilization, nitrification and denitrification while improving nitrogen uptake by wheat. Thus, its application will serve to further maximize the yield and provide a fertilization practice that will facilitate cleaner wheat production in the North China Plain.
学者们提出了氮肥分期施用（SNFA）的做法，事实证明这是提高氮利用效率的有效方法。然而，氮肥分期施用对小麦植株氮利用效率、氨（NH）排放通量以及不同生态系统中硝化和反硝化速率的综合影响仍不明确。与此同时，很少有研究试图了解节水灌溉技术条件下氮肥分期施用方法对氮素损失的影响。本研究评估了不同处理施用后土壤NH挥发、硝化和反硝化强度，以及与氮循环相关功能基因的丰度。具体而言，我们施用了240 kg·ha的氮肥用量，并在节水灌溉条件下设置了以下基肥与追肥比例：N1（基肥/追肥，100/0%）、N2（基肥/追肥，70/30%）、N3（基肥/追肥，50/50%）、N4（基肥/追肥，30/70%）和N5（基肥/追肥，0/100%）。N3处理显著降低了NH挥发、硝化和反硝化强度，这主要是由于小麦田土壤中反应底物浓度（NO和NH）降低以及参与氮循环的功能基因（AOB、和）丰度降低所致。N示踪研究进一步表明，与其他处理相比，N3处理显著提高了籽粒氮积累量9.50 - 28.27%。这种增加主要是由于小麦从土壤和肥料中吸收的氮量增加，这是由总氮吸收量增加（7.2 - 21.81%）引起的。总体而言，发现N3处理（基肥/追肥，50/50%）能有效减少通过NH挥发、硝化和反硝化造成的氮素损失，同时提高小麦对氮的吸收。因此，其应用将有助于进一步提高产量，并提供一种施肥方式，促进华北平原小麦的清洁生产。
