Film mulching, residue retention and N fertilization affect ammonia volatilization through soil labile N and C pools
Film mulching, residue retention and N fertilization affect ammonia volatilization through soil labile N and C pools
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DOI：
10.1016/j.agee.2020.107272
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发表时间：
2021-03-01
影响因子：
6.6
通讯作者：
Wang, Linquan
中科院分区：
文献类型：
--
作者：
Li, Huitong;Wang, Lv;Wang, Linquan
氨挥发是农业生态系统氮素循环的重要过程，与大气环境质量密切相关。研究了耕作方式和氮肥施用对土壤活性碳、氮库的影响及其对麦田氨挥发的影响。在2017年和2018年进行了连续两年的田间试验。采用裂区设计，研究了3种耕作方式（常规耕作（CT）、地膜覆盖（FM）、秸秆还田（SM））和3种施氮量（对照量（N 0）、144 kg N ha（-1）（N144）、180 kg N ha（-1）（N180））对水稻产量的影响。结果表明，施氮后40 d内NH3挥发量最大，2周后达到峰值。FM能显著降低两季氨挥发峰值、氨累积损失量和氨损失率（p < 0.05）。两个生长季化肥氨损失率（AFR）分别为3.70%~ 3.95%、1.90%~ 2.10%和3.47%~ 3.87%。在小麦栽培过程中，FM提高了表层土壤含水量（SWC）、土壤温度（ST）和矿质氮（NH_4 ~+-N和NO_3 ~--N）。微生物量氮（MBN）和溶解性有机碳（DOC）含量以SM最高。抽穗期秸秆还田可增加水溶性有机氮和硝态氮的含量。氨挥发与土壤NH 4 +-N含量密切相关，NH 4 +-N含量来源于不施肥条件下有机氮的矿化，且受施氮量和土壤含水量的显著影响。施氮增加了土壤NH 4 +-N含量和氨挥发量，施氮量越大，NH3挥发量越大。地膜覆盖增加了土壤含水量、土壤微生物量氮和土壤矿质氮，提高了NH_4 ~+-N含量和NH_3挥发潜力，但膜障最终减轻了氨挥发。秸秆还田条件下，DOC、MBN和ST是影响土壤NH 4 +-N含量和NH3排放的关键因子，并通过微生物增殖对土壤的固定化、矿化和硝化作用产生显著影响。总体而言，施氮促进了土壤氨挥发;秸秆还田可通过物理屏障或封育减缓土壤氨挥发，而秸秆还田对土壤氨挥发影响不明显。
Ammonia (NH3) volatilization was a vital process of the nitrogen cycle in agricultural ecosystems and closely related to the atmospheric environment quality. To investigate the tillage practice and N fertilization impact on the soil labile C, N pools and their effects on ammonia volatilization from wheat fields. A two-year consecutive field experiment was conducted at 2017 and 2018. The split-plot design of three tillage systems (conventional tillage (CT), film mulching (FM), straw residue incorporated into soil (SM)) and three nitrogen rates (the control rate (N0), 144 kg N ha(-1) (N144), 180 kg N ha(-1) (N180)) was applied. The results showed that the NH3 volatilization occurred during 40 days and peaked in 2 weeks post N fertilization. FM could significantly cut down ammonia volatilization peaks, cumulative NH3 loss and ammonia loss rate during both seasons (p < 0.05). The average fertilizer ammonia loss rates (AFR) in two growth seasons were 3.70% - 3.95%, 1.90% - 2.10% and 3.47% - 3.87% for CT, FM and SM separately. The topsoil water content (SWC) and soil temperature (ST), mineral nitrogen (NH4+-N and NO3--N) were enhanced by FM during the wheat cultivation. The microbial biomass nitrogen (MBN) and dissolved organic carbon (DOC) contents of SM were higher than others. Water extraction organic nitrogen (WEON) and NO3--N could be augmented by straw addition during heading stage growth. The ammonia volatilization was closely related with soil NH4+-N content, which was originated from the organic N mineralization in no fertilization condition and significantly affected by ST and SWC. N fertilization increased soil NH4+-N content and ammonia volatilization, and the higher N rate was, the more NH3 volatilization. When film mulching, WEON, MBN and soil mineral nitrogen have been augmented by higher SWC and ST, which increased NH4+-N content and NH3 volatilization potential, nevertheless film barriers mitigated the ammonia volatilization ultimately. Under straw incorporation, DOC, MBN and ST, which significantly affected the immobilization, mineralization and nitrification through microorganism proliferation, were the key factors affecting soil NH4+-N contents and NH3 emission. Overall, N fertilization promoted the ammonia volatilization; FM could mitigate ammonia volatilization through physical barrier or blocking, while the crop residue incorporated into soil had no pronounced impact on the soil ammonia volatilization.