Microbial immobilization of ammonium and nitrate fertilizers induced by starch and cellulose in an agricultural soil
Microbial immobilization of ammonium and nitrate fertilizers induced by starch and cellulose in an agricultural soil
复制标题
DOI：
10.1080/00380768.2020.1843072
复制
发表时间：
2020-11
影响因子：
2
通讯作者：
Q. Ma;Jinsen Zheng;Tetsuhiro Watanabe;Shinya Funakawa
中科院分区：
文献类型：
--
作者：
Q. Ma;Jinsen Zheng;Tetsuhiro Watanabe;Shinya Funakawa
摘要：在农业生态系统中联合施用植物残体和氮肥可以增加氮的固定化，并通过使用新鲜有机物（FOM）的微生物繁殖减少氮的损失。然而，FOM 中不同的碳 (C) 利用率对微生物固定两种形式的氮肥（NH4+-N 和 NO3--N）的影响仍不清楚。本研究以淀粉（高利用率）和纤维素（低利用率）代表农作物秸秆中不同的多糖，研究了它们对两种形式的肥料氮（NH4+-N和NO3--N）固定化的影响。添加多糖和 15N（99.9 原子%）（2.1 g C kg−1 土壤和 100 mg N kg−1 土壤）后，我们在 48 天内测量了土壤呼吸并追踪了固定肥料氮。添加淀粉会迅速耗尽矿物质 N（第 3 天），而纤维素会导致缓慢但连续的固定，持续 4 周。尽管C和N输入量相同，但纤维素处理中的最大肥料-N固定化低于淀粉处理，并且对于NH4+-N和NO3--N形式分别占添加N的56%和40%。在纤维素处理过程中，NH4 +-N 比 NO3 -N 优先被固定，但当矿物质 N 充足时，在淀粉处理中也会发生这种情况。我们的结果表明，很大程度上决定了肥料氮固定的速率和能力，而不是碳的丰度，而是微生物对碳的利用率。此外，NH4+-N的优先固定化凸显了使用铵基肥料可以提高肥料-N固定化水平。
ABSTRACT Combined applications of plant residues and nitrogen (N) fertilizer in agroecosystems may increase N immobilization and reduce N loss through microbial propagation using fresh organic matter (FOM). However, the effects of different carbon (C) availabilities in FOM to microbes on the immobilization of two forms of fertilizer-N (NH4 +-N and NO3 −-N) are still not clear. In this study, starch (high availability) and cellulose (low availability) were used to represent different polysaccharides in crop residues, and their effects on the immobilization of two forms of fertilizer-N (NH4 +-N and NO3 −-N) were investigated. Following the additions of polysaccharides and 15N (99.9 atom %) (2.1 g C kg−1 soil and 100 mg N kg−1 soil), we measured soil respiration and traced immobilized fertilizer-N over 48 days. The starch addition quickly depleted mineral N (on day 3) while cellulose caused a slow but continuous immobilization for 4 weeks. Despite the same amount of C and N input, the maximum fertilizer-N immobilization in the cellulose treatment was lower than in the starch treatment and accounted for 56% and 40% of added N for NH4 +-N and NO3 −-N forms, respectively. NH4 +-N was preferentially immobilized over NO3 −-N in the cellulose treatment during incubation, but it also occurred in the starch treatment when mineral N was sufficient. Our results suggest that it was not the abundance of C, but rather the availability of C to microbes, that strongly determined the rate and capacity of fertilizer-N immobilization. Further, the preferential immobilization of NH4 +-N highlighted that the use of ammonium-based fertilizer can increase the level of fertilizer-N immobilization.