文献类型： 外文期刊

作者： Chen, Zengming ¹ ; Xu, Yehong ¹ ; Cusack, Daniela F. ³ ; Castellano, Michael J. ⁴ ; Ding, Weixin ¹ ;

作者机构： 1.Chinese Acad Sci, Inst Soil Sci, State Key Lab Soil & Sustainable Agr, Nanjing 210008, Jiangsu, Peoples R China

2.Jiangsu Acad Agr Sci, Instinee Agr Resources & Environm, Nanjing 210014, Jiangsu, Peoples R China

3.Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90095 USA

4.Iowa State Univ, Dept Agron, Ames, IA 50011 USA

关键词： C-13 CPMAS NMR; Cellulose; Lignin; Litterbags; Manure decomposition; N fertilization

期刊名称：GEODERMA （ 影响因子：6.114； 五年影响因子：6.183 ）

ISSN： 0016-7061

年卷期： 2019 年 353 卷

页码：

收录情况： SCI

摘要： Nitrogen (N) input rapidly increases available N in natural and managed ecosystems, potentially altering key ecosystem processes like decomposition. The effect of N enrichment on decomposition rates may be affected by the chemical quality of organic matter (OM), and the extent of N increment. Manure decomposition is an important process in agricultural systems, releasing nutrients and contributing to carbon (C) cycling. However, its response to N fertilization is poorly understood. To help address this knowledge gap, we decomposed pig manure (PM) and chicken manure (CM) under two rates of N fertilization (N1, 75 kg N ha(-1); N2, 112.5 kg N ha(-1)) in a cropland in northeast China. We used litterbags to determine the dynamics of manure decomposition, while monitoring changes in the molecular composition with solid-state C-13 nuclear magnetic resonance (NMR) spectroscopy. After one-year, the decomposition rate of PM was significantly greater than CM (0.516 vs. 0.483 year(-1)). Spectra of C-13 NMR indicated that PM initially contained more O-alkyl C and di-O-alkyl C (representing cellulose). In contrast, the contents of alkyl C (representing lipids) and aromatic C (representing lignin) were less in PM than CM, such that PM was overall more easily degradable. There was no N rate effect on CM decomposition. However, the decomposition rate of PM was significantly lower under high N than low N (0.410 vs. 0.622 year(-1)), apparently related to suppressed degradation of O-alkyl C and di-O-alkyl C. This result was surprising, since N enrichment is generally expected to promote degradation of more labile compounds like cellulose. At the same time, the loss of syringyl monomer of lignin in PM was reduced by high N fertilization. Together, these results suggest that decreased losses of O-alkyl C and di-O-alkyl C may have resulted from physical association of cellulose with more resistant lignin compounds. Net N mineralization was observed from manure decomposition and was greater for CM than PM, and high N fertilization suppressed N release from PM. Overall, our findings suggest that high rate of N fertilization may slow the decomposition of otherwise labile manure, potentially promoting greater C retention in soils.