Methane uptake in semiarid farmland subjected to different mulching and nitrogen fertilization regimes

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• 作者：Jianliang Liu ; Xinping Chen ; Ai Zhan ; Shasha Luo…
• 关键词：Methane uptake ; Plastic film mulching ; Gravel mulching ; Nitrogen fertilization ; Semiarid areas ; Soil variables
• 刊名：Biology and Fertility of Soils
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：52
• 期：7
• 页码：941-950
• 全文大小：969 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Life Sciences
  Agriculture
  Soil Science and Conservation
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-0789
• 卷排序：52

文摘

Methane (CH₄) uptake by dryland soils is an important part in the global CH₄ budget and is sensitive to the management practice. This research measured the annual CH₄ flux over 2 years at the rain-fed maize fields in semiarid northwestern China using the static chamber technique. Methane uptake was measured under three mulching practices with the same nitrogen (N) application: no mulching (NM), gravel mulching (GM), and plastic film mulching (FM). In addition, methane uptake was also measured under film mulching management and three different N fertilizer rates: 0 (N0), 250 (N250), and 380 (N380) kg N ha−1. The results showed that the rain-fed maize fields acted as a sink for CH₄, with the annual mean uptake rate of 21.3–40.8 μg CH₄-C m−2 h−1. The soil CH₄ uptake was positively correlated with soil temperature, but negatively correlated with soil moisture; these two factors together explained 35.5–50.9 % of the variance in CH₄ uptake. Compared to the NM treatment, the mulching treatments markedly increased the topsoil temperature, but the annual CH₄ uptake was significantly reduced by 5.2–6.7 % in the GM treatment and by 26.3 % in the FM treatment, most likely because the increased soil moisture restricted CH₄ oxidation and diffusion. The CH₄ uptake showed an increasing tendency with the N rate, probably because N fertilization decreased soil moisture and increased soil NO₃− content. These results help in understanding the effects of agricultural managements on CH₄ uptake and to properly assess the role of dryland soils in the global CH₄ budget.