Soil organic carbon and total nitrogen in intensively managed arable soils

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• 作者：Yun Yan^a ; ^b ; ¹ ; Jing Tian^a ; ¹ ; Mingsheng Fan^a ; ^{fanms@cau.edu.cn} ; Fusuo Zhang^a ; Xiaolin Li^a ; Peter Christie^a ; ^c ; Haiqing Chen^a ; Juhwan Lee^b ; Yakov Kuzyakov^d ; Johan Six^b
• 关键词：SOC ; soil organic carbon ; SOM ; soil organic matter ; TN ; total soil nitrogen ; iPOM ; intra-aggregate particulate organic matter
• 刊名：Agriculture ; Ecosystems & Environment
• 出版年：2012
• 期刊代码：6_01678809
• 类别：abs
• 出版时间：15 March, 2012
• 卷：150
• 期：Complete
• 页码：102-110
• 文件大小：618 K

摘要

The conversion from cereal fields to vegetable production in the last three decades represents a significant shift in land use in China. Here, we studied the effects of conversion form cereal fields to vegetable production in north China on soil organic carbon (SOC) and total nitrogen (TN) in both bulk soil and soil aggregates. We used two approaches: (1) measurements of paired soil samples from wheat (Triticum aestivum L.) - maize (Zea mays L.) fields and adjacent greenhouses vegetable fields in three vegetable production areas representing various management intensities in terms of C and N inputs and frequency of tillage; (2) fractionating soil to distinguish intra-aggregate particulate organic matter (iPOM) and organo-mineral complexes (silt + clay). Our results indicated that converting cereal fields to greenhouse vegetable production with intermediate and high management intensity led to increases in SOC and TN and decreases in C:N ratios in the top soil. The accumulation rates of C and N in the surface soil (0-30 cm) were estimated to be 1.37 Mg C ha^鈭? yr^鈭? and 0.21 Mg N ha^鈭? yr^鈭? over an average period of 8 years after cereal fields to greenhouse vegetable production conversion. At the soil aggregate level, only the coarse (>250 渭m) and fine (53-250 渭m) iPOM fraction contributed to the increases in soil C (e.g., 49%and 51%of total C increases, respectively), while the coarse and fine iPOM, and silt + clay fraction accounted for 22%, 30%and 48%, respectively, of total N increases. This illustrates how the addition of readily available C (manure) and N (manure and inorganic N) leads to a temporary stabilization of C in relatively labile SOM fractions, but to a preferential stabilization of N in organo-mineral SOM fractions. In conclusion, the conversion to highly intensive vegetable systems in China leads to marked differences in C and N stabilization dynamics.