Denitrification characteristics of subtropical soils in China affected by soil parent material and land use
Denitrification characteristics of subtropical soils in China affected by soil parent material and land use
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DOI：
10.1111/j.1365-2389.2007.00923.x
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发表时间：
2007-12
影响因子：
4.2
通讯作者：
Y. B. Xu;Zucong Cai
中科院分区：
文献类型：
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作者：
Y. B. Xu;Zucong Cai
在中国亚热带地区江西省的稻田（R）、茶园（T）、林地（F）、灌木林地（B）和高地（U）采集了45个土壤样品。这些土壤来源于第四纪红土（Q）、第三纪红砂岩（S）和花岗岩（G）。在用200 mg NO3− − N kg−1土壤处理后，通过在30°C的顶部空间中的N2气体下测量28天厌氧培养期间NO3− − N含量的变化来确定其反硝化能力。这里研究的亚热带土壤的特点是反硝化能力一般很小，从没有反硝化能力到在培养11天内完全消失。除了少数例外，NO3− − N还原与孵育时间遵循一级关系，反应常数为0 - 0.271天-1，但数据可以通过对数关系更好地模拟。因此，反硝化能力由一级反应的反应常数、对数关系的斜率和厌氧培养前7天的平均NO3− − N还原速率（范围为0 - 28.5 mg kg−1day−1）决定，除稻田外，所有土地利用中G来源的土壤的反硝化能力均显著高于Q和S来源的土壤。土壤有机碳和氮的有效性是决定三种成土母质反硝化能力差异的关键因素。与其他4种土地利用方式相比，水稻种植显著提高了土壤反硝化能力，但掩盖了土壤母质对反硝化能力的影响。这很可能是由于土壤中有机碳和全氮含量增加，促进了水稻土淹水时能够进行厌氧呼吸的微生物的数量和生物活性。无论是旱地土壤pH值的增加所造成的高地作物生产，也不是茶园土壤pH值的降低，茶树的酸化作用改变土壤反硝化能力。我们的研究结果表明，土地利用和管理措施有利于土壤碳和/或氮的积累和厌氧微生物活动提高土壤反硝化能力。
Forty‐five soil samples were collected from rice paddy land (R), tea garden land (T), forestland (F), brush land (B), and upland (U) in Jiangxi province, a subtropical region of China. These soils were derived from Quaternary red earth (Q), Tertiary red sandstone (S), and granite (G). Their denitrification capacities were determined after treatment with 200 mg NO3−‐N kg−1 soil by measuring changes in NO3−‐N content during a 28‐day anaerobic incubation under N2 gas in the headspace, at 30°C. The subtropical soils studied here were characterized by generally small denitrification capacities, ranging from no denitrification capacity to complete disappearance of added NO3−‐N within 11 days of incubation. With few exceptions, NO3−‐N reduction with incubation time followed a first‐order relationship with reaction constants of 0 – 0.271 day−1, but the data could be simulated better by a logarithmic relationship. Thus, denitrification capacity was determined by the reaction constant of the first‐order reaction, the slope of the logarithmic relationship, and the averaged NO3−‐N reduction rate in the first 7 days of anaerobic incubation (ranging from 0 to 28.5 mg kg−1day−1), and was significantly larger in the soils derived from G than from Q and S for all land uses except for rice paddy land. Soil organic carbon and nitrogen availability are the key factors that determine differences in denitrification capacity among the three soil parent materials. Rice cultivation significantly promoted denitrification capacity compared with the other four land uses and masked the effect of soil parent materials on denitrification capacity. This is most likely due to increases in organic carbon and total N content in the soil, which promoted the population and biological activities of microorganisms which are able to respire anaerobically when the rice soil is flooded. Neither the increased pH of upland soil caused by the addition of lime for upland crop production, nor the decreased pH of the tea garden soil by the acidification effect of tea plants altered soil denitrification capacity. Our results suggest that land use and management practices favour soil carbon and/or nitrogen accumulation and anaerobic microorganism activities enhance soil denitrification capacity.