Changes in Soil Organic Carbon and Carbon Fractions Under Different Land Use and Management Practices After Development From Parent Material of Mollisols
Changes in Soil Organic Carbon and Carbon Fractions Under Different Land Use and Management Practices After Development From Parent Material of Mollisols
复制标题
DOI：
10.1097/ss.0000000000000059
复制
发表时间：
2014-04
期刊：
影响因子：
--
通讯作者：
M. You;M. Burger;Lu‐Jun Li;W. Zou;Na Li;Y. Qiao;Xiaozeng Han
中科院分区：
文献类型：
--
作者：
M. You;M. Burger;Lu‐Jun Li;W. Zou;Na Li;Y. Qiao;Xiaozeng Han
摘要土壤有机碳（SOC）是农业生态系统土壤养分状况的重要指标。我国东北地区土壤有机碳含量高，土壤侵蚀严重，土壤母质裸露或接近地表，已引起人们对粮食安全的关注。中国软土是由母质发育的第四纪壤质黄土形成的。为了有效地恢复成土母质生产力的土壤，信息的影响，土地利用/管理措施的SOC浓度和C组分在中国黑土的黄土母质是必要的。本研究的主要目的是调查在不同的管理措施和土地利用下，发生在母质土壤发育过程中的物理和化学分馏（腐殖物质）的碳固存和碳密度组分的变化。在黄土母质上设置了6个处理，分别为：（1）自然休闲不除草，（2）苜蓿，（3）大豆-玉米轮作（S-M），去除未施肥玉米秸秆，（4）去除化肥玉米秸秆，（5）S-M，化肥玉米秸秆和大豆干粉混合，（6）玉米-玉米轮作（S-M），（7）玉米-玉米轮作（S-M），（8）玉米-玉米轮作（S-M），（9）玉米-玉米轮作（S-M），（10）玉米-玉米轮作（S-M），（10）玉米-玉米轮作（S-M）。（6）S-M，加入化学施肥玉米的生物量，包括谷物。土壤有机碳含量增加15%至77%，这取决于处理。在土壤发育过程中，母质碳组分变化迅速。重质组分C库占总SOC的比例（78%~89%）大于游离轻质组分（2.1%~10.2%）和吸留轻质组分（1.3%~12.9%）。由于不同的土地利用方式和管理措施，作为土壤C变化的指示剂，吸光度比自由光组分更敏感。胡敏素在土壤有机碳中所占比例（29.9%~54.7%）大于富里酸（18.0%~34.4%），富里酸大于胡敏酸（11.8%~14.8%）。研究结果表明，有机碳在黄土母质中的增加取决于有机质输入的类型和数量。与不添加有机质的处理相比，添加地上部分作物生物量和粮食的处理对固碳、密度组分分布和腐殖物质的贡献更大。建议通过最大化生物量投入的管理措施来恢复退化软土的有机碳，以恢复其肥力。
Abstract Soil organic carbon (SOC) is important to soil nutrient status in agroecosystems. Some of the soils of the Northeast of China, noted for their high SOC content, suffer from serious soil erosion to the point of having the parent material exposed or near the surface, which has raised concerns for food security. The Chinese Mollisols were derived from loamy Quaternary loess that developed from parent material. To effectively restore parent material to productive soils, information on the effects of land use/management practices on SOC concentration and C fractions in loess parent material of Chinese Mollisols is needed. The main objective of this study was to investigate the changes in C sequestration and C density fractions by physical and chemical fractionation (humic substances) occurring in the process of soil development from parent material under different management practices and land use. Six treatments were imposed in plots of loess parent material in a 5-year experiment: (1) natural fallow without weed control; (2) alfalfa; (3) soybean-maize rotation (S-M), straw of unfertilized maize removed; (4) S-M, straw of chemically fertilized maize removed; (5) S-M, straw of chemically fertilized maize and dried soybean powder incorporated; (6) S-M, biomass, including grain, of chemically fertilized maize incorporated. The SOC content increased by 15% to 77% depending on treatments. In the process of soil development, the C fractions of the parent material changed rapidly. The heavy fraction C pool accounted for a larger proportion of total SOC (78%–89%) than both the free light fraction (2.1%–10.2%) and the occluded light fraction (1.3%–12.9%) pools. The occluded light fraction was more sensitive than the free light fraction as indicator of soil C changes because of different land use and management practices. Humin accounted for a larger proportion (29.9%–54.7%) of SOC than fulvic acid (18.0%–34.4%), which was larger than the humic acid fraction (11.8%–14.8%). Our results indicate that SOC increase in loess parent material depends on types and amounts of organic matter inputs. The treatments, in which aboveground crop biomass and grain were incorporated, contributed more to C sequestration, distributions of density fraction, and humic substances than the treatments without organic matter. Management practices maximizing biomass inputs are recommended to restore SOC in degraded Chinese Mollisols in order to restore their fertility.