摘要
以中国科学院阜康荒漠生态站长期定位试验为平台,对不同施肥模式下绿洲农田土壤有机碳(SOC)、颗粒有机碳(POC)、轻组有机碳(LFOC)及团聚体结合碳的剖面(0~3m)特征进行了研究。结果表明:与荒漠土壤相比,20a长期施肥模式下SOC含量在表层(0~0.2m)土壤中增加了14%~56%,但在下层(0.2~0.6m)减少了15%~33%。在深层(0.6~3m),单施化肥(NPK与N2P2K)与化肥配施秸秆处理(NPKR与N2P2R2)具有不同的变化:SOC含量在前者中降低了5%~9%,在后者中增加了4%~9%,POC与LFOC具有相似变化趋势。所有处理均增加了整个剖面的大团聚体(〉0.25mm)结合碳。然而,44%~87%的SOC分布于粉砂与粘粒组分(〈0.053mm)中,在深层土壤中该比例最大(超过80%),揭示了该组分中SOC含量的维持对于碳固定的重要性。单施化肥处理降低了粉砂与粘粒组分中SOC含量,可能是其深层土壤碳损耗的一个机制。化肥配施秸秆处理在促进SOC含量的增加、大团聚体形成方面具有最好效果,尤其在深层土壤。
An investigation was conducted to determine soil profile (0-3 m)changes in SOC, particulate organic carbon (POC), light fraction organic carbon (LFOC), and aggregate-associated carbon in a long-term field experi- ment site in an oasis farmland of the National Field Research Station of Desert Ecosystem in Fukang, Chinese Acade- my of Sciences. The following treatments were compared with the desert soil from which the oasis was created: inor- ganic fertilizer alone (NPK and N2P2K), inorganic fertilizer combined with wheat straw(NPKR and N2P2R2), and no fertilization(CK). The result showed as follows: the SOC contents increased by 14%-56% in the topsoil(0-0.2 m), but decreased by 15%-33% in the subsoil(0.2-0.6 m)under all fertilizer applications of 〉20 years. In the deep layer (0.6-3 m) there were significant differences between the treatments with and without straw: SOC decreased by 5%-9% in treatments without straw, but increased by 4%-9% in treatments with straw. POC and LFOC also had the similar trends. All treatments increased the proportion of macro-aggregates ( 〉0.25 mm) and its associated carbon throughout the soil profile. However, 44%-87% of total SOC was stored in silt+clay fraction, especially in the deep layer. This indicated the importance of SOC stabilization in silt+clay fraction for carbon sequestration. Application of inorganic fertilizer alone led to a significant decrease of SOC content in silt+clay fraction in the deep layer; this should be the main mechanism for SOC loss. Combined application of inorganic fertilizer and straw had the greatest effects on increasing SOC content and enhancing the formation of macro-aggregates, especially for the deep layer.
出处
《干旱区地理》
CSCD
北大核心
2013年第4期637-644,共8页
Arid Land Geography
基金
国家重点基础研究发展计划973项目(2009CB825102)
国家国际科技合作计划(2010DFA92720)资助
关键词
土壤剖面
有机碳(soc)
团聚体
长期实验
绿洲
soil profile
soil organic carbon(SOC)
aggregates
long-term experiment
oasis