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长期退耕对红壤团聚体碳氮磷生态化学计量特征的影响

宋莉群1,2,王义东1*,李冬初3,张会民3,娄翼来4,窦渤凯1,2,尚云涛1,王中良1,2   

  1. (1天津师范大学天津市水资源与水环境重点实验室, 天津 300387;2天津师范大学地理与环境科学学院, 天津 300387;3中国农业科学院农业资源与农业区划研究所, 北京 100081;4中国农业科学院农业环境与可持续发展研究所, 北京 100081)
  • 出版日期:2019-06-10 发布日期:2019-06-10

Long-term effects of natural restoration on C∶N∶P ecological stoichiometry in aggregates of red soil.

SONG Li-qun1,2, WANG Yi-dong1*, LI Dong-chu3, ZHANG Hui-min3, LOU Yi-lai4, DOU Bo-kai1,2, SHANG Yun-tao1, WANG Zhong-liang1,2   

  1. (1Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387, China; 2School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China; 3Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, hina; 4Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China).
  • Online:2019-06-10 Published:2019-06-10

摘要: 目前,长期退耕恢复如何影响红壤团聚体组成及其碳氮磷生态化学计量特征还不十分清楚。本研究基于湖南红壤试验站连续27年的长期定位试验,选取常规施肥耕作和退耕恢复两个处理,采集0~15 cm耕层土样,利用湿筛法探讨了土壤团聚体粒级组成及其碳氮磷含量与生态化学计量特征对长期退耕的响应规律。结果显示:相比于常规施肥耕作方式,退耕恢复处理下:①土壤水稳性大团聚体(>0.25 mm)总量显著增加,微团聚体(0.053~0.25 mm)和矿质颗粒(<0.053 mm)含量显著降低;②土壤有机碳和全氮含量显著增加,全磷含量显著降低,其中有机碳含量在各个粒级团聚体中均显著增加,全氮含量则在大团聚体(>2和0.25~2 mm)与微团聚体(0.053~0.25 mm)中显著增加,而全磷含量在各粒级团聚体中均显著降低。另外,0.25~2 mm粒级大团聚体对土壤碳氮磷养分贡献率最高;③土壤C∶N、C∶P和N∶P显著升高,但C∶N在各粒级团聚体中表现较为稳定,而C∶P和N∶P变异性较大,在各粒级土壤团聚体中均有显著升高。综上,退耕恢复增强了耕层土壤的团聚作用,使碳、氮、磷更集中赋存于大团聚体中,对土壤结构、团聚体质量有改善作用,但对于磷素限制作用的增强值得今后注意。

关键词: 长期施肥, 秸秆还田, 木质素, 土壤酶活性, 积累特性

Abstract: It is not clear how long-term natural restoration affects soil aggregate distribution and C∶N∶P ecological stoichiometric characteristics in red soil. Soil samples (0-15 cm depth) were taken from two treatments, conventional farming (CF) and natural restoration (NR), in a 27-year field experiment in Hunan Red Soil Experimental Station. The aim of this study is to investigate the response of soil aggregate distribution and the contents and stoichiometric ratios of soil organic C (SOC), total N (TN) and total P (TP) to long-term natural restoration. Compared with CF, (1) The total soil waterstable macroaggregates (>0.25 mm) in NR significantly increased, and the proportion of microaggregates (0.053-0.25 mm) and mineral particles(<0.053 mm) significantly decreased; (2) The contents of SOC and TN in bulk soil of NR significantly increased. While the SOC content significantly increased in each aggregate size class, TN content in macroaggregates (>2 and 0.25-2 mm) and microaggregates (0.053-0.25 mm) significantly increased. In contrast, TP content significantly decreased in bulk soil and each aggregatesize fraction. The 0.25-2 mm aggregate size class contributed most of nutrients in the bulk soil. (3) The ratios of C∶N, C∶P and N∶P in bulk soil of NR significantly increased. The C∶N ratio of the four aggregates remained constant, while C∶P and N∶P showed greater variability and significantly increased in each aggregate size class. In conclusion, long-term natural restoration enhances soil aggregation effect, which results in more concentrated C, N and P in macroaggregates. While natural restoration can improve soil structure and aggregate quality, attention should be paid to the exacerbated phosphorus limitation in future.

Key words: long-term fertilization, returning straw to field, lignin, accumulation characteristics, soil enzyme activity.