Response of soil organic carbon and nitrogen stocks to soil erosion and land use types in the Loess hilly-gully region of China
Response of soil organic carbon and nitrogen stocks to soil erosion and land use types in the Loess hilly-gully region of China
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DOI：
10.1016/j.still.2016.10.004
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发表时间：
2017-03-01
影响因子：
6.5
通讯作者：
Zeng, Guangming
中科院分区：
文献类型：
--
作者：
Li, Zhongwu;Liu, Chun;Zeng, Guangming
在景观尺度上，侵蚀影响土壤和土壤有机碳（SOC）的垂直和水平分布格局。为进一步了解退耕还林后水土流失对黄土丘陵沟壑区土壤有机碳和总氮（TSN）储量的影响与土地利用类型的关系，在人工草地（AGL）、天然草地（NGL）和刺槐人工林（AFL） 3种土地利用类型下的3个景观位置，分析了土壤有机碳、TSN和铯-137 （Cs-137）含量。结果表明：20世纪50年代中期以来，所有土地利用方式均经历了相当大的净侵蚀，平均总损失深度为AFL 2.05 cm, AGL 1.49 cm, NGL 0.54 cm；在0 ~ 100 cm土层中，AFL和NGL土壤有机碳储量分别比AGL低72.3%和26.2%，土壤剖面各层土壤有机碳储量与TSN储量呈显著正相关（R-2 > 0.90）。结果表明，与其他土地利用类型相比，AGL具有更强的固碳能力和TSN固碳能力。AFL和NGL中SOC和TSN含量与Cs-137含量呈显著正相关（AFL的R-2分别为0.97、0.97，NGL的R-2分别为0.90、0.90,n=3），而AGL中Cs-137含量无显著相关（R-2分别为0.41、0.01,n=3）。结果表明，在黄土丘陵沟壑区，AGL是缓解土壤碳氮流失、增加碳氮固存的最佳选择。1999年以来造林后土壤有机碳和总氮的分布格局应考虑一个复杂的过程。(C) 2016 Elsevier B.V.版权所有
Erosion influences the vertical and horizontal distribution patterns of soil and soil organic carbon (SOC) at a landscape scale. To further understand the effect of erosion on SOC and total soil nitrogen (TSN) stocks in relation to land use types after the implementation of the "Grain for Green" program in the Loess hill gully region, the SOC, TSN, and Caesium-137 (Cs-137) contents were analyzed at three selected landscape positions under three land-use types: artificial grassland (AGL), native grassland (NGL) and artificial plantation of Robinia pseudoacacia (AFL). The results showed that all land uses experienced considerable net erosion since the mid-1950s, with an average total loss depth of 2.05 cm for AFL, 1.49 cm for AGL, and 0.54 cm for NGL. The SOC stocks in AFL and NGL were 72.3% and 26.2% lower, respectively, than that in AGL in the 0-100 cm soil layer, and significant positive correlation between SOC and TSN stocks on each layer in the soil profile was observed (R-2 > 0.90). The result showed that compared with other land-use types, AGL had a greater SOC and TSN sequestration capacity. The contents of SOC and TSN were positively correlated with the amount of Cs-137 in AFL and NGL (R-2 = 0.97, 0.97 for AFL, respectively, and R-2 = 0.90, 0.90 for NGL, respectively; n=3), whereas no significant correlation was found in AGL (R-2 = 0.41, 0.01, respectively; n = 3). The results indicated that AGL was an optimal choice to mitigate soil carbon and nitrogen loss and to increase C and N sequestration in the Loess hilly-gully region. A complex process should be considered for the distribution patterns of SOC and TSN after afforestation since 1999. (C) 2016 Elsevier B.V. All rights reserved.