俞月凤, 韦建华, 张俊辉, 李婷婷, 胡钧铭, 郑富海, 何铁光. 喀斯特地区不同碳酸盐岩发育耕地土壤团聚体稳定性及有机碳剖面分布特征[J]. 土壤通报, 2024, 55(5): 1292 − 1301. DOI: 10.19336/j.cnki.trtb.2023091902
引用本文: 俞月凤, 韦建华, 张俊辉, 李婷婷, 胡钧铭, 郑富海, 何铁光. 喀斯特地区不同碳酸盐岩发育耕地土壤团聚体稳定性及有机碳剖面分布特征[J]. 土壤通报, 2024, 55(5): 1292 − 1301. DOI: 10.19336/j.cnki.trtb.2023091902
YU Yue-feng, WEI Jian-hua, ZHANG Jun-hui, LI Ting-ting, HU Jun-ming, ZHENG Fu-hai, HE Tie-guang. Stability of Soil aggregates and Profile Distribution Characteristics of Organic Carbon in Farmland of Different Carbonate Rocks[J]. Chinese Journal of Soil Science, 2024, 55(5): 1292 − 1301. DOI: 10.19336/j.cnki.trtb.2023091902
Citation: YU Yue-feng, WEI Jian-hua, ZHANG Jun-hui, LI Ting-ting, HU Jun-ming, ZHENG Fu-hai, HE Tie-guang. Stability of Soil aggregates and Profile Distribution Characteristics of Organic Carbon in Farmland of Different Carbonate Rocks[J]. Chinese Journal of Soil Science, 2024, 55(5): 1292 − 1301. DOI: 10.19336/j.cnki.trtb.2023091902

喀斯特地区不同碳酸盐岩发育耕地土壤团聚体稳定性及有机碳剖面分布特征

Stability of Soil aggregates and Profile Distribution Characteristics of Organic Carbon in Farmland of Different Carbonate Rocks

  • 摘要:
    目的 探明成土母岩对喀斯特区耕地土壤团聚体稳定性和有机碳分布的影响,为了解喀斯特地区耕地土壤结构及固碳机制提供理论依据。
    方法 选取桂西北喀斯特地区白云岩和石灰岩发育的水田和旱地土壤,通过采集剖面不同深度原状土,基于团聚体的干、湿筛2种分组方法,研究不同碳酸盐岩对农田土壤团聚体含量、团聚体稳定性、团聚体有机碳贡献率及其相关性的影响。
    结果 ①两种母岩发育的耕地土壤机械稳定性团聚体主要分布在> 2 mm粒级,其含量随着土层深度的增加而升高,各粒级团聚体含量均随粒级减小而降低;水稳性团聚体则随着土层深度的增加大粒级团聚体逐渐减少小粒级团聚体逐渐增加,各粒级团聚体含量随粒级减小而先减少后升高或逐渐升高。②随着土层深度的增加,> 0.25 mm团聚体结构破坏率(PAD 0.25)、> 2 mm 团聚体结构破坏率(PAD 2)、机械稳定性团聚体平均重量直径(MWD)和几何平均直径(GMD)均呈升高的趋势,而水稳性团聚体MWD和GMD则呈现逐渐降低的趋势;白云岩发育土壤水稳性团聚体MWD和GMD高于石灰岩发育土壤,同种碳酸盐岩发育下水田土壤的机械稳定性和水稳性团聚体MWD和GMD均高于旱地土壤。③随着土层深度的增加,土壤有机碳含量呈降低趋势,白云岩发育的土壤有机碳含量高于石灰岩发育的土壤,同种碳酸盐岩发育的水田土壤有机碳含量高于旱地土壤;不论是机械稳定性还是水稳性团聚体,> 0.25 mm的大团聚体有机碳贡献率最大;相关分析表明,各粒级团聚体有机碳贡献率与其团聚体含量显著正相关,即团聚体含量越高其有机碳贡献率越高。
    结论 2种碳酸盐岩发育耕地土壤有机碳主要固持在大团聚体中,白云岩发育的土壤比石灰岩发育的土壤具有更高的抗蚀性、结构稳定性和固碳能力。

     

    Abstract:
    Objective The aims were to investigate the influence of different carbonate rocks on the stability of soil aggregates and the distribution of organic carbon (C) in karst farmlands, and then to enhance the understanding of structure and C sequestration mechanism of farmland soil in karst area.
    Methods The paddy field and dry land of dolomite and limestone parent material in karst area of northwest Guangxi were selected, and undisturbed soil of different depth were collected as differential particule sizes and separated by dry sieving and wet sieving to study the influence of different parent materials on soil aggregate content, aggregate stability, contribution rate and correlation of aggregate organic C in farmland were.
    Result ① The mechanical stable aggregates of the two parent materials were mainly distributed in the particle size > 2 mm, and their content increased with the increase of soil depth. The aggregate content of each grain grade decreased with the decrease of particle size. With the increase of soil depth, the large water-stable aggregate decreases gradually and the small water-stable aggregate increases gradually. The aggregate content of each particle size decreased first and then increased or increased gradually with the decrease of particle size. ② Failure rate PAD 0.25, PAD 2, mechanical aggregate MWD and GMD all showed an increasing trend with the increase of soil depth, while the water-stable aggregates MWD and GMD showed a decreasing trend. The MWD and GMD of water-stable aggregates in dolomite parent material were higher than those in limestone parent material. The mechanical stability and water stability MWD and GMD of paddy field were higher than those of dry field under the same carbonate rock development. ③ The soil organic C content decreased with the increase of soil depth. And the soil organic carbon content of the dolomite parent material is higher than that of the limestone parent material. The organic C content of paddy field was higher than that of dry land under the same carbonate rock development. In both mechanical and water-stable aggregates, the contribution rate of organic C were mainly in large aggregates > 0.25 mm. The correlation analysis showed that the organic C contribution rate of each particle size aggregate was significantly positively correlated with the aggregate content, indicating that the higher the aggregate content, the higher the organic C contribution rate.
    Conclusion The soil developed from dolomite parent material has higher corrosion resistance and structural stability than limestone parent material. The organic C of farmland soil under the two parent materials is mainly fixed in the large aggregates

     

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