Mechanisms of carbon sequestration and stabilization by restoration of arable soils after abandonment: A chronosequence study on Phaeozems and Chernozems
Mechanisms of carbon sequestration and stabilization by restoration of arable soils after abandonment: A chronosequence study on Phaeozems and Chernozems
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DOI：
10.1016/j.geoderma.2019.113882
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发表时间：
2019-11-15
期刊：
影响因子：
6.1
通讯作者：
Kuzyakov, Yakov
中科院分区：
文献类型：
--
作者：
Kurganova, Irina;Merino, Agustin;Kuzyakov, Yakov
全世界正在进行的2.2亿公顷农田的放弃，通过改善退化的性质和农业后生态系统的中长期碳(C)固存，极大地促进了土壤恢复。土壤有机碳的分解和稳定这两个相互关联的过程控制着土壤有机碳的动态变化，并影响着原农田的碳源或碳汇功能。我们研究了耕作土壤的废弃对(I)土壤有机碳的积累、组成、稳定性和周转的影响，以及(Ii)微生物活性参数。在俄罗斯欧洲的两个生物气候带：落叶森林(Luvic Phaeozems，PH-Time Sequence)和干旱草原(Calcic Chernozems，CH-TimeSequence)进行了时间序列研究。每个年代序列包括一个可耕作的土壤，3-4个在不断增加的时间段(长达35年)废弃的土壤，以及天然土壤：从未种植过的黑土和完全恢复的黑钙土。我们结合了核磁共振、包括差示扫描量热法和导数热重法在内的热分析、SOC矿化的长期孵化和微生物活性(基础呼吸和微生物C含量)的结果。有机碳含量低的退化黑土在农业后恢复过程中有机碳含量的相对增幅(134%)远高于富含有机碳的黑钙土(38%)。核磁共振和热分析鉴定的所有有机化合物类中都记录了SOC的增加，但顽固性SOC的增加在农业后黑钙土中比在黑土中更明显。农业后生黑钙土的有机碳脂肪性和芳香性均高于黑土。在农业恢复后期，微生物活性和可生物降解的有机碳逐渐增加。由于主要受气候和植被的影响，土壤类型是解释大多数土壤和微生物参数总方差的最大部分(54-88%)的主要因素。结论是，尽管黑钙土和黑土的有机碳含量在农业后恢复过程中都有所增加，但碳的固定和稳定机制取决于气候、植被和农业利用过程中的退化强度。有机化合物的积累是以落叶林和草原为主的原始土壤所特有的，并对微生物活动、碳周转和固着有直接影响。
Abandonment of croplands ongoing on 220 million ha worldwide contributes strongly to soil restoration by improvement of degraded properties and medium- and long-term carbon (C) sequestration in post-agricultural ecosystems. Two interrelated processes - decomposition and stabilization of soil organic carbon (SOC) - govern SOC dynamics and affect the C source or sink functions of former croplands. We investigated how the abandonment of arable soils affects (i) accumulation of SOC, its composition, stability, and turnover during the postagricultural restoration of soils, and (ii) microbial activity parameters. A chronosequence study was carried in two bioclimatic zones of European Russia: deciduous forest (Luvic Phaeozems, PH-chronosequence) and dry steppe (Calcic Chernozems, CH-chronosequence). Each chronosequence included an arable soil, 3-4 soils abandoned at increasing time periods (up to 35 years), and natural soil: never cropped Phaeozem and completely restored Chernozem. We combined the results of nuclear magnetic resonance (NMR), thermal analysis including Differential Scanning Calorimetry and Derivative Thermogravimetry, long-term incubation for SOC mineralization, and microbiological activity (basal respiration and microbial C content). Degraded Phaeozems with low SOC amount had much higher relative increase in SOC content (134%) during the post-agricultural restoration compared to SOC-rich Chernozems (38%). SOC gains were recorded in all organic compound classes identified by NMR and thermal analysis, but the increase of recalcitrant SOC was more pronounced in the postagricultural Chernozems than in the Phaeozems. The post-agricultural Chernozems were characterized by higher SOC aliphaticity and aromaticity than Phaeozems. Microbial activity and biodegradable SOC increased gradually during post-agricultural restoration. Being mostly a function of climate and vegetation, the soil type was the primary factor explaining the greatest portion (54-88%) of the total variance for most soil and microbial parameters. Concluding, despite SOC content increased in both Chernozems and Phaeozems during the postagricultural restoration, the mechanisms of C sequestration and stabilization were dependent on climate, vegetation, and on the degradation intensity during the agricultural use. The accumulation of organic compounds was specific for virgin soils dominating in deciduous forest and steppes, and had direct consequences for microbial activities, C turnover and sequestration.