{"title":"巴西东北部降雨梯度上的浮土碳储量","authors":"","doi":"10.1016/j.catena.2024.108295","DOIUrl":null,"url":null,"abstract":"<div><p>Planosols have sandy-textured surface horizons that abruptly cover a dense subsoil with high clay content, which usually limits drainage and influences soil moisture. Here, we investigated changes in C storage through the pedogenic horizons of soil profile, including detailed sampling of A and B horizons along a transect to cover rainfall variation (584–1130 mm year<sup>−1</sup>) and soil cover of Planosols, including dry land areas in Northeast Brazil. The soil profile located under highest precipitation and with the greatest pedogenic development (150 cm) showed the largest C stock (101.91 Mg/ha), surpassing estimates of other soil classes. In addition, our results suggest that soil cover and pedogenesis impact C storage in Planosols. An average of 64 % of C is stored in subsurface horizons that present abundant clay fraction; thus, the dynamics of subsurface soil organic carbon (SOC) appear to be more controlled by soil features than by climate. Values of δ<sup>13</sup>C indicated the predominance of C3 plant, except in area with sugarcane cultivation (C4 plant). Changes in C distribution within the horizon suggest changes in degree of decomposability of soil organic matter (SOM), mainly in A1 and B1 layers, with A horizon richer in labile compounds. δ<sup>15</sup>N values indicated that N dynamics differ in the gradient. The thermal analyses showed that around 70 % or more of humin fraction is composed of structures more resistant to degradation, suggesting that C stock in Planosols has relative stability. However, in driest part of the climate transect, SOM may be more vulnerable to losses due to the large relative quantity of aliphatic groups in soil surface and subsurface. This work provides insights into the mechanisms the determine C storage distribution in tropical Planosols and contributes to appropriate use and management of these soils to ensure the valuable ecosystem service of C storage.</p></div>","PeriodicalId":9801,"journal":{"name":"Catena","volume":null,"pages":null},"PeriodicalIF":5.4000,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Carbon stocks in Planosols along a rainfall gradient in Northeast Brazil\",\"authors\":\"\",\"doi\":\"10.1016/j.catena.2024.108295\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Planosols have sandy-textured surface horizons that abruptly cover a dense subsoil with high clay content, which usually limits drainage and influences soil moisture. Here, we investigated changes in C storage through the pedogenic horizons of soil profile, including detailed sampling of A and B horizons along a transect to cover rainfall variation (584–1130 mm year<sup>−1</sup>) and soil cover of Planosols, including dry land areas in Northeast Brazil. The soil profile located under highest precipitation and with the greatest pedogenic development (150 cm) showed the largest C stock (101.91 Mg/ha), surpassing estimates of other soil classes. In addition, our results suggest that soil cover and pedogenesis impact C storage in Planosols. An average of 64 % of C is stored in subsurface horizons that present abundant clay fraction; thus, the dynamics of subsurface soil organic carbon (SOC) appear to be more controlled by soil features than by climate. Values of δ<sup>13</sup>C indicated the predominance of C3 plant, except in area with sugarcane cultivation (C4 plant). Changes in C distribution within the horizon suggest changes in degree of decomposability of soil organic matter (SOM), mainly in A1 and B1 layers, with A horizon richer in labile compounds. δ<sup>15</sup>N values indicated that N dynamics differ in the gradient. The thermal analyses showed that around 70 % or more of humin fraction is composed of structures more resistant to degradation, suggesting that C stock in Planosols has relative stability. However, in driest part of the climate transect, SOM may be more vulnerable to losses due to the large relative quantity of aliphatic groups in soil surface and subsurface. This work provides insights into the mechanisms the determine C storage distribution in tropical Planosols and contributes to appropriate use and management of these soils to ensure the valuable ecosystem service of C storage.</p></div>\",\"PeriodicalId\":9801,\"journal\":{\"name\":\"Catena\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.4000,\"publicationDate\":\"2024-08-12\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Catena\",\"FirstCategoryId\":\"97\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0341816224004922\",\"RegionNum\":1,\"RegionCategory\":\"农林科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Catena","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0341816224004922","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
浮土的表层为沙质地层,突然覆盖着粘土含量高的致密底土,这通常会限制排水并影响土壤水分。在这里,我们研究了通过土壤剖面的成土层储藏 C 的变化,包括沿横断面对 A 和 B 层进行详细取样,以覆盖巴西东北部干旱地区的降雨量变化(584-1130 毫米/年)和 Planosols 的土壤覆盖情况。降水量最大、成土作用最强(150 厘米)的土壤剖面显示出最大的碳储量(101.91 兆克/公顷),超过了其他土壤类别的估计值。此外,我们的研究结果表明,土壤覆盖和成土作用会影响浮质土壤中的碳储量。平均有 64% 的碳储存在粘土成分丰富的地下地层中;因此,地下土壤有机碳(SOC)的动态似乎更多地受到土壤特性而非气候的控制。δ13C值表明,除甘蔗种植区(C4植物)外,C3植物占主导地位。地层内 C 分布的变化表明,土壤有机质(SOM)的可分解程度发生了变化,主要是在 A1 和 B1 层,A 层的可溶性化合物更丰富。δ15N值表明,氮的动态变化在梯度上有所不同。热分析表明,腐殖质部分约有 70% 或更多是由较难降解的结构组成的,这表明浮质土中的碳储量具有相对稳定性。然而,在气候横断面最干旱的地区,由于土壤表层和地下脂肪族的相对数量较大,SOM 可能更容易受到损失。这项研究深入揭示了热带浮土中碳储量分布的决定机制,有助于合理利用和管理这些土壤,以确保提供宝贵的生态系统碳储量服务。
Carbon stocks in Planosols along a rainfall gradient in Northeast Brazil
Planosols have sandy-textured surface horizons that abruptly cover a dense subsoil with high clay content, which usually limits drainage and influences soil moisture. Here, we investigated changes in C storage through the pedogenic horizons of soil profile, including detailed sampling of A and B horizons along a transect to cover rainfall variation (584–1130 mm year−1) and soil cover of Planosols, including dry land areas in Northeast Brazil. The soil profile located under highest precipitation and with the greatest pedogenic development (150 cm) showed the largest C stock (101.91 Mg/ha), surpassing estimates of other soil classes. In addition, our results suggest that soil cover and pedogenesis impact C storage in Planosols. An average of 64 % of C is stored in subsurface horizons that present abundant clay fraction; thus, the dynamics of subsurface soil organic carbon (SOC) appear to be more controlled by soil features than by climate. Values of δ13C indicated the predominance of C3 plant, except in area with sugarcane cultivation (C4 plant). Changes in C distribution within the horizon suggest changes in degree of decomposability of soil organic matter (SOM), mainly in A1 and B1 layers, with A horizon richer in labile compounds. δ15N values indicated that N dynamics differ in the gradient. The thermal analyses showed that around 70 % or more of humin fraction is composed of structures more resistant to degradation, suggesting that C stock in Planosols has relative stability. However, in driest part of the climate transect, SOM may be more vulnerable to losses due to the large relative quantity of aliphatic groups in soil surface and subsurface. This work provides insights into the mechanisms the determine C storage distribution in tropical Planosols and contributes to appropriate use and management of these soils to ensure the valuable ecosystem service of C storage.
期刊介绍:
Catena publishes papers describing original field and laboratory investigations and reviews on geoecology and landscape evolution with emphasis on interdisciplinary aspects of soil science, hydrology and geomorphology. It aims to disseminate new knowledge and foster better understanding of the physical environment, of evolutionary sequences that have resulted in past and current landscapes, and of the natural processes that are likely to determine the fate of our terrestrial environment.
Papers within any one of the above topics are welcome provided they are of sufficiently wide interest and relevance.