
Soil organic matter of aggregates physicogenic and biogenic in areas under no-tillage system in the Cerrado, Brazil
Author(s) -
Luiz Alberto da Silva Rodrigues Pinto,
Melania Merlo Ziviani,
Igor de Sousa Morais,
Robert Ferreira,
Wanderson Farias da Silva,
Sandra Santana de Lima,
Cristiane Figueira da Silva,
José Luiz Rodrigues Torres,
Marcos Gervásio Pereira
Publication year - 2021
Publication title -
research, society and development
Language(s) - English
Resource type - Journals
ISSN - 2525-3409
DOI - 10.33448/rsd-v10i5.15012
Subject(s) - brachiaria , total organic carbon , organic matter , carbon fibers , chemistry , agronomy , tillage , environmental chemistry , fractionation , environmental science , forage , biology , materials science , organic chemistry , composite number , composite material
The aim of this study was to evaluate i) the different cover crops contribution used in no-tillage system (NT) to biogenic aggregation; and ii) the influence of aggregate formation pathways on the compartmentalization and the soil organic carbon origin. Two areas managed under NT with different implementation times (6 and 18 years, NT06 and NT18, respectively) and cover crops were evaluated, totaling six sampling areas: NT06, millet (NT06MI); NT06, brachiaria (NT06BR); NT06, sunn hemp (NT06SH); NT18, millet (NT18MI); NT18, brachiaria (NT18BR); NT18, and sunn hemp (NT18SH). In each sampling area, five pseudo-replicates were collected in the 0.00-0.05 and 0.05-0.10 m layers. The samples were air-dried and sieved using sieves with 9.7 and 8.0 mm mesh, and the aggregates retained within this interval were selected. The percentage of each type of aggregate (physicogenic and biogenic) was quantified. Total organic carbon (TOC) and the natural abundance of δ13C (‰) were analyzed and the physical fractionations of SOM were performed: particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) and density fractionation (free light fraction carbon, FLFC). Physicogenic aggregates were quantified in greater proportion, except for the areas of NT06BR and NT18BR in the 0.00-0.05 m layer. The biogenic aggregates showed the highest contents of TOC, POC, MAOC, FLFC and more negative values of δ13C. The use of grasses, especially Brachiaria spp., as cover plants in NT after 6 and 18 years of adoption favors the formation of aggregates through the biogenic pathway and they influence the compartmentalization and origin of stored organic carbon.