This work aimed to analyze the dynamics of soil carbon in agricultural areas under different soil management systems and natural ecosystems with Cerrado vegetation. The study was carried out in a grain production area equivalent to soybeans and corn located in the Western region of Bahia State with the adoption of conventional and no-tillage + Brachiaria and vegetable production in the southernmost tip of Piauí State under organic cultivation and vegetable cultivation + no-tillage, besides the native area of the Cerrado. Total organic C content, light organic matter, and soil organic matter were evaluated. Furthermore, the C stock and light organic matter were assessed at four depths (0.0-0.05, 0.05-0.10, 0.10-0, 20, and 0.20-0.40 m). The systems under vegetable cultivation and native area presented the highest levels of C, organic matter, and soil carbon stocks in the superficial layers. However, the NTS + B2 showed higher levels in depth, except for light organic matter. Thus, the content, dynamics, and maintenance of C into the soil are nearly influenced by the management system adopted, both for the lighter fractions of organic matter and the more mineralized forms such as TOC, OSM, and StkC.
The functions that humic acids (HA) can play in the environment are explained by their structural characteristics. Several spectroscopic techniques combined with chemometrics have been used to obtain a better understanding of its structure. Therefore, this work aimed to structurally characterize HA from different sources through spectroscopic techniques combined with the application of chemometrics to relate the environments where HA is formed and its structural characteristics. The HA were extracted and purified from vermicompost, stabilized compost, organic soil, peat, lake sediment and mineral soil. Structural characterization was performed using FTIR-ATR and CP MAS 13 C-NMR and the chemometric analysis of PCA (principal component analysis) and MCR (multivariate curve resolution) was applied to the spectral data. The HA formed in the soil showed a predominance of C Alq -H, R and C Ar -H, R structures, suggesting a greater recalcitrance of this material. The AH formed in the peatlands, despite the predominance of C Alq -H, R and C Ar -H, R, also showed a high presence of carboxylic carbons in its structure. HA formed by composting, vermicomposting and lake sediment processes have a greater presence of functionalized oxygenated structures (C Alk -O,N, C Alk -O and C Alk -di-O, C Ar -O and C COO -H, R) which gives them greater lability and hydrophilicity.As funções que os ácidos húmicos (AH) podem exercem no ambiente são explicadas pelas suas características estruturais. Diversas técnicas espectroscópicas aliadas à quimiometria vêm sendo usadas para obter uma compreensão melhor de sua estrutura. Portanto, este trabalho objetivou caracterizar estruturalmente AH de diferentes origens através de técnicas espectroscópicas aliadas a aplicação de quimiometria para relacionar os ambientes de formação dos AH e as suas características estruturais. Os AH foram extraídos e purificados de vermicomposto, composto estabilizado, solo orgânico (Organossolo), turfa, sedimento de lago e solo mineral (Gleissolo). A caracterização estrutural foi realizada mediante FTIR-ATR e RMN de 13 C via CP/MAS e a análise quimiométrica de ACP (análise de componentes principais) e CRM (curva de resolução multivariada) foi aplicada aos dados espectrais. Os AH formados no solo apresentaram um predomínio das estruturas de C Alquil -H,R e C Aromatico -H,R, sugerindo uma maior recalcitrância desse material. O AH formado nas turfeiras, apesar de apresentar predomínio do C Alquil -H,R e C Aromatico -H,R, também apresentou elevada presença de carbonos carboxílicos em sua estrutura. Já os AH formados por processos de compostagem, vermicompostagem e em sedimentos de lagos apresentam predomínio de estruturas oxigenadas funcionalizadas (C Alquil -O,N, C Alquil -O e C Alquil -di-O, C Aromatico -O e C COO -H,R) o que lhes conferem uma maior labilidade e hidrofilicidade.
The present study aimed to evaluate the interference of the management adopted in Cerrado cultivation areas on the chemical and biological soil attributes. Four soil management systems were studied (MC, NT3+SM, NT6+MB, and NT6+SMB), with different years of adoption and cover crops, and one area of native vegetation (NV). In each soil management system and in the NV, soil samples were collected at the depths of 0.0-0.05m, 0.05-0.10m, and 0.10-0.20m, 5 replications. The effects of the treatments on the response variables were evaluated by ANOVA, and the means were compared by the Scott-Knott test at 5% of significance. Soil management with crop rotation and succession improved soil fertility since all chemical elements studied presented higher values when compared to the NV. The soil contents of organic carbon, macronutrients, microbial biomass carbon (Cmic), and soil basal respiration (SBR) were generally higher on the surface, with the lowest contents of Cmic being observed for the NT6+MB, and the NV presenting high SBR in all studied depths. The metabolic quotient was higher in depth. In general, our results revealed that the use of no-tillage systems, besides providing soil cover, also increases and maintains the chemical and biological attributes, respectively, thus improving soil quality.
IntroduçãoO uso sustentável dos recursos naturais, especialmente do solo e da água, tem-se constituído em tema de crescente relevância, em razão do aumento das atividades antrópicas, consequentemente, cresce a preocupação com o uso sustentável e a qualidade desses recursos (ARAÚJO et al., 2007). Assim, qualquer alteração no solo pode alterar diretamente sua estrutura e sua atividade biológica e consequentemente, sua fertilidade, com reflexos nos agroecossistemas, podendo promover prejuízos à qualidade do solo e à produtividade das culturas (BROOKES, 1995).Diante disso, a variação desses atributos, determinada pelo manejo e uso do solo, e sua avaliação são importantes para a escolha do melhor manejo visando à sustentabilidade do sistema e manter a qualidade do solo.Neste contexto, o presente trabalho objetivou pesquisar e aperfeiçoar conhecimentos acerca da qualidade do solo através da avaliação da atividade microbiana do solo em diferentes sistemas de manejo em área de cerrado. Fundamentação TeóricaA atividade dos organismos é considerada um atributo positivo para a qualidade do solo, sendo a respiração um indicador sensível da decomposição de resíduos, do giro metabólico do carbono orgânico do solo e de distúrbios do ecossistema (PAUL et al., 1999). Podendo ser utilizada como indicador de qualidade do solo em diferentes sistemas de manejo e rotação de culturas, sendo
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.