Browsing by Author "Danilo Ferreira da Silva"

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Bacterial community in biological soil crusts from a Brazilian semiarid region under desertification process
(University of Sao Paolo, 2024) José Israel Pinheiro; Paulo Furtado Mendes Filho; Kaio Gráculo Vieira Garcia; Jarlane Viana Moreira; Danilo Ferreira da Silva; Ademir Sérgio Ferreira de Araújo; Jay Prakash Verma; Vania Maria Maciel Melo; Arthur Prudêncio de Araujo Pereira
Biological soil crusts (BSC) are commonly found in soils in the drylands regions, which can influence stabilization, water retention, nutrient cycling (particularly carbon (C) and nitrogen (N) dynamics), and several ecological processes. However, the composition of BSC in Brazilian soils undergoing the desertification process remains poorly understood. This study aimed to characterize the bacterial community in BSC formed in a Brazilian semiarid region under the desertification process. Thus, a highly desertified region was selected from which 34 BSC samples were collected. The total DNA of the BSC was extracted from 0.5 g samples, and the bacterial community was sequenced by a Next Generation Sequencing (NGS) platform (Miseq – Illumina®) using universal primers (515F and 806R). Bioinformatic analysis was carried out in QIIME (v.1.9), and the Operational Taxonomic Units (OTU) table was constructed following the Sumaclust methodology. The pH of BSC, C, N, and phosphorus contents was analyzed. Our study identified a diverse bacterial community in the BSCs. Cyanobacteria, Chloroflexi, and Proteobacteria phyla presented the greatest relative abundance (%) across the samples. Cyanobacteria were dominated by the orders Nostocales and Leptolyngbyales. The prediction of the putative functions found that mostf OTU were related to phototrophy, photosynthetic cyanobacteria, and photoautotrophy. The study found correlations between bacterial phyla and BSC properties, with Cyanobacteria positively related to C. Chloroflexi, Armatimonadetes, and WPS-2 were negatively correlated with C and N contents. These results suggest the critical roles bacteria communities play in BSCs from the Caatinga biome and highlight the potential impact of environmental factors on their diversity and functions. © 2024, University of Sao Paolo. All rights reserved.
Grazing exclusion restores soil health in Brazilian drylands under desertification process
(Elsevier B.V., 2024) Antonio Yan Viana Lima; Maurício Roberto Cherubin; Danilo Ferreira da Silva; Jaedson Cláudio Anunciato Mota; Francisco Gilcivan Moreira Silva; Ademir Sérgio Ferreira de Araujo; Vania Maria Maciel Melo; Jay Prakash Verma; Arthur Prudêncio de Araujo Pereira
The Brazilian drylands (Caatinga biome) are facing accelerated soil desertification due to human activities (e.g., overgrazing). However, restoration practices (e.g., grazing exclusion), are promising to curb soil desertification and, eventually, increase soil functioning. However, the understanding of soil health (SH) changes, induced by desertification and restoration in the Caatinga biome remains, poorly understood. Here, the SMAF (Soil Management Assessment Framework) was applied to assess the impact of desertification and long-term grazing exclusion on the SH in the Caatinga biome. Three conditions were assessed: i) native vegetation (NV), ii) degraded soil by overgrazing (DE) and iii) restored soil by grazing exclusion (RE). Soil samples (0–10 cm) were collected in both rainy and dry seasons, and chemical (pH, sodium adsorption ratio (SAR), K+, and P), physical (bulk soil density), and biological (soil organic carbon (SOC), microbial biomass carbon (MBC), and β-glucosidase activity) indicators were analyzed. Then, integrated soil health indexes (SHI) were calculated using the SMAF algorithms. Briefly, DE reduced (0.44 and 0.47 in rainy and dry seasons, respectively) the SHI compared to NV (0.72 and 0.82 in rainy and dry seasons, respectively). Importantly, RE recovered SH after two decades of implantation (0.65 and 0.79 in rainy and dry seasons, respectively). Bulk soil density and SAR were the indicators that presented a higher negative correlation with SH, mainly in DE, while SOC, MBC, and β-glucosidase activity correlated with SH in NV and RE soils. Biological soil health indicators increased in dry season, which may be due to the deciduous behavior of Caatinga vegetation, which could intensify microbial activity. We provided novel evidence that SMAF can be a user-friendly tool to monitor changes in SH under Brazilian drylands soils. In addition, long-term grazing exclusion can restore SH, contributing to curbing the desertification process in the region. © 2023 Elsevier B.V.