The riparian buffer width on watersheds has been modified over the last decades. The human settlements heavily used and have significantly altered those areas, for farming, urbanization, recreation and other functions. In order to protect freshwater ecosystems, riparian areas have recently assumed world recognition and considered valuable areas for the conservation of nature and biodiversity, protected by forest laws and policies as permanent preservation areas. The objective of this work was to compare parameters from riparian areas related to a natural watercourse less than 10 m wide, for specific purposes in Law No. 4761/65, now revoked and replaced by Law No. 12651/12, known as the New Forest Code. The effects of 15, 30 and 50 m wide riparian forest in water and soil of three headwater catchments used for sugar cane production were analyzed. The catchments are located in the Environmental Protection Area of Uberaba River Basin (state of Minas Gerais, Brazil), legally protected for conservation of water resources and native vegetation. A field survey was carried out in the catchments for verification of land uses, while periodical campaigns were conducted for monthly water sampling and seasonal soil sampling within the studied riparian buffers. The physico-chemical parameters of water were handled by ANOVA (Tukey’s mean test) for recognition of differences among catchments, while thematic maps were elaborated in a geographic information system for illustration purposes. The results suggested that the 10, 30 or even 50 m wide riparian buffers are not able to fulfill the environmental function of preserving water resources, and therefore are incapable to ensure the well-being of human populations. Therefore, the limits imposed by the actual Brazilian Forest Code should be enlarged substantially.

Global climate change is closely tied to CO₂ emissions, and implementing conservation-agricultural systems can help mitigate emissions in the Amazon. By maintaining forest cover and integrating sustainable agricultural practices in pasture, these systems help mitigate climate change and preserve the carbon stocks in Amazon forest soils. In addition, these systems improve soil health, microclimate regulation, and promote sustainable agricultural practices in the Amazon region. This study aimed to evaluate the CO₂ emission dynamics and its relationship with soil attributes under different uses in the Amazon. The experiment consisted of four treatments (Degraded Pasture—DP; Managed Pasture—MP; Native Forest—NF; and Livestock Forest Integration—LF), with 25 replications. Soil CO₂ emission (FCO₂), soil temperature, and soil moisture were evaluated over a period of 114 days, and the chemical, physical, and biological attributes of the soil were measured at the end of this period. The mean FCO₂ reached values of 4.44, 3.88, 3.80, and 3.14 µmol m⁻² s⁻¹ in DP, MP, NF, and LF, respectively. In addition to the direct relationship between soil CO₂ emissions and soil temperature for all land uses, soil bulk density indirectly influenced emissions in NF. The amount of humic acid induced the highest emission in DP. Soil organic carbon and carbon stock were higher in MP and LF. These values demonstrate that FCO₂ was influenced by the Amazon land uses and highlight LF as a low CO₂ emission system with a higher potential for carbon stock in the soil.

Considering the importance of nutrients in the soil for the plants development and the soil quality conservation and the quantification relevance of them for proper soil management, the aims of this research were: (i) to quantify the clay loss, adsorbed and soluble P from interrill erosion influenced by the presence of sugarcane residues on the ground surface; (ii) to determine the minimum percentage of residues to be maintained on the soil surface to not enrich the eroded sediment by clay and soluble P (Psed) and adsorbed (Pads). The experimental area is located in Guariba - SP, with soil classified as Red Dystrophic Oxisol. The experiment was designed based on results of previous experiments with residue analysis of variance for 40 plots. These experiments were conducted by our research group, which provided field representation and the establishment of a minimum number of degrees of freedom necessary to ensure normal distribution of results and variance homoscedasticity. The experimental design was completely randomized in a factorial design, 5 treatments with straw sugarcane and 3 repetitions, totaling 15 plots. In the treatments, the straw was manually distributed across the surface of the soil in amounts of 0; 0.16; 0.35; 0.52 to 0.7 Kg by plot, giving 0% coverage (SC0), 25% (SC25), 50% (SC50), 75% (SC75) and 100% (SC100), respectively. The experimental plots were subjected to simulated rain with average intensity of 60 mm h−1 for 65 minutes. To avoid enrichment ratio (ER) of the sediment eroded by Psed, Pads and clay, a minimum soil surface coverage (SC) of 42% is necessary.

A análise de um modelo de erosão é um crítico passo no desenvolvimento de uma ferramenta de predição da erosão aplicável e válida; isso é crucial para avaliar o desempenho dos modelos existentes para assegurar que as estimativas de um modelo condizem com a realidade. O objetivo do presente trabalho foi avaliar modelos para a predição do subfator cobertura e manejo (CiII) relativo à erosão entressulcos. Um experimento fatorial completo foi conduzido com cinco doses de resíduo de milho (0; 0,05; 0,15; 0,40 e 0,80 kg m-2), quatro declives e duas repetições, sob condições de prévio umedecimento para determinar as taxas de erosão entressulcos (Di) e enxurrada (R). Num primeiro experimento, foi avaliada a erodibilidade entressulcos (Ki) e o subfator cobertura e manejo (CiII), em parcelas experimentais de 0,5 x 0,75 m, em solo recentemente preparado. Num segundo experimento, foram avaliados Di, R, Ki e CiII, também em parcelas de 0,5 x 0,75 m, em solo recém- preparado. Os valores de Di, R, Ki e CiII, obtidos no segundo experimento, foram utilizados na avaliação dos modelos testados. Os modelos CiII = e-2,50 CS/100 e CiII = e -2,238 CS/100 apresentaram boas estimativas para o subfator CiII.

As Unidades de Conservação são um instrumento da Política Nacional de Meio Ambiente que determinou a criação de espaços para a proteção e a garantia do equilíbrio ecossistêmico no território brasileiro. A Área de Proteção Ambiental (APA) do rio Uberaba é uma Unidade de Conservação criada com o objetivo de garantir a qualidade das águas do rio Uberaba, sendo este o manancial de abastecimento público da cidade de Uberaba - MG. É caracterizada como uma unidade de conservação de uso sustentável, e algumas atividades altamente impactantes vêm sendo realizadas na sua área, com isso, causando diversas alterações no meio, tais como erosão, eutrofização de cursos d’água e alterações na qualidade e quantidade de água. O objetivo deste estudo foi estimar as perdas de solo e diagnosticar as áreas com potencial natural de erosão (PNE) utilizando a Equação Universal de Perda de Solo (EUPS), o Sistema de Informação Geográfica (SIG) e os produtos de sensoriamento remoto. O PNE apresentou valores baixos (1.000 t ha-1 ano-1) totalizaram 29,99% da APA. As estimativas de perda de solo pela erosão hídrica com valores abaixo de 5 t ha-1 ano-1 representam 43,81% da APA. Estimativas de perdas entre 5-10 t ha-1 ano-1 ocorrem em 12,22% da área, de 10-20 t ha-1 ano-1 em 21,82%, entre 20-50 t ha-1 ano-1 em 17,89%, 50-100 t ha-1 ano-1 em 3,92% e perdas superiores a 100 t ha-1 ano-1 em 0,34% da APA. O uso das geotecnologias e da Equação Universal de Perda de Solo possibilitou identificar espacialmente os locais em que ocorrem os maiores e os menores potenciais riscos de erosão, o que permitiu estimar as taxas de perda de solo ao longo da APA do rio Uberaba.

In recent decades, agricultural practices and urbanization, combined with inadequate conservation measures, have likely intensified soil erosion in the headwaters of the Córrego Rico watershed (HCRW), located in northeastern São Paulo State, Brazil. The HCRW represents an important water source for Jaboticabal and surrounding municipalities; however, it remains vulnerable to erosion driven by intensive agricultural use. This study aimed to estimate soil erosion and its spatial distribution in the HCRW using the Revised Universal Soil Loss Equation (RUSLE) integrated with a geographic information system (GIS). Spatial layers were developed in GIS for each RUSLE factor: average annual soil loss (A), rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover-management (C), and support practice (P). Estimated average annual soil loss (A) reached 68.61 t ha⁻1 year⁻1, with values ranging from 22.82 to 414.15 t ha⁻1 year⁻1. Approximately 77.40% of the watershed exceeded the tolerable soil loss limit of 8.6 t ha⁻1 year⁻1, indicating significant risks to soil productivity and ecosystem services, with potential implications for food and water security in the HCRW.