Characterization and detailed mapping of C by spectral sensor for soils of the Western Plateau of São Paulo.

Soil mineralogy and texture are directly related to soil carbon due to the physical properties of the clay surface. Traditional techniques for quantifying carbon in soil are time-consuming and expensive, making large-scale quantification for mapping unfeasible. The alternative is the use of soil sensors, such as diffuse reflectance spectroscopy (DRS), an economical, fast, and accurate technique for predicting carbon stocks. In this sense, this study aimed to (a) investigate the relationship of C with different soil mineralogical, chemical, and physical attributes for different geological and geomorphological compartments; (b) understand which spectral bands are most important for estimating C content; (c) estimate C content from diffuse reflectance spectroscopy using different mathematical techniques and indicate which one is the best for tropical soil conditions; and (d) map C contents in detail. The study area was the Western Plateau of São Paulo (WPSP), which covers approximately 13 million hectares (~ 48% of the State of São Paulo, Brazil). A total of 265 samples were collected in this area. The attributes clay, silt, sand, crystalline and non-crystalline iron, base saturation, soil density, total pore volume, total C, C stock, kaolinite/(kaolinite + gibbsite) and hematite/(hematite + goethite), hematite and goethite contents, and spectral curves were evaluated. The spectra were recorded at 0.5-nm intervals, with an integration time of 2.43 nm s-1 over the 350 to 2500-nm range (350-800 nm-visible-VIS and 801-2500 nm-near-infrared-NIR). The data were subjected to descriptive statistics, Spearman correlation, stepwise analysis, and cluster grouping for characterization purposes; partial least squares regression (PLSR) and random forest (RF) for estimation purposes; and geostatistics analysis for creation of spatial maps. Our results indicate that the highest C contents are associated with more clayey soils, oxidic mineralogy, higher total pore volume, and lower soil density in highly dissected basalt compartments. The random forest algorithm associated with the Vis-NIR spectral range is more efficient for estimating and mapping C contents. This suggests that integrating diffuse reflectance spectroscopy with machine learning techniques holds promise for shaping public policies related to land use, mitigating CO2 emissions, and facilitating the implementation of carbon credit policies in a rapid and economically efficient manner.

Implications of converting native forest areas to agricultural systems on the dynamics of CO2 emission and carbon stock in a Cerrado soil, Brazil.

The conversion of native vegetation to agricultural areas leads to a natural process of carbon loss but these systems can stabilize in terms of carbon dynamics depending on the management and conversion time, presenting potential to both store and stabilize this carbon in the soil, resulting in lower soil respiration rates. In this context, this study aimed to investigate the effect of converting native Cerrado forest areas to agricultural systems with a forest planted with Eucalyptus camaldulensis and silvopastoral systems on the dynamics of CO2 emission and carbon stock at different soil depths. The experimental sites are located in the Midwest of Brazil, in the coordinates 20°22'31″ S and 51°24'12″ W. Were evaluated soil CO2 emission (FCO2), soil organic carbon, the degree of humification of soil organic matter (HLIFS), soil temperature, soil moisture, and soil chemical and physical attributes. The soil of the area is classified as an Oxisol (Haplic Acrustox). Soil samples were collected at depths of 0.00-0.10, 0.10-0.20, 0.20-0.30, and 0.30-0.40 m. The lowest FCO2 values were found in the silvopastoral system (1.05 µmol m-2 s-1), followed by the native forest (1.65 µmol m-2 s-1) and the eucalyptus system (1.96 µmol m-2 s-1), indicating a 36% reduction in FCO2 compared to the conversion of the native forest to the silvopastoral system and an increase of 19% when converting the native forest to the eucalyptus system. The soil chemical attributes (N, K+, Ca2+, H++Al3+, CEC, and organic carbon) showed a decrease along the profile. The shallowest depths (0.00-0.10 and 0.10-0.20 m) presented no differences between systems but the subsequent depths (0.20-0.30 and 0.30-0.40 m) had a difference (95% confidence interval), relative to N, Ca2+, H++Al3, CEC, and organic carbon stock (OCS), and the soil under silvopastoral system showed a higher concentration of these attributes than the native forest. The multivariate analysis showed that the eucalyptus and silvopastoral systems did not differ from the forest in the shallowest soil layer but differed from each other. This behavior changed from the second assessed depth (0.10-0.20 m), in which the silvopastoral system stands out, differing both from the eucalyptus system and from the native forest, and this behavior is maintained at the following depths (0.20-0.30 and 0.30-0.40 m). OCS, H++Al3, CEC, and nitrogen are strongly related to land use change for silvopastoral system. Regarding the behavior/relationship of attributes as a function of depth, the silvopastoral system contributed to soil carbon accumulation and stability over consecutive years.

Psychosocial impacts of the COVID-19 pandemic among settled women: A longitudinal study / Os impactos psicossociais da pandemia de COVID-19 entre mulheres assentadas: estudo longitudinal / Impactos psicosociales de la pandemia de COVID-19 en mujeres de asentamientos rurales: estudio longitudinal

Abstract Objective: to analyze the psychosocial impacts of the COVID-19 pandemic among Brazilian women from rural settlements. Method: this is a quantitative and longitudinal study conducted with 13 settled women. The data were collected between January 2020 and September 2021 using questionnaires on the perception of the social environment (quality of life, social support, self-efficacy), common mental disorder symptoms and sociodemographic aspects. The data were analyzed using descriptive statistics, cluster analysis and variance analysis. Results: intersecting vulnerability conditions were identified that possibly intensified the challenges arising from the pandemic. The Quality of Life physical domain fluctuated differently and inversely according to the mental disorder symptoms. As for the psychological domain, at the end of the segment, an increase over time was identified in the entire sample, as the women's perception was better than before the pandemic. Conclusion: worsening of the participants' physical health deserves to be highlighted and, probably, it can be related to the difficulty accessing health services in this period as well as to the fear of contamination. Despite this, the participants were emotionally resilient throughout the period, including signs of improvement in terms of psychological aspects, suggesting a possible effect of the community organization of the settlement.

Resumo Objetivo: analisar os impactos psicossociais da pandemia de COVID-19 entre mulheres brasileiras de assentamentos rurais. Método: trata-se de um estudo quantitativo longitudinal com 13 mulheres assentadas. Os dados foram coletados entre janeiro de 2020 e setembro de 2021 utilizando questionários sobre a percepção do ambiente social (qualidade de vida, apoio social, autoeficácia), sintomas de transtorno mental comum e aspectos sociodemográficos. Os dados foram analisados por meio de estatística descritiva, análise de agrupamento e de variância. Resultados: foram identificadas condições de vulnerabilidade interseccionadas que, possivelmente, exacerbaram os desafios decorrentes da pandemia. O domínio físico da qualidade de vida oscilou diferentemente e inversamente de acordo com os sintomas de transtorno mental. Quanto ao domínio psicológico, no final do segmento, identificou-se em toda a amostra um incremento ao longo do tempo, pois a percepção das mulheres estava melhor do que antes da pandemia. Conclusão: a piora na saúde física das participantes merece destaque e, provavelmente, pode estar relacionada à dificuldade de acesso aos serviços de saúde neste período bem como ao medo da contaminação. Apesar disso, as participantes apresentaram-se emocionalmente resilientes em todo o período, inclusive, com sinais de melhora em relação aos aspectos psicológicos, sugerindo um possível efeito da organização comunitária do assentamento.

Resumen Objetivo: analizar los impactos psicosociales de la pandemia de COVID-19 en mujeres brasileñas de asentamientos rurales. Método: se trata de un estudio longitudinal cuantitativo con 13 mujeres asentadas. Los datos se recolectaron entre enero de 2020 y septiembre de 2021 mediante cuestionarios sobre percepción del entorno social (calidad de vida, apoyo social, autoeficacia), síntomas de trastorno mental común y aspectos sociodemográficos. Los datos se analizaron mediante estadística descriptiva, análisis de conglomerados y análisis de varianza. Resultados: se identificaron condiciones de vulnerabilidad entrelazadas que posiblemente exacerbaron los desafíos impuestos por la pandemia. El dominio físico de la calidad de vida fluctuó de manera diferente e inversa de acuerdo a los síntomas del trastorno mental. En cuanto al dominio psicológico, al final del segmento, se identificó un aumento en el tiempo en toda la muestra, dado que la percepción de las mujeres era mejor que antes de la pandemia. Conclusión: hay que destacar el empeoramiento de la salud física de las participantes que, probablemente, puede estar relacionado con la dificultad para acceder a los servicios de salud durante ese período y el miedo al contagio. A pesar de eso, las participantes fueron resilientes emocionalmente durante todo el período e, inclusive, tuvieron signos de mejoría en los aspectos psicológicos, lo que sugiere un posible efecto de la organización comunitaria del asentamiento.