ABSTRACT:Understanding the spatial variability of soil chemical and physical attributes is important for improving management practices and soil conservation. In turn, the spatial variability of soil properties results from variation in morphological relief characteristics. Thus, the purpose of this study was to evaluate the influence of landform curvature on the spatial variability of soil chemical and physical attributes in the Mar de Morros region (Pinheiral-Rio de Janeiro State, Brazil). Two adjacent landforms were selected with convex and concave curvature and sampled in a regularly spaced grid of 10 meters. A total of 56 soil samples (0-5 cm depth) from the two landforms were collected and analyzed for physical and chemical attributes. The data were analyzed using descriptive statistics and geostatistics. All chemical attributes showed random patterns of spatial variability in both landforms. The concave landform had higher values of pH and potassium and lower values of aluminum than the convex landform. In contrast, silt content showed spatial dependence in both the concave and convex landforms. Bulk density and clay showed spatial dependence in the convex landform. Bulk density and silt content increased from the shoulder to the footslope of both landforms. The results show that, for this study area, landform curvature has more influence on the spatial dependence of soil physical attributes than of soil chemical properties. CURVATURA DA SUPERFÍCIE E SEU EFEITO NA VARIABILIDADE ESPACIAL DOS ATRIBUTOS DO SOLO, PINHEIRAL -RJ / BRRESUMO: Compreender a variabilidade espacial dos atributos químicos e físicos do solo é importante para melhorar as práticas de manejo e conservação do solo. Por sua vez, a variabilidade espacial das propriedades do solo resulta da variação das características morfológicas do relevo. Assim, o objetivo deste estudo foi avaliar a influência da curvatura da superfície na variabilidade espacial dos atributos químicos e físicos do solo na região de Mar de Morros (Pinheiral-Rio de Janeiro, Brasil). Foram selecionadas duas pedoformas adjacentes com curvatura convexa e côncava e coletadas amostras de solo em uma grade com espaçamento fixo de 10 metros entre os pontos. Foram coletadas um total de 56 amostras de solo (0-5 cm de profundidade) nas duas pedoformas e analisados os atributos físicos e químicos do solo. Na análise dos dados foi utilizada estatística descritiva e geoestatísitca. Os atributos químicos do solo apresentaram um padrão aleatório quanto a distribuição espacial em ambas as pedoformas. No entanto, a pedoforma côncava apresentou maiores valores de pH e potássio e valores mais baixos para alumínio quando comparada a pedoforma convexa. Por outro lado, os valores de silte apresentaram dependência espacial em ambas às pedoformas. Já a densidade do solo e o teor de argila apresentaram dependência espacial na pedoforma convexa. Os valores da densidade do solo e silte aumentaram no sentido do terço superior para o terço inferior em ambas as pedoformas. Os resultados mostram que par...

RESUMOA composição e qualidade do banco de sementes são alguns dos fatores responsáveis pela estrutura e composição florística dos ambientes florestais. O objetivo deste estudo foi avaliar o banco de sementes de um fragmento de Floresta Estacional Semidecidual, com influência das características topográficas da paisagem. Foram selecionadas duas pedoformas adjacentes com relevo do tipo convexa e côncava, sendo essas divididas em minissítios (MS) I, II, e III na pedoforma convexa, e IV, V, VI na pedoforma côncava. Foram amostrados 10 pontos de cada MS, distribuídos assistematicamente, com uma área superficial de 0,0625 m² e profundidade de 3 cm. Foi registrado um total de 4.862 sementes.m -1 germinadas no período de 90 dias, sendo na pedoforma convexa observado o maior número de sementes.m -1 germinadas. Em ambas as pedoformas, foram identificadas 35 famílias e 88 espécies; dentre as espécies, 37% têm hábito herbáceo; 24%, arbóreo; 18%, arbustivo; 12%, trepador; e 2%, epifítico. Quanto ao tipo de pedoforma, foram registradas 44% das espécies encontradas em ambas, 31% foram exclusivas da convexa e 25%, da côncava. Para aos parâmetros florísticos e fitossociológicos, a pedoforma convexa apresentou maior número de sementes, famílias, espécies e riqueza, enquanto a côncava teve maiores índices de diversidade. As condições topográficas foram determinantes na composição florística e fitossociológica do banco de sementes, sendo os maiores valores de riqueza verificados na pedoforma convexa e de diversidade, na côncava, com maior índice de valor de importância para as famílias Asteraceae, Melastomataceae e Urticaceae. Palavras-chave: Floresta Atlântica; relevo; fragmentos florestais. ABSTRACTThe composition and quality of the seed bank are some of the factors responsible for the structure and floristic composition of forest environments. The aim of this study was to evaluate the seed bank of a semideciduous forest patch, taking into account the influence of the landscape's topographical features. Two adjacent landforms, of convex and concave shapes, were selected. They were divided into mini sites

Relief is a soil formation factor that can modify the distribution of soil organic matter (SOM) fractions in a landscape. The objective of this study was to evaluate the effect of the relief on SOM fractions, considering their distribution in different topographic positions, segments, in two pedoforms (concave and convex) in areas covered with forest in the Atlantic Forest biome. The two pedoforms were selected in adjacent areas and divided into segments considering the topographic variation. The carbon and nitrogen origins were evaluated in the extract up to 100 cm of depth. Soil samples from the 0-5, 5-10, and 10-20 cm layers were collected for chemical characterization and fractioning (granulometric and chemical) of the SOM. The soil density in the 0-5 and 5-10 cm layers was determined to calculated the carbon stocks. The isotopic composition showed predominance of 13C. The highest organic carbon and particulate carbon contents were found in the convex pedoform. The distribution of humic fractions showed that the larger part of the humidified carbon was in the humin fraction. The humin and fulvic acid fractions were higher in the convex pedoform. The carbon stocks were, in general, higher in the convex pedoform, decreasing as the soil depth increased; and nitrogen stocks presented no differences. The higher carbon and nitrogen contents were found in the convex pedoform and in the lower region of the concave pedoform.

Soil organic matter (SOM) and the chemical attributes of the soil are important indicators of soil quality. The aim of this study was to evaluate the effects of strategies for controlling spontaneous plants on SOM quality and soil fertility in an area of forest under restoration. Three methods for controlling spontaneous plants were established: i) mechanical (MCH), ii) chemical (CHM), and iii) chemical-cultural (CC), and evaluated using a randomized block design. After 13 months, soil samples were collected (0-10 cm) to determine basal respiration over 21 days, total organic carbon (TOC), labile carbon (LC), chemical fractions of the SOM [humine (H), humic acid (HA) and fulvic acid (FA)], and soil fertility. On days 1, 3, and 7, higher values were seen for basal soil respiration, however, no differences were found between the control strategies. There was a small change in SOM quality and soil fertility. MCH showed higher values (up to 11%) for LC, due to the intense silvicultural management. After 13 months of application, each of the strategies for controlling spontaneous vegetation proved to be favorable in relation to SOM quality and soil fertility, especially for LC, due to its relationship with the accumulation or loss of SOM, and immediate response to changes in land use or management.

Urban organic waste has been gaining prominence in the composition of substrates, as it is a source of natural nutrients and a sustainable alternative to mitigate environmental impacts caused by improper waste disposal. The aim of this study was to characterize chemically and physically substrates based on organic waste and to evaluate the development of Colubrina glandulosa seedlings using composted urban tree pruning waste. Treatments consisted of different proportions of organic compost (CP), soil from the A horizon (SAH), aged manure (BM) and vermiculite, kept in tubes (Citropote®) with volume of 1.7 L. C/N ratio, water holding capacity (10 hPa), electrical conductivity, macroporosity, microporosity and total porosity of substrates before their use were determined. Substrate fertility analyses were carried out before and after seedling production. During the development of the seedlings, height (H) and stem diameter (SD) were measured at 60, 90 and 120 days. At 90 and 120 days, the seedlings were divided into shoots and roots to determine the dry mass of each compartment, Dickson quality index (DQI) and contents of nutrients (N, P, K, Ca and Mg). After the analysis of the results, it can be observed that the treatments with high proportions of CP had better physical characteristics, but also showed chemical limitation in the development of the seedlings. Treatments based on BM, SAH and lower proportion of CP had the highest average results for H, SD, H/SD ratio and DQI.