INITIAL GROWTH OF Citharexyllum myrianthum plants UNDER PLANTING FERTILIZATION

The objective of this work was to evaluate the initial growth of Citharexyllum myrianthum under the influence of three sources of planting fertilizers, in conditions of 18 L pots. The treatments used were, as follows: absolute control; 5 L of biosolid/pot; 300 g of natural rock phosphate (NRP), and 200 grams of NPK 06-29-06. The seedlings were grown in pots in full sun, supplemented with Dystrophic Red Yellow Latosol. At 150 days after transplanting, the plants were measured, obtaining the height of the aerial part and the diameter of the stem. Then, the increment of these two variables was calculated. Subsequently, the leaves were removed to determine the leaf area (LA), separating the aerial part from the root system, and then packed in a paper bag and placed in an oven at 65ºC, for drying until reaching constant weight. After weighing this material to obtain the dry matter of the aerial part (APDM) and root (RDM). The leaves were ground to determine the foliar contents of N, P, K, Ca, and Mg. To evaluate the effect of treatments on the soil, samples were taken from the pots to determine the levels of macronutrients, organic matter, and CEC(t). It was found that the LA and APDM of plants fertilized with NPK showed significantly higher values when compared to plants cultivated in the control treatment. It is recommended to fertilize Citharexyllum myrianthum plants with 200 grams of N-P-K 06-29-06/hole or with 5 L of biosolid

PHYSICAL, CHEMICAL, AND BIOLOGICAL SOIL ATTRIBUTES UNDER ANALOG AGROFORESTRY SYSTEM AND PASTURE SITES

Analog agroforestry system uses native tree species to improve soil conditions and the microclimate of degraded areas. This study aimed to assess the impact of analog agroforestry on physical, chemical, and biological soil attributes. We tested the hypothesis that some of these attributes can be used as indicators of soil quality improvement compared to a managed pasture area. Two experimental sites were selected, an analog agroforestry site and a pasture site. In October 2016 (end of the dry season), soil samples were collected from the 0–5 and 5–10 cm depths and the soil fauna community was sampled using pitfall traps. The analog agroforestry system led to increased total abundance, total richness, mean richness, evenness, and diversity of the soil fauna community as well as higher gravimetric soil moisture, sand content, pH, calcium, magnesium, and sum of exchangeable bases, which are good indicators of soil quality. Adults of Coleoptera, Diptera, Gastropoda, Hymenoptera, Isopoda, Lepidoptera, Poduromorpha, Symphypleona, Pseudoscorpionida, Lepidoptera and larvae of Coleoptera, Diptera, Lepidoptera, and Neuroptera were the most abundant taxonomic groups in the analog agroforestry system

Ciclagem de nutrientes em diferentes condições topográficas em Floresta Estacional Semidecidual, Pinheiral-RJ

In forest ecosystems the dynamics of burlap is related to the plant typology and to the climatic conditions of environments, which are influenced by the topographic heterogeneity of the landscape. The objective of this study was to evaluate whether different relief conditions (convex and concave pedoforms) alter the burlap dynamics in a semi-deciduous seasonal forest in the sub-basin of Cachimbal, Pinheiral – RJ state. Two adjacent landforms with relief convex type (convex-divergent) and concave (concave-convergent) were selected, and these ones were divided into mini sites (MS) I, II, and III in the convex landform and IV, V and VI in the concave landform. The stock and the decomposition of the burlap in two seasons (rainy and dry) were rated in different environments. To evaluate the stock, ten samples of litter from each MS were collected using a square template with 25-cm side. To evaluate the burlap decomposition rate, 10 g of leaves were selected, which were placed in litterbags, installed in the field and collected at different time intervals. Litter stock and nutrient contents were influenced by the pedoform type, topographic gradient variation and season, larger stocks were observed in convex pedoform in dry season and higher K + and Mg + 2 contents. in the lower pedoform MS. On the other hand, the carbon contents were influenced only by the season of the year like higher contents in the rainy season. The decomposition of burlap forming material occurs differently depending on the landform, topographic gradient and on the season, where the highest values were observed in the convex landform and in the rainy season.Nos ecossistemas florestais, a dinâmica da serapilheira está relacionada à tipologia vegetal e as condições climáticas dos ambientes, as quais são influenciadas pela heterogeneidade topográfica da paisagem. Assim, o objetivo deste estudo foi avaliar se diferentes condições de relevo (pedoformas convexa e côncava) alteram a dinâmica da serapilheira em Floresta Estacional Semidecidual na sub-bacia do ribeirão Cachimbal, Pinheiral-RJ. Foram selecionadas duas pedoformas adjacentes com relevo do tipo convexa (convexa-divergente) e côncava (côncava-convergente), sendo essas divididas em minissítios (MS) I, II, e III na pedoforma convexa e IV, V e VI na pedoforma côncava. Nos diferentes ambientes foram avaliados o estoque e a decomposição da serapilheira em duas estações do ano (chuvosa e seca). Para avaliar o estoque foram coletadas dez amostras de serapilheira de cada um dos MS, utilizando um gabarito quadrado com 25 cm de lado. Para avaliar a taxa de decomposição da serapilheira, foram selecionadas 10 g de folhas, as quais foram acondicionadas em litterbags, instalados no campo e coletadas em diferentes intervalos de tempo. O estoque e os teores de nutrientes da serapilheira foram influenciados em função do tipo da pedoforma, variação do gradiente topográfico e estação do ano, maiores estoques foram observados na pedoforma convexa, em estação seca e os maiores teores de K+ e Mg+2 foram observados nos MS inferiores das pedoformas. Por outro lado, os teores de carbono foram influenciados apenas pela estação do ano como maiores teores na estação chuvosa. A decomposição da serapilheira ocorre de maneira diferenciada em função da pedoforma, do gradiente topográfico e da estação do ano, cujos maiores valores foram observados na pedoforma convexa e na estação chuvosa

Biogenic and physicogenic aggregates as indicators of quality in soils with sandy texture in areas of organic agriculture

ABSTRACT Sandy texture soils have a great expression in agricultural areas worldwide. In the Baixada Fluminense, soils with a sandy texture on the surface horizons are striking, and a good part of these areas is destined for producing vegetables using conventional cultivation methods. The sandy texture is one of the great challenges for agriculture due to the low water retention capacity provided to the soil, the rapid decomposition of organic matter, and the intense loss of nutrients by leaching. In these areas, the action of erosive processes is sometimes observed, whether water or wind erosion. The practices carried out in conventional agriculture can accentuate these processes. This study aimed to evaluate the influence of different soil management systems, with different vegetation covers, on the pathways of aggregate formation, the nutrient contents contained therein, and the organic matter fractions, with the objective of using these properties as indicators of soil quality. The study was carried out in an organic production unit, with no-till system (NT) and conventional system (CT), three vegetal covers were evaluated, namely; seed cocktail 1 (C1) (Crotalaria (Crotalaria juncea) (20 kg ha-1), Jack Bean (Canavalia ensiformis) (150 kg ha-1) and millet (Pennisetum glaucum) (60 kg ha-1)), and seed cocktail 2 (C2) (with 50 % of the amount of seeds used in C1), and spontaneous plants (S. P). Undisturbed samples were collected at the layers of 0.00-0.05 and 0.05-0.10 m, and, from these samples, aggregates with a diameter between 9.7 and 8.0 mm were classified according to the formation route (Biogenic or Physicogenic). From these, the chemical properties were quantified (pH, Ca2+, Mg2+, Al3+, P, Na+, K+), and also the carbon fractions (total organic carbon – TOC, mineral-associated organic carbon – MAOC), particulate organic carbon – POC, and free light fraction carbon – LFC). Based on the results, it was verified that the percentage of biogenic aggregates was higher than the physicogenic one in the layer of 0.00-0.05 m, not being verified influences of the vegetal coverage or the management system. Chemical properties did not differ significantly between training pathways. The CT, for the most part, was the system in which the highest values of chemical properties were observed, and in general, the C2 and S.P coatings were the ones that provided the greatest improvements for chemical properties and carbon content

LANDFORM CURVATURE AND ITS EFFECT ON THE SPATIAL VARIABILITY OF SOIL ATTRIBUTES, PINHEIRAL-RJ/BR

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

Soil Physical and Chemical Properties in Epigeal Termite Mounds in Pastures

<div><p>ABSTRACT We characterized soil physical and chemical properties and soil organic matter in epigeal termite mounds in pastures to evaluate the changes promoted by termites in comparison to an adjacent area. We selected seven active epigeal termite mounds in the municipality of Seropédica, state of Rio de Janeiro, Brazil. Soil samples were collected from top, center and base positions of each mound, at 0.50 and 1.50 m distance from the base of the mound. We identified individuals of the genus Embiratermes, Velocitermes, and Orthognathotermes. The humin fraction predominated over the humic and fulvic acid fractions both in mounds and adjacent soil. The amount of organic matter and the mineral fractions (mineral-associated organic carbon - MOC) varied among builder species. The studied chemical attributes point to a higher concentration of nutrients in the mounds than in the adjacent soil.</p></div

Effects of Natural Atlantic Forest Regeneration on Soil Fauna, Brazil

<div><p>Abstract The stage of natural forest regeneration may influence soil fauna. This study aimed to test the hypothesis that there are differences in the structure and composition of the soil fauna communities between areas undergoing less advanced (LAS) and more advanced (MAS) stages of natural regeneration of Seasonal Semideciduous Forest at Pinheiral, RJ. Soil fauna was sampled using pitfall traps, during dry and rainy seasons. Total abundance, abundance of the saprophagous/predator group, mainly Formicidae, and the relative participation of Orthoptera were higher in MAS, while the relative participation of Acari, Araneae, Coleoptera, Diptera and the herbivorous group were higher in LAS, during both climatic seasons. Some taxonomic groups were restricted to one of the areas. Richness, evenness and diversity tended to present higher values in LAS (dry season). The higher complexity of the soil fauna community was correlated to the higher leaf litter standing stock in LAS.</p></div

Physical Attributes of an Irrigated Oxisol after Brassicas Crops under No-Tillage System

In no-tillage areas, cover crops are a continuous supply of organic matter and other positive improvements to the soil&rsquo;s structural quality. We evaluated soil physical attributes in area cultivated with brassica crops on residues of cover crops cultivated under no-tillage. Six cover crops coverages [1-Brachiaria (B), 2-Sunn hemp (S), 3-Pearl millet (M), 4-S + B; 5-B + M; 6-S + M] and a native area (Cerrado biome), were evaluated for soil resistance to penetration (RP), soil density (SD), soil macroporosity, microporosity, volumetric moisture (VM), weighted mean diameter, geometric mean diameter, and aggregate stability index. RP and VM differed among treatments; no compacted soil layer was observed at up to 0.4 m soil depth; Low RP and SD were observed for Brachiaria and Pearl millet (Poaceae) compared to Sunn hemp (Fabaceae) in deeper soil layers; The principal components and cluster analysis indicated B + M as the most promising coverage for deep soil structuring. The soil physical quality indicators showed that millet in isolated cultivation or intercropped with another cover was the culture that presented the best results for most of the evaluated characteristics. The best indices of soil aggregation were observed where the species of the Poaceae Family were being cultivated in isolation or intercropped with each other