Brazilian subtropical grasslands present generally low yield and quality due to low soil fertility and, as their forage production is concentrated on the spring and summer period, present a winter feed gap problem for producers. To overcome this feed gap, producers can intercrop their subtropical native pastures with winter active grasses. In order to establish the optimal P application rate for subtropical grassland intercropped with winter active grasses (oats - Avena sativa L.) and Italian ryegrass (Lolium multiflorum Lam.), five rates of P were applied (0, 45, 90, 180 and 360 kg ha-1 P2O5), in autumn 2010. The yield and quality (nutritional values of forage and mycorrhizal colonization of the roots of the winter active grasses) and botanical composition of the forage were monitored for 4.5 years. Grassland and winter forage yields increased average 2.6- and 6.0-fold, respectively, decreasing seasonality of feed supply. Phosphorus application increased concentrations of P, K, Ca, Mg and Cu in the winter active grasses. Conversely, only a small increase in P concentration was observed in the native, summer active grasses. Mycorrhizal colonization of the winter active grasses was sensitive to P application, reducing from 90 and 50% at control, to 50 and 15% at highest phosphorus rate, for oats and ryegrass, respectively. The phosphate fertilization affected species composition of the pasture, decreasing the number of species, but, did not compromised the ecological diversity index (Shannon-Wiener (H’), Simpson diversity and the Pielou equitability (J') indices). The capacity of Mehlich-1 extractor to predict soil P availability was discussed.
As frutas cítricas possuem grande destaque para o agronegócio nacional, encontrando no Brasil, condições ecológicas mais favoráveis em comparação ao seu local de origem, para se desenvolver vegetativamente e em produção, e com isso, pode-se espalhar seus plantios em todo o território nacional, inclusive na região Norte do país como o Estado do Pará. O objetivo deste trabalho foi avaliar o desempenho precoce de diferentes porta-enxertos com limão ‘Tahiti’ no município de Capitão Poço, Pará. O delineamento experimental utilizado foi blocos casualizados, quatro repetições e 10 plantas por parcela. Avaliaram-se as características: PF: peso total dos frutos, em kilograma; DAM: diâmetro 5 cm acima da cicatriz de enxertia, em centímetros; DDC: diâmetro 5 cm abaixo da cicatriz de enxertia, em centímetros. As análises empregadas foram gráficas AMMI e GGE Biplot obtendo-se como principais conclusões de que o melhor desempenho associando estabilidade em AMMI, no caso a combinação B10, não foi superior em GGE Biplot, pois na verdade pouco contribuiu positivamente para as médias e; na AMMI B8 e B10 em PF, B8 e B7 em DAC e DDC, são de maiores contribuições para as médias, contudo pecam pela estabilidade, enquanto em GGE Biplot foram considerados os superiores.
Abstract: Whether gypsum application changes mineral composition of Eucalyptus urograndis bark and wood along a tree height gradient is uncertain. Therefore, an experiment was established to examine three rates of broadcasted gypsum (1.2, 4.8, and 9.6 Mg ha-1; control); applied before planting. Three years after application, discs were collected to obtain bark and wood chemical composition from the tree base and at 25, 50, 75, and 100% of total height. Results shows that calcium (Ca), iron (Fe), aluminum (Al), and manganese (Mn) can accumulate in wood at the tree base, while potassium (K), sulfur (S), and phosphorus (P) tend to accumulate in the upper portions of trees. Gypsum application increased concentrations of Ca, S, and P in wood; Ca, S, P and copper (Cu) in bark; and decreased Mn in bark and wood. Findings suggest that high gypsum rates increased exportation of Ca, S and P by wood. Additionally, to accurately estimate nutrient exportation it is important to sample at multiple height positions along the tree trunk.
Silviculture using species of the genus Eucalyptus L’Heritier in Brazil, is a highly technological and specialized activity, predominating the intensive system through clonal plantations for the cellulose fibre export market. The aim of this study is to evaluate the development of the productive and extensive arrangement of Eucalyptus L’Heritier silviculture distributed throughout Northeast Brazil. We obtained data from the official platform of the Brazilian Institute of Geography and Statistics (IBGE) on the number of municipalities, inhabitants, territorial extension of municipalities, and states in Northeast Brazil and data on planted areas and wood production volume, as well as for the monetary value of Eucalyptus L’Heritier silviculture production in Northeast Brazil for the year 2022. We compiled the data spreadsheet and conducted descriptive statistics, generating self-explanatory graphs and tables, using JASP 0.18® software. Using vector cartography in SHP format of the year 2022 obtained from the IBGE platform, for municipal and state territories in the Northeast region of Brazil, we created, a thematic map of the distribution of Eucalyptus L’Heritier plantations in these territories with the aid of QGIS® 3.28 software. We observed that only 10 municipalities represent approximately 60% of the planted areas in each state. Maranhão and Bahia had the highest cellulose and charcoal production and the greatest number of municipalities and planted areas. Eucalyptus L’Heritier silviculture in the Northeast has a positive regional socioeconomic impact by providing a clean energy matrix and the possibility of cultivation in small rural properties, outside large production centres.
Uma grande área de cultivo de mandioca (Manihot esculenta Crantz), no Rio Grande do Sul, ocorre em solos argilosos e úmidos ocasionando elevadas perdas por podridões radiculares. O objetivo deste trabalho foi de avaliar a eficácia da inoculação das manivas-semente, da cultivar ‘Polpa Amarela’, com Trichoderma asperellum, no controle de podridões radiculares, no processo de tuberização e no tempo de cozimento das raízes. O experimento foi conduzido em vasos enterrados, com volume de 20 L de solo, sendo as manivas inoculadas na concentração de 1 x 107 esporos mL-1 e acondicionadas, verticalmente, uma unidade em cada vaso. Até o quinto mês após o plantio (MAP) foram realizadas análises mensais, sendo a avaliação final conduzida aos oito MAP. No segundo MAP somente raízes fibrosas foram observadas em plantas de ambos os tratamentos. Entretanto, no terceiro MAP, o teste do iodo-amido evidenciou tuberização em raízes com 5 mm de diâmetro, em plantas de ambos os tratamentos. Na avaliação final, aos oito MAP, não houve diferença no rendimento e na ocorrência de podridões radiculares. A inoculação, também, não afetou o grau de aderência da casca e o tempo de cozimento que foi de 19 e 21 min para raízes de plantas inoculadas e controle, respectivamente. Pode-se concluir, portanto, que o processo de tuberização, da cultivar de mandioca ‘Polpa Amarela’, tornou-se perceptível aos três MAP e que a inoculação com Trichoderma asperellum não teve influência na ocorrência de podridões e no rendimento de raízes tuberosas.
