Adubação fosfatada no crescimento inicial de sete espécies florestais nativas destinadas à recuperação de uma área degradada

For an effective forest restoration, knowledge about the initial growth of plants is of fundamental importance. Among the aspects to be considered, the nutritional requirements of the species used for this purpose stand out, considering that these areas generally have low fertility soils, which can hinder the establishment and growth of the planted species. The objective of this work was to evaluate the influence of phosphate fertilization on native forest species, destined to the recovery of a degraded area. The experiment was carried out at the Center for Scientific and Technological Development at UFLA - Fazenda Muquém, located in the municipality of Lavras, Minas Gerais. The experimental design used was in complete randomized blocks, with 12 replicates and one plant per plot, in a 7 x 4 factorial scheme, with seven species and four doses of simple superphosphate (0, 150, 300 and 450 grams/pit). At 60 days after planting, data on percentage of survival, diameter at ground level and plant height were collected. At 300 days, in addition to the diameter and height, the canopy projection area of the plants was evaluated. The species showed high percentages of survival, with the exception of Inga edulis, with 58% survival. Among the seven species studied, Schinus terebinthifolius and Guazuma ulmifolia were the ones that showed the highest growth in the analyzed parameters, being, therefore, the species with the greatest potential for a faster covering of this area. Phosphate fertilization influenced, in a different way, the initial growth of the seven species, in relation to the doses of simple superphosphate applied. It is recommended to dose 250 grams of simple superphosphate per hole, as a basic fertilization for all species.Para que haja uma restauração florestal eficaz é de fundamental importância o conhecimento sobre o crescimento inicial das plantas. Dentre os aspectos a serem considerados destacam-se as exigências nutricionais das espécies utilizadas para tal finalidade, tendo em vista que essas áreas, geralmente, apresentam solos de baixa fertilidade, o que pode dificultar o estabelecimento e crescimento das espécies plantadas. O objetivo deste trabalho foi avaliar a influência da adubação fosfatada em espécies florestais nativas, destinadas à recuperação de uma área degradada. O experimento foi conduzido no Centro de Desenvolvimento Científico e Tecnológico da UFLA - Fazenda Muquém, situada no município de Lavras, Minas Gerais. O delineamento experimental utilizado foi em blocos casualizados completos, com 12 repetições e uma planta por parcela, em esquema fatorial 7 x 4, sendo sete espécies e quatro doses de superfosfato simples (0, 150, 300 e 450 gramas/cova). Aos 60 dias após o plantio, foram coletados dados sobre porcentagem de sobrevivência, diâmetro ao nível do solo e altura das plantas. Aos 300 dias, além do diâmetro e altura, foi avaliada a área de projeção de copa das plantas. As espécies apresentaram altos percentuais de sobrevivência, com exceção do Inga edulis, com sobrevivência de 58%. Dentre as sete espécies estudadas, Schinus terebinthifolius e Guazuma ulmifolia foram as que apresentaram maior crescimento dos parâmetros analisados, sendo, portanto, as espécies de maior potencial para um recobrimento mais rápido dessa área. A adubação fosfatada influenciou, de forma distinta, o crescimento inicial das sete espécies, em relação às doses de superfosfato simples aplicadas. Recomenda-se a dose de 250 gramas de superfosfato simples por cova, como adubação de base para todas as espécies

Influence of Molybdenum doses in inoculation and mineral fertilization in cowpea beans

In some leguminous plants, associations with nitrogen-fixing microorganisms allow their nutrition with nitrogen (N) from the atmosphere. This process is known as Biological Nitrogen Fixation (BNF), where through nitrogenase enzymes, N2 is converted to an available form. This process can replace in part, or in total, nitrogen fertilizers. Cowpea bean is a legume species that is recognized for its high capacity to carry out BNF. In the last decades, studies have encouraged small farmers from north and northeast Brazil to use inoculants with rhizobia species since the results of researches have demonstrated that inoculation is an interesting strategy to improve cowpea production. Considering the specific function of molybdenum (Mo) in the N assimilation, different doses of Mo were tested in this study in order to find doses that could improve and enhance BNF. Therefore, this study aimed to compare nitrogen fertilization and BNF in the N assimilation by plants with different Mo doses. Inoculation was performed with the strains UFLA 03-84 and INPA 03-11B. Doses of Mo were applied in seeds and each pot contained five seeds. Thirty-five days after germination, the plants were analyzed for shoot dry matter and fresh matter, N contents and accumulation, as well as the Soil-Plant Analysis Development (SPAD) Index and nodulation in inoculated plants. The different doses of Mo and also the nodulation treatments did not show significant differences in the contents of N. Plants with N fertilization had significant higher shoot dry matter and root dry matter production, in addition to higher N foliar contents and N accumulation. Therefore, BNF was not as efficient as nitrogen fertilization in the evaluated experimental conditions using cowpea beans