Edna Maria Bonfim-Silva

ESTABELECIMENTO DOS CAPINS XARAÉS E MARANDU SOB NÍVEIS DE COMPACTAÇÃO DO SOLO

In Cerrado soils under grazing, changes occur in physical attributes, such as increased density, decreasing on the size of water stable aggregates, and macroporosity reduction. Thus, the aim of this study was to study the effect of compaction on the establishment of two forages. It was adopted a completely randomized design with three replications, in 2 x 4 factorial design, and two forages (Xaraes grass and Marandu grass), and four levels of compaction (soil densities of 1.0, 1.2, 1.4, and 1.6 Mg m-3). The following variables were evaluated 48 days after sowing: tiller population, plant height, dry matter production of shoots and components, leaf and stem, as well as the root dry mass. The stem dry mass decreased with soil density in a similar manner for both forages. It was observed that the leaf dry mass and shoots dry mass of Xaraes grass remained constant in the levels of soil compaction, not adjusting to any regression model. The establishment of Xaraes grass has not been negatively affected by compaction, which may be suitable for situations where there may be layers that restrict the growth of different forages.

Nitrogen and potassium in production, nutrition and water use efficiency in wheat plants

Wheat ( Triticum aestivum L.) is a cereal used in food and feed for its nutritional properties. For nitrogen and potassium management, efficient use of water is required for greater availability and transportation of these nutrients. The objective of this study was to evaluate the effect of combinations of nitrogen and potassium doses in production, nutrition and water use efficiency in wheat. The experiment was held in a greenhouse with 8-dm3 pots using Oxisol collected at a depth of 0-0.2 m under Cerrado vegetation. Base saturation was raised to 60%. The experimental design was a randomized block in a 5x5 factorial arrangement with five doses of nitrogen (0, 100, 200, 300 and 400 mg dm-3) and potassium (0, 90, 180, 270, 360 mg dm-3) with four replications. Soil moisture was maintained by an auto-irrigation system (3 kPa pressure). The experiment was collected at 95 days after plant emergence. We evaluated the dry mass of ears, shoots and roots, the total dry matter, nitrogen and potassium in grains, and the consumption and efficiency in water use. An analysis of variance and regression test at 5% probability was conducted using SAS statistical software (SAS Institute, Inc., Cary, North Carolina). The nitrogen and potassium alone increased the dry mass of ears by 31.47% and 20.91%, respectively. There was an interaction of nutrients on the dry mass of the shoots and the total dry matter. Potassium increases the concentration of nitrogen. Nitrogen and potassium promote gains in production, nutrition and water use efficiency. Trigo ( Triticum aestivum L.) es un cereal utilizado en la alimentacion humana y animal por sus propiedades nutritivas. En la gestion de nitrogeno y potasio, el uso eficiente del agua es necesaria para la mayor disponibilidad y el transporte de estos nutrientes. Este estudio tuvo como objetivo evaluar el efecto de las combinaciones de nitrogeno y potasio en la produccion, la nutricion y la eficiencia en el uso del agua en trigo. El experimento se realizo en un invernadero con recipientes de 8 dm3. Usando Oxisol, recogido a una profundidad de 0-0,2 m de area bajo la vegetacion del Cerrado. La saturacion de bases se aumento a 60%. El diseno experimental fue de bloques al azar en arreglo factorial 5x5 con cinco dosis de nitrogeno (0, 100, 200, 300 y 400 mg dm-3) y potasio (0, 90, 180, 270 y 360 mg dm-3) con cuatro repeticiones. La humedad del suelo se mantuvo con un sistema autoirrigante (mantenido en el potencial de -3 kPa). El experimento foe cosecho despues de 95 dias de la emergencia. Se evaluaron la materia seca de las espigas, brotes, raices, y materia seca vegetal total; nitrogeno y potasio en granos; el consumo y la eficiencia en el uso del agua. Las variables se sometieron a analisis de varianza y prueba de regresion al 5% de probabilidad por el programa estadistico SAS. El nitrogeno y potasio, por separado, aumentaron el peso seco de las espigas, con incrementos de 31,47 y 20,91%, respectivamente. Hubo interaccion de nutrientes a la masa seca de la parte aerea y total. El potasio aumenta la concentracion de nitrogeno. El nitrogeno y el potasio promueven ganancias en la produccion, la nutricion y la eficiencia en el uso del agua.

NITROGÊNIO E POTÁSSIO EM CÁRTAMO: ÍNDICE DE CLOROFILA, CARACTERÍSTICAS BIOMÉTRICAS E USO DA ÁGUA

Safflower crops is usually intended for production of seeds to oil extraction. The objective of this work was to evaluate the chlorophyll index, biometric characteristics and water use efficiency of safflower plants grown under different nitrogen and potassium rates and controlled soil water tension. The experiment was conducted in a greenhouse, in pots containing 8 dm of a Oxisol. A complete randomized block experimental design in a 5x5 factorial arrangement was used, with four replications, consisting of five nitrogen rates (0, 60, 120, 180 and 240 mg dm) and five potassium rates (0, 50, 100, 150 and 200 mg dm). The safflower number of leaves, stem diameter, chlorophyll index, number of capitula, shoot, root and total dry weights, water consumption and water use efficiency were evaluated. Data were subjected to analysis of variance (F test) at 5% of probability and to polynomial regression. The nitrogen and potassium fertilization, as independent factors, affected the safflower plants. The chlorophyll index, biometric characteristics and water use efficiency of safflower showed better responses under nitrogen rates of 82 to 168 mg dm. The responses of chlorophyll index, biometric characteristics and water use efficiency of safflower increased 10 to 60% with potassium fertilization.

Combined inoculation of rhizobia on the cowpea development in the soil of Cerrado

BBiological nitrogen fixation (BNF) plays an important role in the cowpea cultivation. This study aimed to assess the foliar levels of chlorophyll and the yield components of cowpea subjected to combined inoculation of rhizobia in Cerrado soil. The experiment was carried out in field conditions, from December of 2014 to the march of 2015, in Rondonopolis, Mato Grosso, using randomized block design with ten treatments and three replicates. Were tested the single strains MT8 and MT15 (both of R. tropici), MT16 (R. leguminosarum), BR3267 (Bradyrhizobium japonicum), the strains combinations MT8+MT15, MT8+MT16, MT15+MT16, and MT8+MT15+MT16, nitrogen fertilization (70 kg ha-1 of N-urea), and absolute control (without inoculation of rhizobia and without nitrogen fertilization). Data were subjected to analysis of variance and the averages were compared by orthogonal contrast and F test (p≤0.05). Were assessed the Falker chlorophyll index (at the 40 and 60 days after sowing), number and dry matter of nodules (at the 40 days after sowing), number of pods per plant, grains yield, the concentration and accumulation of nitrogen in grains, and crude protein. The number of pods per plant was increased 33.6% in the combination MT8+MT15. The same effect was observed for the yield grain, which presented an increase of 8.7%, 13.8%, and 16.7% in the combinations MT8+MT16, MT15+MT16, and MT8+MT15, respectively. The nitrogen accumulation in the grains increased 42.7% with the inoculation of MT15 strain. The cowpea responds positively to the usage of combinations of rhizobia strains.

Características produtivas e nutricionais do capim-xaraés inoculado com bactérias diazotróficas associativas

The aim of this study was to evaluate yield and nutritional characteristics of Xaraes grass inoculated with diazotrophic associative bacteria in the first cultivation in the Cerrado Oxisol. The experiment was conducted in the greenhouse. The experimental design was completely randomized factorial 6x3 consisting of: three strains of diazotrophic associative bacteria (MTAz8, MTH2 and Y2), a combination of strains MTAz8 and MTH2, nitrogen fertilization and absolute control, and three cuts (30, 60 and 90 days) in five replicates. The inoculation was performed by inserting an aliquot of 5ml of the bacterial broth containing 108 cells ml-1 in the soil near the root zone of each plant. The variables evaluated were: dry weight of shoot, crude protein, accumulation and nitrogen concentration in the shoot and determining the number of nitrogen-fixing bacteria in the soil. The fertilized soil dry matter production increased over the cuts. Among the strains Y2 showed higher accumulation of nitrogen and largest population of bacteria in the middle of the LGI culture. The nutritional characteristics of Xaraes grass declined as the cuts were made.