Bruno de Oliveira Dias

Decomposição e liberação de N, P e K de esterco bovino e de cama de frango isolados ou misturados

The use of organic residues in the crop fertilizations demand information about the dynamics of decomposition and release of nutrients contained therein. This study aimed to evaluate the decomposition and release of N, P and K from organic residues cattle manure and poultry litter isolates or mixed, using the method of decomposition bags (litterbag) in Alfissol of Coast Tableland in Paraiba State. The experiment was conducted in randomized block with treatments arranged in a factorial 3 × 2 × 5 refers to three organic residues [(cattle manure (CM), poultry litter (PL) and the mixture of these residues in the ratio of 1: 1, called mixed manure (MM)], the incorporation of two layers (0-10 and 10-20 cm) and six evaluation periods (0, 30, 90, 150, 210 and 270 days after application) and three replications. From the results it was observed that the depth did not affect the decomposition of organic residues CM and MM and that it was more rapid in PL (0.0035 g day-1), more slow in CM (0.0010 g day-1 ) and occurred at a speed intermediate in MM (0.0020 g day-1). It was release more faster of N in MM (0.0011 g day-1), of P in CM (0.0040 g day-1) and K on PL (0.0025 g day-1), with an upward trend in the release of N in the PL and P in all residues with the incorporation at 10-20 cm. After 270 daa, it was estimated that the release of nutrients in the residues CM, PL and MM in relation to the initial content was 5.0, 15.0 and 28.0% for N; 80.0, 68.0 and 47.0% for P; and 20.0, 53.0 and 32.0% for K. In absolute terms, these percentages represented, respectively, 19.0, 103.0 and 149.5 kg ha-1 N, 28.0, 18.0 and 15.0 kg ha-1 P, and 75.0, 493.0 and 209.0 kg ha-1 K. The organic residues proved inadequate to meet the demand alone nutritional short cycle crops in these soils.

Soil use and management systems, time since adoption, and their impacts over aggregation

The Cerrado biome is of notable territorial relevance in the state of Piaui, Brazil. This region is an area of reference for food production. The aim of this work was to evaluate the stability of soil aggregates in water, in function of different soil use and management systems, as well as of the time since adopting these systems in Cerrado areas in the southwest region of Piaui. In this study, nine soil use and management systems were evaluated, arranged in the following manner: no-tillage system of three and six years of use, pasture of two and six years, eucalypt of six and twelve years, conventional tillage of two and eight years, and native Cerrado (Savana). The analyzed variables were: organic carbon, mean geometric diameter, mean weight diameter, aggregate stability index and aggregate diameter classes. Aggregation in Ferralsol is favored by clay and organic carbon contents. The longer adoption time in the no-till, pasture and eucalypt systems favored soil aggregation, while in conventional tillage there was a reduction of the aggregates.

Efeito de doses de boro no crescimento vegetativo de girassol em diferentes classes de solos

Effect of boron levels in vegetative growth of sunflower in different soil classes The low availability of boron (B) in the soil is one of the limiting factors for the production of sunflower , which is an oleaginous plant characterized by broad climatic adaptability . The objective of this study was to evaluate the influence of boron rates applied in different soil classes on the development of sunflower cultivar Helium 863. The samples were collected in the layer 0-20 cm of the soil classes Gray Argisol ‐ GL, Red Yellow Argisol - RYA, Litholic Neosol - LN, Eutrophic Red Argisol ‐ ERA, Fluvic Neosol - FN and Haplic Vertisol ‐ HV. The experiment was arranged in a randomized block 4 x 6 factorial (soils x doses) design, with four replications. The experimental unit was represented by one plant per pot. The soils showed significant effect (p <0.01) for all growth parameters studied. The sunflower plants grown in the soils FN, HV, GL and LN showed the highest leaf area, the lar gest inflorescence diameter, the highest levels of foliar boron, lar gest number of leaves and highest plant height, respectively . Fertilization with boron did not influence the production of dry matter of sunflower cv . Helium 863.