Volume 37, Number 3, 2013

The response of sugarcane to application of micronutrients is still not very well known. In view of the need for this information, the aim of this study was to evaluate the application of the micronutrients Zn, Cu, Mn, Fe, B, and Mo to plant cane in three soils, with and without application of filter cake. This study consisted of three experiments performed in the State of São Paulo, Brazil, (in Igaraçu do Tiete, on an Oxisol; in Santa Maria da […]

The interest in crambe (Crambe abyssinica ) cultivation in Brazil is on the rise, whereas information on the nutrient requirements for this crop is scarce. The objective of this work was to evaluate the effect of nitrogen-phosphorus-potassium (N-P2O5-K2O formula 8:28:16) fertilization (0, 150, and 300 kg ha-1) on crambe shoot biomass production, grain and oil yields, and nutrient extraction and exportation in the second growing season after soybean. The experiment with a Haplorthox (Dystroferric Red Latosol) was carried out for […]

Despite the large number of studies addressing the quantification of phosphorus (P) availability by different extraction methods, many questions remain unanswered. The aim of this paper was to compare the effectiveness of the extractors Mehlich-1, Anionic Resin (AR) and Mixed Resin (MR), to determine the availability of P under different experimental conditions. The laboratory study was arranged in randomized blocks in a [(3 x 3 x 2) + 3] x 4 factorial design, with four replications, testing the response of […]

Sulphur availability depends on the dynamics of its soil forms. An experiment was carried out to evaluate the effects of adding sulphur doses (0, 20, 50, 80, and 120 mg dm-3 of S), as calcium sulphate, and the incubation time (1, 8, 15, 30, 60, and 90 d) on the equilibrium between labile and non-labile sulphur reserves, in 10 soils. An anion exchange resin membrane was used to determine labile sulphur. A shaking period of 48 h (of water, soil […]

The efficiency of uptake of a nutrient by plants is a function of their physiological and morphological properties, which may vary between cultivars of the same species. A study was carried out to determine root morphology and kinetic parameters of potassium (K) uptake in rice genotypes. The experiment was conducted in a laboratory and the plants cultivated in pots under artificial light. Treatments were represented by 11 rice genotypes (Avaxi, BRS Atalanta, BRS Bojuru, BRS Fronteira, BRS Querência, CNA 10754, […]

Nickel is a micronutrient involved in nitrogen metabolism and a constituent of the urease molecule. Plant growth and urease activity were evaluated in lettuce (Lactuca sativa L.) grown in soil-filled pots in a 2 x 8 factorial design with two nitrogen (N) sources and eight Ni rates, with five replications. Nitrogen was applied at 200 mg dm-3 (half the dose incorporated into the soil at seedling transplanting and half top-dressed later) using the sources NH4NO3 (AN) and CO(NH2)2 (Ur). The […]

In Brazilian laboratories, the determination of micronutrient contents for soil fertility analyses is based on extraction with Mehlich-1 solution (M-1), at a 1:5 w/v soil:extractant ratio, with subsequent quantification by atomic absorption spectrometry (AAS). However, many laboratories also use a 1:10 w/v soil:extractant M-1 ratio for the determination of macronutrients, and/or quantification by optical emission spectrometry with inductively coupled plasma (ICP OES), instead of AAS. As comparative studies between the micronutrient concentrations obtained by these alternative methods are scarce, the […]

The N mineralization rate varies from one organic residue to another, and depends on the chemical composition of a residue and its interaction with the soil. This study assessed the dynamics of N mineralization of organic residues incubated in Oxisols. The experiment was carried out from July 2007 to April 2008. Samples of manures, sludges, composts, peat, and substrate were incubated in washed sand, in a Red Yellow Latosol (RYL), and in a Red Latosol (RL), with 240 and 670 […]

New technologies that enable a reduction in NH3-N volatilization losses should be developed to increase the N use efficiency of urea. The incorporation of boron and copper into urea can reduce these effects by inhibiting urease activity. The experiment was conducted in a greenhouse, testing the application of different N fertilizers (urea pellets with and without boron and copper, ammonium sulfate, urea with urease inhibitor NBPT, granulated urea and urea coated with boron and copper) to the surface of a […]

Coffee farmers from the physiographic region known as the Upper San Francisco River, MG, Brazil, have been adopting a new conservation management system with effects on the soil physical quality that require evaluation. The objective of this work was to study the physical quality of a Latosol and a Cambisol in contiguous areas under commercial coffee plantations. The soil of a transition area at the top of the landscape was classified as latossolic dystrophic Tb Haplic Cambisol (Inceptsol) and the […]