Adubação de sistemas: antecipação de adubação nitrogenada para a cultura do milho em integração lavoura-pecuária

Traditionally in no-tillage systems, fertilization is done to the catch crop. In general nutrient cycling in crop systems has not been treated as an important tool in the process of nutrient supplying for plants. The type and the condition in which vegetable residuesis decomposed can affect the efficiency of nutrient cycling.This study assessed the effect of anticipated nitrogen fertilization in crop-livestock systems on cultivated cornproduction, rate ofnutrient release from plant residue, and theN-minerallevels of soil. The study was carried out in the city Abelardo Luz (SC) in a Clayey Oxisol. The experimental design was a randomized block design with three replications. The treatments were arranged in a 2 x 2 factorial arrangement. The first factor was N Fertilization Time: in the N-Pasture level, nitrogen (200 kg ha-1 N) and N-Grains level, no nitrogen was applied. The second factor was the Grazing Height, characterized by two sward heights of oat at 15 cm (Low Height Pasture) and at 30 cm (High Height Pasture). Corn hybrid ‘Máximus’ was sowed in 10thOctober, 31 days after the removal of animals. In the twelve resulting plots from the combination of treatments on pasture phase (N Fertilization Time x Grazing Height) rates of N-fertilizer (0, 100, 200 e 300 Kg ha-1 of N) as urea were allocated in the split plot.We conclude that anticipated N fertilization of winter cover crop pasture to provide high-quality forage and carry-over N to the subsequent corn crop and may eventually replace side drees nitrogen fertilization on corn and can improve overall N fertilizer efficiency use in integrated crop-livestock systems.The rate of K release from plant residues is very fast, releasing large quantities in the first days after plant desiccation.Despite of considerably high nitrogen dose used in both the pasture and at the grain crop it was not observed nitrate leaching risks during the study period.

Efeito da adição de óleo essencial de Origanum vulgar e Ocimum gratissimum L. no perfil lipídico da gordura de palma usada em fritura de batata tipo chips

The objective of this study was to determine the antioxidant effect of essential oregano and alfavaca oil on the fatty acid profile of palm oil, used in industrial potato chips processing, aiming to reduce the oxidative state of palm oil. Essential oregano oil was obtained from industrial residues and commercial essential oregano oil was also acquired. The antioxidant activity of Oregano’s essential oil was taken by DPPH method. The DPPH analysis of the essential oil of oregano residue resulted in an IC50 of 797.04 mg.mL-1 and the essential oil of commercial oregano was 424.25 mg.mL-1. Regarding the content of total phenols, the essential oil of commercial oregano showed 0.167 ± 0.058 ug EAG.g-1. Based on these results, concentrations of 50, 100 e 150ug.g-1 of commercial oregano essential oil was added to palm oil and the fatty acid profile was determined by gas cromatography. Analysis were done with palm oil without being used in frying processes and without added essential oil, as well as with the different essential oil concentrations submitted at three frying processes at one single day. In the second part of the project, the effect of oreganos’s comercial essential oil compared to alfavacão essential oil, at the concentration of 100ug.g-1 in palm oil, and submitted to three frying processes during eleven cycles, was studied. The lipid profile was similar to that described in the literature, which an increase in the number of frying times caused a polyunsaturated fatty acids decrease and, therefore, a proportional increase in saturated fatty acids. It was noted an increase in the amounts of total saturated fatty acids from 43.36% (control) to 43.60% (palm oil with essential oil after 11 frying cycles at the concentration of 100ug.g-1). This fact proves that during the frying process, there is an increase in the rate of formation of saturated fatty acids. However, the addition of oregano essential oil did not provide significant change in the fatty acids of palm oil used in frying process of potato chips. The addition of oregano essential oil in a concentration of 100 ug./mL-1 until the third frying cycle showed a reduction effect of trans fatty acid formation. Although, during 11 frying cycles it was not noticed the essential oil effect under trans fatty acid formation. It can be suggested that this factor may be correlated to the frying time, which may not have been sufficient for significant formation of saturated and trans compounds.

Aplicação foliar de molibdênio em adubos verdes e o desempenho do feijoeiro em sucessão

The knowledge of molybdenum application in legumes on the availability of N, by BNF, increased enzymatic activity and the residual effect caused on crops growth and yield can contribute to the greater scientific understanding involved in green manure processes. The aim of this study was to evaluate the Mo application and the N from Crotalaria juncea and Canavalia ensiformis green manures on common bean performance. Were conducted field experiments for the crops succession system (green manures - common bean) and laboratory essays for the enzymatic activities. Green manure production was installed in a factorial arrangement 2 x 4, with two green manure legumes species, sunnhemp (Crotalaria juncea) and jack beans (Canavalia ensiformis), and four Mo doses (0, 40, 80, 120 g ha-1) in the form of sodium molybdate (Na2MoO4), foliar applied, in a randomized block design with four replicates. For succession crop (common bean) additional treatment was added, beans grown without any fertilization, following the same experimental design from the previous crop. The dry matter decomposition and the N mineralization of green manure were monitored through collection of residues over time, by using the litter bags method. In laboratory were carried out tests of nitrate reductase activity in green manures and common beans at 90 and 66 days after sowing, respectively. The sunnhemp responded linearly positively to the application of Mo as the dry matter and N accumulation. While the jack beans presented a negative quadratic response for dry matter and there was no adjustment of regression models to N. The jack beans showed a higher decomposition rate and N mineralization compared to sunnhemp. The half lives for decomposing 50% of dry matter on the soil was 123 and 104 days to sunnhemp and jack beans, respectively, and 50% of N present in the residues was mineralized at 93 and 85 days. In common bean, differed from the control for number of pods the dose of 40 g ha-1 of Mo in both species of green manures and the dose 80 g ha-1 of Mo in jack beans. For number of grains only in sunnhemp on the dose of 40 g ha-1 of Mo differ from the control. The nitrate reductase activity was influenced by developmental stage of green manure species. In common bean, the activity of nitrate reductase was up to three times higher than the dose 0 g ha-1 of Mo compared to treatment with application of Mo in both species. There was no effect of Mo doses or species of green manure on common bean yield.