RESUMO: O cultivo de milho RR® precedendo a soja, principalmente no sistema de semeadura direta, favorece a maior ocorrência de plantas voluntárias de milho RR®, interferindo em lavouras de soja. Plantas voluntárias de milho são originadas a partir de sementes perdidas na colheita ou não colhidas do campo, sendo estas, sementes individuais, que originam plantas individuais, ou várias sementes aderidas a segmentos da ráquis, que dão origem às touceiras. Milho voluntário na forma de touceiras predomina em lavouras de soja, porém poucas informações sobre seu efeito sobre a soja estão disponíveis na literatura. Durante dois anos foram realizados três experimentos em campo com o objetivo de avaliar o efeito das interferências de populações de milho voluntário RR® F2 oriundas de sementes individuais e de touceiras (sete plantas de milho emergidas no mesmo ponto) sobre os componentes do rendimento e o rendimento de grãos da soja. Os resultados demonstram que as perdas nos componentes do rendimento e no rendimento de grãos da soja são influenciadas pela população e origem do milho voluntário. Touceiras de milho causaram perdas superiores a 90% para populações acima de quatro touceiras m-2, enquanto a perda máxima média observada para plantas individuais foi de 83% nas maiores populações estudadas. O rendimento de grãos da soja reduziu de forma expressiva quando em competição com populações inferiores a uma planta ou touceira m-2, sendo de 16% e 46% na população de 0,5 planta individual e touceira m-2, respectivamente.

ABSTRACT: The cultivation of GR® maize prior to soybean, mainly in the no-tillage system favors the higher occurrence of GR® volunteer corn interfering in soybean crops. Volunteer corn originate from seeds that were lost during harvest or from non-harvested seeds from the field; these are individual seeds, originating individual plants, or several seeds adhered to segments of the rachis, which originate clumps. Volunteer corn in the form of clumps predominates in soybean crops, but little information about its effect on soybean is available in the literature. During two years, three experiments were carried out with the objective of evaluate the impact of the interference of GR® F2 generation volunteer corn populations coming from individual and clump seeds (seven corn plants emerged at the same point) over soybean yield components and grain yield. The results show that losses in soybean yield components and grain yield are influenced by the population and origin of volunteer corn. Clumps cause losses over 90% for populations above four clumps m-2, while the mean maximum loss observed for individual plants was 83% in the largest studied populations. Soybean yield decreased significantly when competing with populations below one plant or clump m-2, being 16% and 46% in the population of 0.5 individual plant and clump m-2, respectively.

The aim of this work was the study on the separation of soybean oil/n-butane mixtures using a commercial hollow fiber ultrafiltration membrane (50 kDa). Oil/n-butane mixtures with mass ratios of 1:1 and 1:3 (wt), with the feed pressures of 5, 7 and 10 bar and transmembrane pressure of 1 bar were studied. Rejections of oil between 21 to 97.2%, oil fluxes between 0.04 and 0.98 kg/m² h and n-butane fluxes between 4 and 46 kg/m² h were observed, strongly influenced by the feed concentration. The increase in oil/n-butane mass ratio caused an increase in oil rejection and a decrease in the permeate flux of oil for most assays. The increase in the operating pressure caused an increase in oil flux and a consequent decrease in oil rejection. No degradation was observed in the membrane module during the operation with this non-aqueous feed stream, as confirmed by integrity tests.

In this work, the separation of refined soybean oil/n-hexane mixtures was investigated using a commercial hollow fiber ultrafiltration membrane 50 kDa. Three alcohols with different chain lengths were tested for the conditioning of the membrane; n-propyl alcohol showed the highest n-hexane permeate flux after conditioning. There was a decrease in the rejection and an increase in permeate flux over time. This behavior may be related to swelling and membrane plasticization by the oil. Rejections from 10.0 to 28.7% and total permeate fluxes from 12.2 to 65.3 kg/m²h were observed. An increase in the oil/n-hexane mass ratio and the pressure caused an increase in the rejection and permeate total flux for most assays. No degradation was observed in the membrane module.