Soil Persistence of Chlorimuron-Ethyl and Metsulfuron-Methyl and Phytotoxicity to Corn Seeded as a Succeeding Crop

Two experiments were carried out to evaluate soil persistence of chlorimuron-ethyl and metsulfuron-methyl and phytotoxicity to corn seeded as a succeeding crop. One experiment was conducted with chlorimuron-ethyl applied at 20 g ha-1, and one with metsulfuron-methyl applied at 3.96 g ha-1. Treatments were arranged in a factorial design with two types of soil (sandy and clay), three irrigation regimes (daily, weekly and no irrigation) and four application timings (90, 60 and 30 days before corn seeding, as well as untreated plots). Soil persistence of the herbicides was influenced by water availability, molecule water solubility (leaching potential) and application timings prior to corn seeding. In sandy soil, with adequate water availability, leaching probably had the greatest influence, reducing the persistence of the products, and consequently allowing less time between product application and corn seeding. In clay soil, microbial degradation was probably more important, because it was assumed that the lesser time available for microorganism activity, the lesser the damage was observed for corn, as long as the crop had enough water availability. Metsulfuron-methyl was the least phytotoxic herbicide, possibly as a result of the properties of its molecule and its higher leaching potential.

EFFECTS OF PLANTING DATE AND SPATIAL ARRANGEMENT ON COMMON BEAN (Phaseolus vulgaris) YIELD UNDER WEED-FREE AND WEEDY CONDITIONS

ABSTRACTTo evaluate the effect of planting date and spatial pattern on common bean yield under weed-free and weed-infested conditions, an experiment was conducted in Kelachay, Northern Iran, in 2013. The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were planting date (10 August and 20 August), spatial pattern (square and rectangular planting pattern, with a planting distance of 30 x 30 cm and 45 x 20 cm, respectively), and weed management regime (weed-free and weedy conditions, weeded and not weeded throughout the growing season, respectively). Results showed that the main effect of planting date was significant only for pod number per plant and seed number per pod. At the same time, pod number per plant, seed number per pod, pod length, and grain yield were influenced significantly by spatial pattern. Results of ANOVA have also indicated that all traits, except pod length, were influenced significantly by weed-management regimes. Moreover, effect of planting date and spatial pattern were nonsignificant for weed dry weight. Mean comparison has expressed a significant increment in seed yield for square planting arrangement (1,055 kg ha-1) over rectangular (971 kg ha-1). Weeding has also presented an overall 12% and 8% improvement in grain and pod yield over control (weedy check), respectively. Based on the results of this study, weed control, as well as square planting pattern, are recommended for obtaining the highest seed yield in common bean.

EFFECT OF TRINEXAPAC-ETHYL ON GROWTH AND YIELD OF SUGARCANE

ABSTRACT Growth regulators can be used to further retard or inhibit vegetative growth. In this sense, the objective of this study was to determine the effects of age and number of trinexapac-ethyl applications on the growth and yield of sugarcane. The experiment was in a randomized complete block design with four replications. The treatments were in a 3 x 2 + 2 factorial arrangement, where factor A corresponded to the application times of the plant growth regulator (120, 200 and 240 days after bud burst (DAB) of sugarcane) and factor B to the number of applications (one or two applications). In addition, two controls (one with three applications and another application without the regulator) were added. The application of trinexapac-ethyl decreased the number and the distance between buds, height, root volume and sugarcane yield. The sequential application (2 or 3 times) induced an increase in stem diameter and three applications of the product increased the number of plant tillers. The use of growth regulators applied at 240 DAB has reduced plant height, however without changing the number of buds. It can be concluded that trinexapac-ethyl changes sugarcane growth and yield, regardless of season and number of applications.

WATER USE EFFICIENCY, GROWTH AND YIELD OF WHEAT CULTIVATED UNDER COMPETITION WITH Setaria

ABSTRACT Understanding the critical period of weed competition is indispensable in the development of an effective weed management program in field crops. Current experiment was planned to evaluate the critical growth period ofSetaria and level of yield losses associated with delay in weeding in rain-fed drip irrigated wheat production system of Saudi Arabia. Field experiment was conducted to evaluate the effect of weeding interval (07-21, 14-28, 21-35, 28-42 and 35-49 days after sowing) and drought stress (75% and 50% of field capacity) on Setaria growth, wheat yield and water use efficiency. Season long weedy check and wellwatered (100% FC) plots were also maintained for comparison. Weeding interval and drought stress significantly (p ≤ 0.05) affected the growth and yield of Setaria and wheat. Drought stress from 75% to 50% FC resulted in reductions of 29-40% in Setaria height, 14-27% in Setaria density and 11-26% in Setaria dry biomass. All weeding intervals except 35-49 DAS significantly suppressedSetaria growth as compared with control. Delay in weeding increased weed-crop competition interval and reduced wheat yield and yield contributors. Therefore, the lowest yield of 1836 kg ha-1 was attained for weeding interval of 35-49 DAS at 50% FC. Water use efficiency and harvest index increased with decreasing FC levels but reduced with delay in weeding. Correlation analysis predicted negative association ofSetariadensity with wheat yield and yield contributors and the highest negative association was for harvest index (-0.913) and water use efficiency (-0.614). Early management of Setaria is imperative for successful wheat production otherwise yield losses are beyond economical limits.

Wheat Yield Loss in a Two Species Competition with Emex australis and Emex spinosa

Emex australis and E. spinosa are significant weed species in wheat and other crops. Information on the extent of competition of the Emex species will be helpful to access yield losses in wheat. Field experiments were conducted to quantify the interference of tested weed densities each as single or mixture of both at 1:1 on their growth and yield, wheat yield components and wheat grain yield losses in two consecutive years. Dry weight of both weed species increased from 3-6 g m-2 with every additional plant of weed, whereas seed number and weight per plant decreased with increasing density of either weed. Both weed species caused considerable decrease in yield components like spike bearing tillers, number of grains per spike, 1000-grain weight of wheat with increasing density population of the weeds. Based on non-linear hyperbolic regression model equation, maximum yield loss at asymptotic weed density was estimated to be 44 and 62% with E. australis, 56 and 70% with E. spinosa and 63 and 72% with mixture of both species at 1:1 during both year of study, respectively. It was concluded that E. spinosa has more competition effects on wheat crop as compared to E. australis.

GROWTH AND YIELD RESPONSE OF MAIZE (Zea mays) TO INTER AND INTRA-ROW WEED COMPETITION UNDER DIFFERENT FERTILIZER APPLICATION METHODS

A field experiment was conducted for two consecutive years to study the effect of fertilizer application methods and inter and intra-row weed-crop competition durations on density and biomass of different weeds and growth, grain yield and yield components of maize. The experimental treatments comprised of two fertilizer application methods (side placement and below seed placement) and inter and intra-row weed-crop competition durations each for 15, 30, 45, and 60 days after emergence, as well as through the crop growing period. Fertilizer application method didn't affect weed density, biomass, and grain yield of maize. Below seed fertilizer placement generally resulted in less mean weed dry weight and more crop leaf area index, growth rate, grain weight per cob and 1000 grain weight. Minimum number of weeds and dry weight were recorded in inter-row or intra-row weed-crop competition for 15 DAE. Number of cobs per plant, grain weight per cob, 1000 grain weight and grain yield decreased with an increase in both inter-row and intra-row weed-crop competition durations. Maximum mean grain yield of 6.35 and 6.33 tha-1 were recorded in inter-row and intra-row weed competition for 15 DAE, respectively.

The Effect of Different Weed Management Strategies on the Growth and Yield of Direct-Seeded Dry Rice (Oryza sativa)

Weed management is a primary concern in direct seeded rice (DSR) cropping because weed growth becomes a major constraint on crop yield. A two year field study was set up to evaluate the effect of various weed control measures on crop growth, grain yield and grain quality of DSR. The experiment involved five different weed control measures: hand weeding, hoeing, inter-row tine cultivation, inter-row spike hoeing and herbicide treatment (Nominee 100 SC). The extent of weed control (compared to a non-weeded control) ranged from 50-95%. The highest crop yield was obtained using hand weeding. Hand weeding, tine cultivation and herbicide treatment raised the number of fertile rice tillers formed per unit area and the thousand grain weight. Tine cultivation provided an effective and economical level of weed control in the DSR crop.

Determining economical TBHQ doses for corn oil stability

Corn oil obtained from a Brazilian industry, free from antioxidants and citric acid, added of different tertiary butylhydroquinone (TBHQ) concentrations, was submitted to accelerated oxidation in the Schaal oven test at 63°C for 120 hours and for 168 hours in a photooxidation chamber. Peroxide and absorptivity values at 232nm and 270nm were determined for this oil. From the Schaal oven test results, the best and the economical TBHQ doses were determined to this oil. Afterwards, a shelf life experiment was conducted and confirmed 115mg.kg-1 TBHQ as the best and economical dose for that oil.

Evaluation of the in vitro glycemic index of a fiber-rich extruded breakfast cereal produced with organic passion fruit fiber and corn flour

The aim of this study was to determine the influence of process parameters and Passion Fruit Fiber (PFF) addition on the Glycemic Index (GI) of an extruded breakfast cereal. A 2³ Central Composite Rotational Design (CCRD) was used, with the following independent variables: raw material moisture content (18-28%), 2nd and 3rd barrel zone temperatures (120-160 ºC), and PFF (0-30%). Raw materials (organic corn flour and organic PFF) were characterized as to their proximate composition, particle size, and in vitro GI. The extrudates were characterized as to their in vitro GI. The Response Surface Methodology (RSM) and Principal Component Analysis (PCA) were used to analyze the results. Corn flour and PFF presented 8.55 and 7.63% protein, 2.61 and 0.60% fat, 0.52 and 6.17% ash, 78.77 and 78.86% carbohydrates (3 and 64% total dietary fiber), respectively. The corn flour particle size distribution was homogeneous, while PFF presented a heterogeneous particle size distribution. Corn flour and PFF presented values of GI of 48 and 45, respectively. When using RSM, no effect of the variables was observed in the GI of the extrudates (average value of 48.41), but PCA showed that the GI tended to be lower when processing at lower temperatures (<128 ºC) and at higher temperatures (>158 ºC). When compared to white bread, the extrudates showed a reduction of the GI of up to 50%, and could be considered an interesting alternative in weight and glycemia control diets.

Rheological behavior of corn and soy mix as feed ingredients

Foods behave as non-Newtonian fluids, but little is known about how corn and soybean mix behave under viscometric flow. In order to characterize the rheological behavior of animal feed under viscometric flow, a 70:30 (mass:mass) mixture of ground corn and soybean grains was submitted to a capillary rheometer at 3 different temperatures (80, 120, and 160 °C), different moisture levels (26.5 ± 0.08; 30.4 ± 0.31, and 33.4 ± 0.05%), and 4 shear rates (30.4; 72.9; 304.3, and 728.6/second). Different strain rates and die dimensions were used to obtain the target shear rates. The resulting data were fitted to Power Law, Casson, and Bingham models. Based on experimental data, water content, mass temperature, and the effects of shear rate on the apparent shear viscosity of corn-soy mix were fitted to a single expression (p < 0.001, R² = 0.93): η = 18,769.7 (y)-0.86 e (-9.34 U + 935 T), where y is shear rate, U is sample moisture, and T is sample temperature in Kelvin scale. As expected, such mixture presented a pseudoplastic (shear-thinning) behavior.

Production and partial characterization of alkaline polygalacturonase secreted by thermophilic Bacillus sp. SMIA-2 under submerged culture using pectin and corn steep liquor

Polygalacturonase production by the thermophilic Bacillus sp. SMIA-2 cultivated in liquid cultures containing 0.5% (w/v) apple pectin and supplemented with 0.3% (w/v) corn steep liquor, reached its maximum after 36 hours with levels of 39 U.mL-1. The increase in apple pectin and corn steep liquor concentrations in the medium from 0.5 and 0.3%, respectively, to 0.65%, markedly affected the production of polygalacturonase, whose activity increased four times, reaching a maximum of 150.3 U.mL-1. Studies on polygalacturonase characterization revealed that the optimum temperature of this enzyme was between 60-70 °C. Thermostability profile indicated that the enzyme retained about 82 and 63% of its activity at 60 and 70 °C, respectively, after 2 hours of incubation. The optimum pH of the enzyme was found to be 10.0. After incubation of crude enzyme solution at room temperature for 2 hours at pH 8.0, a decrease of about 29% on its original activity was observed. At pH 10.0, the decrease was 25%.

Corn germ with pericarp in relation to whole corn: nutrient contents, food and protein efficiency, and protein digestibility-corrected amino acid score

The germ fraction with pericarp (bran) is generated in the industrial processing of corn kernel, and it is used for oil extraction and animal feed. This study evaluated the nutritional and protein quality of this fraction in relation to whole corn. The proximate composition, mineral contents, and amino acid profile of the germ fraction with pericarp and of whole corn were determined. A 4-week experiment was conducted using 36 weanling male Wistar rats, and three 10%-protein diets (reference, germ with 15% lipids and casein with 15% lipids), two 6%-protein diets (whole corn and casein), and a protein-free diet were prepared. The germ showed higher contents of proteins, lipids, dietary fiber (27.8 g.100 g-1), ash, minerals (Fe and Zn- approximately 5 mg.100 g-1), and lysine (57.2 mg.g-1 protein) than those of corn. The germ presented good quality protein (Relative Protein Efficiency Ratio-RPER = 80%; Protein Digestibility-Corrected Amino Acid Score-PDCAAS = 86%), higher than that of corn (RPER = 49%; PDCAAS = 60%). The corn germ fraction with pericarp is rich in dietary fiber, and it is a source of good quality protein as well as of iron and zinc, and its use as nutritive raw material is indicated in food products for human consumption.

Color and chemical composition and of green corn produced under organic and conventional conditions

The present study aimed to evaluate the chemical properties of green corn, grown in both organic and conventional farming systems, using a completely randomized factorial design. Four corn varieties (AG 1051, BR 106, SWB 551 and VIVI) of green corn kernels were evaluated for color, proximate composition, total calories, carotenoids and bioactive amines. The farming system affected some chemical and physical characteristics of green corn, but this effect was dependent upon variety. In general, organic green corn kernels were reddish (a* color component) and had higher levels of β-carotene compared to the conventional ones, suggesting that these characteristics are related. Moreover, organic green corn had higher levels of total carbohydrates and total energy compared to conventional varieties. On the other hand, crude fiber levels were higher in conventional grains - an unexpected result that deserves further investigation. Finally, the levels of cadaverine and spermine bioactive amines were not affected either by the corn variety or by the farming system.

Simultaneous α-amylase and protease production by the soil bacterium Bacillus sp. SMIA-2 under submerged culture using whey protein concentrate and corn steep liquor: compatibility of enzymes with commercial detergents

Protease and α-amylase production by a thermophilic Bacillus sp. SMIA-2 cultivated in liquid cultures containing 0.25% (w/v) starch as a carbon source reached a maximum at 18 hours (47 U.mg-1 Protein) and 36 hours (325 U.mg-1 Protein), respectively. Culture medium supplementation with whey protein concentrate (0.1%, w/v) and corn steep liquor (0.3%, w/v) not only improved the production of both enzymes but also enabled them to be produced simultaneously. Under these conditions, α-amylase and protease production reached a maximum in 18 hours with levels of 401 U.mg-1 protein and 78 U.mg-1 protein, respectively. The compatibility of the enzymes produced with commercial laundry detergent was investigated. In the presence of Campeiro® detergent, α-amylase activity increased while protease activity decreased by about 27%. These enzymes improved the cleaning power of Campeiro® detergent since they were able to remove egg yolk and tomato sauce stains when used in this detergent.

Some functional characteristics of extruded blends of fiber from sugarcane bagasse, whey protein concentrate, and corn starch

Blends of fiber from sugar cane bagasse, corn starch, and whey protein concentrate were extruded. A single screw extruder, equipped with a screw at a constant compression ratio of 1:1 and a die diameter of 3 mm, was used. The best processing conditions were determined according to a central composite rotatable design (α = 1.41) with 5 central points, which gives a total of 13 tests. During the extrusion process the content of insoluble fiber decreased and that of soluble fiber increased. An increase in the contents of fiber and in the barrel temperature resulted in a decrease in the expansion index values and an increase in the water absorption index values; whereas in blends with intermediate fiber contents the effects in these parameters were found to be the opposite. High fiber contents increased penetration force but decreased luminosity, water solubility index values and the adhesive force in gels. The extrusion process improved the functional properties of sugarcane fiber bagasse enabling its addition to diverse alimentary systems.