Effect of water and citrate solubility on agronomic effectiveness of acidulated phosphates in three consecutive corn crops

In the process of phosphate rock acidulation, several impure P compounds may be formed along with the desirable Ca and NH4 phosphates. Such compounds normally reduce the content of water-soluble P and thus the agronomic effectiveness of commercial fertilizers. In order to study this problem, a greenhouse experiment consisting of three consecutive corn crops was conducted in samples of a Red-Yellow Latosol (Typical Hapludox) in a completely randomized design (6 x 2 x 2), with four replicates. Six commercial fertilizers were added to 2 kg of soil at a rate of 70 mg kg-1 P, based on the content of soluble P in neutral ammonium citrate plus water (NAC + H2O) of the fertilizers. Fertilizer application occurred either in the original form or leached to remove the water-soluble fraction, either by mixing the fertilizer with the whole soil in the pots or with only 1 % of its volume. The corn plants were harvested 40 days after emergence to determine the shoot dry matter and accumulated P. For the first crop and localized application, the elimination of water-soluble P from the original fertilizers resulted in less bioavailable P for the plants. For the second and third crops, the effects of P source, leaching and application methods were not as evident as for the first, suggesting that the tested P sources may have similar efficiencies when considering successive cropping. The conclusion was drawn that the water-insoluble but NAC-soluble fractions of commercial P fertilizers are not necessarily inert because they can provide P in the long run.

Management of crotalaria and pigeon pea for control of yam nematode diseases

Management of plant-parasitic nematodes with the use of nematicides has not been recommended for small farmers that grow yam in the Northeastern region of Brazil, due to its high cost and residue toxicity. The use of plants with antagonistic effect to nematodes and green manure which improves soil chemical, physical and biological characteristics can be a viable and low cost alternative to control parasitic nematodes. This work aimed to evaluate the effect of crotalaria (Crotalaria juncea) and pigeon pea (Cajanus cajan) plants on the control of yam nematodes. Three experiments were carried out. The first was conducted under in vitro conditions to evaluate the nematostatic and nematicide effect of extracts from fresh and dry matter of the above ground parts of crotalaria, pigeon pea, and the combination of both. The second experiment was carried out under greenhouse conditions to evaluate the effect of soil amendment with crotalaria, pigeon pea, and the combination of both in the infectivity of Scutellonema bradys, using tomato plants as the host plant. The third experiment was conducted under field conditions to evaluate the effect of crotalaria, pigeon pea, and the combination of both, cultivated between yam planting rows and incorporated to soil surface, on yam nematodes. The aqueous extract obtained form fresh matter of crotalaria had a nematicide effect of 100% for S. bradys. Extracts from dry matter of both crotalaria and pigeon pea did not have any nematicide effect, but had a nematostatic effect. Incorporation of crotalaria to soil inhibited infectivity of S. bradys in tomato seedlings. These results showed that planting crotalaria alone or in combination with pigeon pea, between the yam planting rows, is an efficient method for controlling S. bradys and Rotylenchulus reniformis associated with yams. Crotalaria can be used for controlling these plant-parasitic nematodes in soil.

WHEAT HERBAGE AMENDMENTS ALTER EMERGENCE DYNAMICS, SEEDLING GROWTH OF LAMBSQUARTER AND SOIL PROPERTIES

ABSTRACT Crop allelopathy is a potential tool for weed management but allelopathic potential often varies among cultivars and developmental stages of crop. Bioassays were conducted to appraise the allelopathic potential of herbage (incorporated at 8 g kg-1 soil) of different hexaploid wheat (Triticum aestivum) cultivars (Millat-2011, AARI-2011, Lasani-2008 and Faisalabad-2008) collected at different crop growth stages [tillering (Z-30), anthesis (Z-60) and maturity (Z-90)] against lambsquarter (Chenopodium album). Mean emergence time taken by lambsquarter was prolonged over control by anthesis and maturity stage herbage of all wheat cultivars. Final emergence percentage was dropped by 3-17% in response to different growth stages of herbage collection. Maximum suppression in shoot (45 and 78%) and root (60 and 90%) length, and seedling dry biomass (65 and 96%) of lambsquarter over control was recorded under the amendment of anthesis and maturity stages herbage of wheat cultivars. Total chlorophyll contents declined in response to herbage collected at anthesis and maturity stage of all wheat cultivars over control. Phenolic contents on the other hand were increased. Activities of enzymatic antioxidants also varied among all wheat cultivars, and declined by the incorporation of tillering, anthesis and maturity stage herbage. Wheat herbage induced lipid peroxidation in lambsquarter seedling and higher malondialdehyde content (0.56 and 0.77 nmol g-1 FW) was observed by the incorporation of wheat cultivars herbage collected at anthesis and maturity stage, respectively. Anthesis and maturity stage herbage of wheat cultivars Millat-2011, AARI-2011 and Lasani-2008 was more phytotoxic than Faisalabad-2008. Moreover, tillering stage herbage of all wheat cultivars had less inhibitory potential against emergence, seedling growth and biochemical attributes of lambsquarter. Wheat herbage amendment increased the soil pH, phenolic, organic carbon and nitrogen contents as compared to control.

Tradução e adaptação cultural da Management of Aggression And Violence Attitude Scale – MAVAS – em enfermeiros brasileiros

Este estudo objetivou traduzir e adaptar culturalmente a Management of Aggression and Violence Attitude Scale – MAVAS – para uso no Brasil. As etapas metodológicas seguiram as diretrizes internacionais para adaptação cultural de escalas psicométricas: equivalência conceitual, equivalência semântica, equivalência de itens e equivalência operacional. A validade de conteúdo realizada por um grupo de juízes resultou numa escala composta por 23 itens divididos em quatro fatores com Coeficientes de Validade de Conteúdo (CVC) satisfatórios nos parâmetros avaliados: (0,88) para clareza de linguagem, 0,91 pertinência prática e 0,92 para relevância teórica. Os dados foram coletados no ano de 2011, em Londrina, PR, Brasil. Concluiu-se que a MAVAS-BR está traduzida e adaptada culturalmente para uso no Brasil e que o instrumento traduzido e adaptado apresenta validade de conteúdo satisfatória. Estudos futuros relacionados à MAVAS-BR são sugeridos, dentre eles a avaliação de suas qualidades psicométricas, como a validade de construto e a confiabilidade do instrumento.

MANAGEMENT OF IRRIGATION AND NITROGEN FERTILIZERS TO REDUCE AMMONIA VOLATILIZATION

ABSTRACT Nitrogen losses by ammonia (NH3) volatilization can be reduced by appropriate irrigation management or by alternative N sources, replacing urea. The objective of this study was to evaluate the efficiency of irrigation management and N source combinations in decreasing NH3 volatilization from an Argissolo Vermelho Distrófico típico cultivated for 28 years with black oat (Avena strigosa) and maize (Zea mays), under no-tillage in the region of Depressão Central, Rio Grande do Sul, Brazil. The experiment was arranged in a randomized block design with split plots with three replications, where the main plots consisted of irrigation systems: no irrigation; irrigation immediately before and irrigation immediately after fertilization. The subplots were treated with different N sources: urea, urea with urease inhibitor and slow-release fertilizer, at an N rate of 180 kg ha-1, broadcast over maize, plus a control treatment without N fertilization. Ammonia volatilization was assessed using semi-open static collectors for 1, 2, 4, 6, and 10 days after N fertilization. In general, more than 90 % of total NH3-N losses occurred until three days after N fertilization, with peaks up to 15.4 kg ha-1 d-1. The irrigation was efficient to reduce NH3 losses only when applied after N fertilization. However, reductions varied according to the N fertilizer, and were higher for urea (67 %) and slightly lower for urea with urease inhibitor (50 %) and slow-release fertilizer (40 %), compared with the mean of the treatments without irrigation and irrigation before fertilization. The use of urea with urease inhibitor instead of urea was only promising under volatilization-favorable conditions (no irrigation or irrigation before N fertilization). Compared to urea, slow-release fertilizer did not reduce ammonia volatilization in any of the rainfed or irrigated treatments.

Management of slips and its effect on growth and production of 'Pérola' pineapple plants

The lack of good quality planting material has limited the expansion and contributed to yield reduction of the Brazilian pineapple culture. Alternatives of 'Pérola' pineapple slips management were studied aiming at obtaining superior planting material within a shorter time period and making good use of healthy slips of low vigor, that are commonly discarded by growers. Two experiments were carried out at the Experimental Field of Embrapa Cassava & Fruits, Cruz das Almas, Bahia, Brazil, and another one in a commercial plantation in the region of Itaberaba, BA, using blocks or entirely randomized designs with at least four replications. In the first one, the development of slips of different initial sizes (6 to 20 cm long), when grown on mother plants after fruit harvest, was compared with that of slips grown in a nursery after their removal from the mother plants. It became clear that larger slips grow more vigorously and that the removal from the mother plant delays their growth. However, results from the second study showed that those slips grown in nursery had vegetative and agronomic performance similar to that of conventional slips and close to that of plantlets produced from plant stem sections. Independently from the type of planting material used, the larger ones presented a more vigorous growth and produced higher yields. In the third study, it was observed the influence of mineral fertilization, pest control and growth regulator application after fruit harvest on slip development. The treatments applied did not significantly accelerate slip growth. Slips reached 50 cm length and at least 300 g fresh weight within 90 days after fruit harvest, indicating that vigorous plants have enough nutritional storage material for slips development.

Simultaneous and accurate determination of water- and fat-soluble vitamins in multivitamin tablets by using an RP-HPLC method

In the present study, a reversed-phase high-performance liquid chromatographic (RP-HPLC) procedure was developed and validated for the simultaneous determination of seven water-soluble vitamins (thiamine, riboflavin, niacin, cyanocobalamin, ascorbic acid, folic acid, and p-aminobenzoic acid) and four fat-soluble vitamins (retinol acetate, cholecalciferol, α-tocopherol, and phytonadione) in multivitamin tablets. The linearity of the method was excellent (R² > 0.999) over the concentration range of 10 - 500 ng mL-1. The statistical evaluation of the method was carried out by performing the intra- and inter-day precision. The accuracy of the method was tested by measuring the average recovery; values ranged between 87.4% and 98.5% and were acceptable quantitative results that corresponded with the label claims.

Multifactorial control of water and saline intake: role of a2-adrenoceptors

Water and saline intake is controlled by several mechanisms activated during dehydration. Some mechanisms, such as the production of angiotensin II and unloading of cardiovascular receptors, activate both behaviors, while others, such as the increase in blood osmolality or sodium concentration, activate water, but inhibit saline intake. Aldosterone probably activates only saline intake. Clonidine, an a2-adrenergic agonist, inhibits water and saline intake induced by these mechanisms. One model to describe the interactions between these multiple mechanisms is a wire-block diagram, where the brain circuit that controls each intake is represented by a summing point of its respective inhibiting and activating factors. The a2-adrenoceptors constitute an inhibitory factor common to both summing points

The effects of water and sucrose contents on the physicochemical properties of non-directly expanded rice flour extrudates

Rice flour was processed by extrusion cooking in the presence of variable contents of water and sucrose. The process was carried out in a twin-screw extruder under the conditions given by a centre rotational experimental design of second order. The effects of the independent variables, water content (27.9 to 42.1%), and sucrose content (0.1 to 19.9%) on the physicochemical properties of the extrudates were investigated. The water absorption index (WAI), water solubility index (WSI), volumetric expansion index (VEI), and bulk density (BD) were determined as dependent variables. BD was determined for samples before and after frying. An increase in water contents resulted in higher WAI and VEI, and lower WSI and BD for extrudates before and after frying. Higher sucrose levels led to increased values of WAI and VEI and to reduced values of WSI and BD. Both independent variables had significant influence on the physicochemical properties of rice flour extrudates. However, the sucrose content was the most significant. The interaction between these two independent variables and their quadratic effect were also important for the responses studied.

Management zones definition using soil chemical and physical attributes in a soybean area

Several equipments and methodologies have been developed to make available precision agriculture, especially considering the high cost of its implantation and sampling. An interesting possibility is to define management zones aim at dividing producing areas in smaller management zones that could be treated differently, serving as a source of recommendation and analysis. Thus, this trial used physical and chemical properties of soil and yield aiming at the generation of management zones in order to identify whether they can be used as recommendation and analysis. Management zones were generated by the Fuzzy C-Means algorithm and their evaluation was performed by calculating the reduction of variance and performing means tests. The division of the area into two management zones was considered appropriate for the present distinct averages of most soil properties and yield. The used methodology allowed the generation of management zones that can serve as source of recommendation and soil analysis; despite the relative efficiency has shown a reduced variance for all attributes in divisions in the three sub-regions, the ANOVA did not show significative differences among the management zones.

Characterization of water availability in a hydrographic basin

The quantitative knowledge of hydrological parameters (rainfall and flow) and their spatial and temporal variability on the regions or basins should be understood as essential to the efficient planning and management of water resources. Because the Ivinhema Basin, located in the state of Mato Grosso do Sul, Brazil, represents an important inductor on the region agricultural development, characterized as a major producer of grains and meat, it was used to characterize the hydrological study. Knowing the rainfall, flow and drainage area of each of the studied affluent, it was calculated the proportion of contribution of the affluent. To that end, it was proposed the concepts of potential and real contributions, aiming to identify the proportion of contribution of each of the affluent to the formation of the flow in the Ivinhema Basin. The results revealed that: the highest rainfall in the Ivinhema Basin occurred in the headwater regions; the mean specific flow of long duration reduces from the headwater to the mouth of Ivinhema Basin; the Sub-basin of Dorado's River has the highest potential and real contribution for the formation of the Ivinhema Basin flow; and the drainage areas of the affluent Dourados and Vacaria contribute with 53% flow of the basin.

Impact of the substitution of reference annual streamflow by monthly streamflow on the potential use of water resources

The consideration of the streamflow seasonality has a high potential to improve the water use. In order to give subsidies to the optimization of water use, it was evaluated the impact of the change of reference annual streamflow by the monthly streamflows in the potential water use throughout the hydrography of Paracatu sub-Basin. It was evaluated the impact on Q7,10 (lowest average streamflow during a 7-day period with an average recurrence of 10 years) and on Q95 (permanent flow present 95% of the time). The use of monthly streamflow to substitute the annual streamflow had a high potential of improvement of water resources use in the sub-Basin studied. The use of monthly Q 7,10 in substitution of annual Q 7,10 increases the potential water use that vary from about 10% in the months of lower water availability to values exceeding 200% in the months with higher availability of surface water resources. The use of monthly Q95 in substitution of the annual Q95 implies in changes oscillating from reduction of 37% in months of higher water restriction to values exceeding 100% in the months of higher availability, so the use of monthly Q95 instead of the annual Q95 enables the more rational and safe use of water resources.

Oral administration of L-arginine decreases blood pressure and increases renal excretion of sodium and water in renovascular hypertensive rats

The two-kidney, one-clip renovascular (2K1C) hypertension model is characterized by a reduction in renal flow on the clipped artery that activates the renin-angiotensin system. Endothelium dysfunction, including diminished nitric oxide production, is also believed to play a role in the pathophysiology of this model. Some studies have shown an effect of L-arginine (L-Arg, a nitric oxide precursor) on hypertension. In the present study we determined the ability of L-Arg (7 days of treatment) to reduce blood pressure and alter renal excretions of water, Na+ and K+ in a model of 2K1C-induced hypertension. Under ether anesthesia, male Wistar rats (150-170 g) had a silver clip (0.20 mm) placed around the left renal artery to produce the 2K1C renovascular hypertension model. In the experimental group, the drinking water was replaced with an L-Arg solution (10 mg/ml; average intake of 300 mg/day) from the 7th to the 14th day after surgery. Sham-operated rats were used as controls. At the end of the treatment period, mean blood pressure was measured in conscious animals. The animals were then killed and the kidneys were removed and weighed. There was a significant reduction of mean blood pressure in the L-Arg-treated group when compared to control (129 ± 7 vs 168 ± 6 mmHg, N = 8-10 per group; P<0.05). Concomitantly, a significant enhancement of water and Na+ excretion was observed in the 2K1C L-Arg-treated group when compared to control (water: 13.0 ± 0.7 vs 9.2 ± 0.5 ml/day, P<0.01; Na+: 1.1 ± 0.05 vs 0.8 ± 0.05 mEq/day, respectively, P<0.01). These results show that orally administered L-Arg acts on the kidney, possibly inducing changes in renal hemodynamics or tubular transport due to an increase in nitric oxide formation.

Effect of sugar and water contents on non-expanded cassava flour extrudates

The effects of sucrose and water contents on cassava flour processed by extrusion at varied concentrations of sucrose (0-20% w/w) and water (28-42% w/w) were studied by applying response surface methodology. The extrusion of the mixtures was performed in a twin screw extruder fitted to a torque rheometer. The specific mechanical energy (SME) dissipated inside a conical twin-screw extruder was measured. Water absorption index (WAI), water solubility index (WSI) and paste viscosity readings (cold viscosity (CV), peak viscosity (PV), breakdown (BD) and set back (SB)) during a gelatinization-retrogradation cycle measured in a Rapid Visco Analyzer were determined on non-directly extruded products. The results indicated that SME and WSI decreased as a function of water and sucrose contents. WAI and pasting properties were influenced by water content. A non antiplasticizing effect of the sucrose content was observed on pasting properties, suggesting that sucrose did not reduce the availability of water available for gelatinizing cassava flour during the extrusion process. The nature of the optimum point was characterized as a saddle point for WAI, WSI, PV and BD, whereas SME showed a maximum and CV and SB a minimum. The results indicated to be valuable for the production of non-expanded cassava flour extrudates with desirable functional properties for specific end users.

Effects of water deprivation on renal hydroelectrolytic excretion in chronically Trypanosoma cruzi-infected rats

The effect of an 8 hour-period of water deprivation on fluid and electrolyte renal excretion was investigated in male Wistar rats infected with the strain São Felipe (12SF) of Trypanosoma cruzi, in comparison with age and sex matched non-infected controls. The median percent reductions in the urinary flow (-40% v -63%) and excretion ofsodium (-57% v-79%) were smaller in chagasic than in control rats, respectively. So, chagasic rats excreted more than controls. On the other hand, the median percent decrement in the clearance of creatinine was higher in chagasic (-51%) than in controls (-39%). Thus, chagasic rats showed some disturbed renal hydroelectrolytic responses to water deprivation, expressed by smaller conservation, or higher excretion of water and sodium in association with smaller glomerularfiltration rate. This fact denoted an elevation in the fractional excretion of sodium and water.