141 resultados para doses and efficiency of nitrogen use
em Scielo Saúde Pública - SP
Resumo:
In order to identify alternatives for the use of saline water in agricultural production, the effects of the use of brackish water in the preparation of the nutrient solution for the cultivation of sunflower (cv. EMBRAPA 122-V2000) were studied in hydroponic system on consumption and efficiency of water use for the production of achenes and biomass. A completely randomized design was used, analyzed in a 5x2 factorial scheme with three replications. The factors studied were five levels of salinity of nutrient solution (1.7 - control; 4.3; 6.0; 9.0; and 11.5dS m-1) and two plant densities - one or two plants per vessel. It was concluded that the water consumption of sunflower is a variable sensitive to the salinity of the nutrient solution, especially after the fourth week of crop, and that the efficiency of water use in the production of achenes and biomass of sunflower is greater when the plant density increases from one to two plants per vessel, even under saline stress.
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Nitrogen supply and plant population are basic parameters for cereal-legume intercropping. In order to study plant population and nitrogen fertilizer effects on yield and yield efficiency of maize-bean intercropping, a field experiment was established. Three bean plant populations and three nitrogen levels were used. Maize dry matter accumulation decreased with increases in bean plant population. Competitive effect of intercrop beans on maize yields was high at higher plant populations, being decreased by nitrogen fertilizer; application of 50 kg ha-1 N was very efficient in increasing maize cob yield. Intercropping significantly decreased harvest index of beans in all plant population and nitrogen fertilizer situations. The efficiency of intercropping, compared to sole cropping, was evidenced by the values obtained for Land Equivalent Ratio (LER) for biomass, cob and pod yields that increased with increases in bean plant populations and nitrogen fertilizer levels.
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NBPT (N-(n-butyl) thiophosphoric triamide), a urease inhibitor, has been reported as one of the most promising compounds to maximize urea nitrogen use in agricultural systems. The objective of this study was to evaluate the performance of irrigated wheat fertilized with urea or urea + NBPT as single or split application. The experiment was conducted from June to October 2006 in Viçosa, MG, Brazil. The experimental design followed a 2×2 factorial scheme, in which urea or urea + NBPT were combined with two modes of application: full dose at sowing (60kg ha-1) or split (20kg ha-1 at sowing + 40kg ha-1 as topdressing at tillering), in randomized blocks with ten replications. The split application of nitrogen fertilization does not improve the yield wheat under used conditions. The use of urease inhibitor improves the grain yield of wheat crop when urea is applied in topdressing at tillering, but its use does not promote difference when urea is applied in the furrow at planting.
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In order to select soil management practices that increase the nitrogen-use efficiency (NUE) in agro-ecosystems, the different indices of agronomic fertilizer efficiency must be evaluated under varied weather conditions. This study assessed the NUE indices in no-till corn in southern Paraguay. Nitrogen fertilizer rates from 0 to 180 kg ha-1 were applied in a single application at corn sowing and the crop response investigated in two growing seasons (2010 and 2011). The experimental design was a randomized block with three replications. Based on the data of grain yield, dry matter, and N uptake, the following fertilizer indices were assessed: agronomic N-use efficiency (ANE), apparent N recovery efficiency (NRE), N physiological efficiency (NPE), partial factor productivity (PFP), and partial nutrient balance (PNB). The weather conditions varied largely during the experimental period; the rainfall distribution was favorable for crop growth in the first season and unfavorable in the second. The PFP and ANE indices, as expected, decreased with increasing N fertilizer rates. A general analysis of the N fertilizer indices in the first season showed that the maximum rate (180 kg ha-1) obtained the highest corn yield and also optimized the efficiency of NPE, NRE and ANE. In the second season, under water stress, the most efficient N fertilizer rate (60 kg ha-1) was three times lower than in the first season, indicating a strong influence of weather conditions on NUE. Considering that weather instability is typical for southern Paraguay, anticipated full N fertilization at corn sowing is not recommended due the temporal variability of the optimum N fertilizer rate needed to achieve high ANE.
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The aim of this study was to evaluate of Pleurotus sajor-caju production in peach palm leaves and the addition of different fractions of mushroom powder to wheat flour to increase its nutritional value without changing its characteristics. The best yield (48.4%), biologic efficiency (4.5%), and Pr (0.36 g/day) values were obtained using 20% inoculum fraction and 10% rice bran fraction. The Pleurotus sajor-caju fruiting body cultivated under these conditions had the following composition in 100 g: 29.91 g (carbohydrates), 42.92 g (proteins), 1.24 g (lipids), 15.93 g (fibers), 7.42 g (ashes), 1.6 g (phosphorus), 2.7 g (potassium), 8.73 mg (iron), 23.75 mg (sodium), 0.34 mg (thiamine), and 0.57 mg (riboflavin). The wheat flour with mushroom powder had reduced sugar content, but it did not have increased fat content. The fiber, protein, phosphorus, potassium, iron, and riboflavin contents were increased mainly when 10% mushroom powder was added to the wheat flour. Furthermore, this flour does not undergo drastic alterations in its physicochemical characteristics such as in moisture, wet gluten, color, and falling number.
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Leishmania braziliensis is a causative agent of American Cutaneous Leishmaniasis (ACL). The 034-JCG strain, isolated from a patient from the northern region of Paraná State, Brazil, was cultivated in Blood Agar Base medium, lyophilized and submitted to phenol-water extraction. The extract was treated with RNase I. The carbohydrate containing-antigen (Ag-CHO) was immunogenic to rabbits and showed at least a fraction with some negative charge at pH 8.2. This antigen showed cross-reactivity with the phenol-water extract of the growth medium used for the culture of promastigotes and with the surface antigens of promastigotes. Its composition is: 24.3% of total sugars, from which 11.2% of galactose, 7.5% of mannose and 5.6% of ribose. Protein content was 5.4% and phosphate 18.5%. The antigenic activity was maintained after: repeated freezing-thawing; lyophilization; heating at 100ºC for 30 minutes; treatment with RNase, trichloroacetic acid and sodium metaperiodate. The precipitin line obtained is Periodic Acid Schiff positive. The application of the Ag-CHO in counterimmunoelectrophoresis reaction for the immunodiagnosis of ACL showed 60% sensitivity, and no cross-reaction with the five sera of Chagas' disease patients tested. The use of this antigen in a more sensitive technique, with more samples of sera, may improve these results.
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Introduction Methicillin-resistant Staphylococcus aureus (MRSA) is among the most important pathogens of nosocomial infections, mainly in intensive care units (ICUs), and accounts for 40-60% of all healthcare-associated S. aureus infections. We evaluated the incidence of nosocomial infection by S. aureus, identified the risk factors for MRSA infection, and evaluated the effect of resistance to methicillin on mortality in patients. Methods We conducted MRSA surveillance at a university hospital in Brazil from January 1, 2010, to December 31, 2010, and performed a retrospective case-control matched study to evaluate the frequency of subsequent MRSA bacteremia and death among patients. We evaluated and compared the risk factors between patients with MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) infection. Results Sepsis was the most common cause of infection (17.7/1,000 patient-days), followed by surgical site (11.4/1,000 patient-days), pneumonia (4.1/1,000 patient-days), and urinary tract infection (2.4/1,000 patient-days). The significant risk factors were time of hospitalization, use of central vascular catheter (CVC), urinary catheter, nasogastric tube, parenteral nutrition, tracheostomy, mechanical ventilation, and previous antibiotic administration, the latter of which was the only independent risk factor for MRSA infection. Mortality was significantly higher in patients with MRSA. The number of antibiotics tested was not related to increases in the frequency of MRSA/1,000 patient-days. The incidence of mortality attributable to MRSA (bloodstream infection) BSI was 50%. Conclusions Surveillance results showed that the use of high levels of antibiotics was directly related to the development of MRSA infection, and the mortality attributable to MRSA in patients with bacteremia was significant.
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The present work deal t wi th an experiment under field conditions and a laboratory test of soil incubation the objectives were as follows: a. to study effects on soybean grain product ion and leaf composition of increasing doses of potassium chloride applied into the soil through two methods of distribution; b. to observe chemical modifications in the soils incubated with increasing doses of potassium chloride; and, c. to correlate field effects with chemical alterations observed in the incubation test, The field experiment was carried out in a Red Latosol (Haplustox) with soybean cultivar UFV - 1. Potassium chloride was distributed through two methods: banded (5 cm below and 5 cm aside of the seed line) and broadcasted and plowed-down. Doses used were: 0; 50; 100 and 200 kg/ha of K2O. Foliar samples were taken at flowering stage. Incubation test were made in plastic bags with 2 kg of air dried fine soil, taken from the arable layer of the field experiment, with the following doses of KC1 p,a. : 0; 50; 100; 200; 400; 800; 1,600; 3.200; 6,400 and 12,800 kg/ha of K(2)0. In the conditions observed during the present work, results allowed the following conclusions: A response by soybean grain production for doses of potassium chloride, applied in both ways, banded or broadcasted, was not observed. Leaf analysis did not show treatment influence over the leaf contents for N, P, K, Ca, Mg, and CI, Potassium chloride salinity effects in both methods of distribution for all the tested closes were not observed.
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OBJECTIVE Assessing the adequacy of knowledge, attitude and practice of women regarding male and female condoms as STI/HIV preventive measures. METHOD An evaluative Knowledge, Attitude and Practice (KAP) household survey with a quantitative approach, involving 300 women. Data collection took place between June and August 2013, in an informal urban settlement within the municipality of João Pessoa, Paraiba, Northeast Brazil. RESULTS Regarding the male condom, most women showed inadequate knowledge and practice, and an adequate attitude. Regarding the female condom, knowledge, attitude and practice variables were unsatisfactory. Significant associations between knowledge/religious orientation and attitude/education regarding the male condom were observed. CONCLUSION A multidisciplinary team should be committed to the development of educational practices as care promotion tools in order to improve adherence of condom use.
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The genetic diversity of ten Bradyrhizobium strains was evaluated for tolerance to high temperatures, to different salinity levels and for the efficiency of symbiosis with cowpea plants (Vigna unguiculata (L.) Walp.). Eight of these strains were isolated from nodules that appeared on cowpea after inoculation with suspensions of soil sampled from around the root system of Sesbania virgata (wand riverhemp) in ecosystems of South Minas Gerais. The other two strains used in our analyses as references, were from the Amazon and are currently recommended as cowpea inoculants. Genetic diversity was analyzed by amplifying repetitive DNA elements with the BOX primer, revealing high genetic diversity with each strain presenting a unique band profile. Leonard jar assays showed that the strains UFLA 03-30 and UFLA 03-38 had the highest N2-fixing potentials in symbiosis with cowpea. These strains had more shoot and nodule dry matter, more shoot N accumulation, and a higher relative efficiency than the strains recommended as inoculants. All strains grew in media of pH levels ranging from 4.0 to 9.0. The strains with the highest N2-fixing efficiencies in symbiosis with cowpea were also tolerant to the greatest number of antibiotics. However, these strains also had the lowest tolerance to high salt concentrations. All strains, with the exceptions of UFLA 03-84 and UFLA 03-37, tolerated temperatures of up to 40 ºC. The genetic and phenotypic characteristics of the eight strains isolated from soils of the same region were highly variable, as well as their symbiotic efficiencies, despite their common origin. This variability highlights the importance of including these tests in the selection of cowpea inoculant strains.
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Nitrogen is the most important nutrient for rice (Oryza sativa L) yields. This study aimed to evaluate the response of upland rice cultivars to N rate and application times in a randomized block design, in subdivided plots with four replications. The studied factors were five rice cultivars (BRS MG Curinga, BRS Monarca, BRS Pepita, BRS Primavera, and BRS Sertaneja), three application times (100 % at planting, 50 % at planting - 50 % at tillering and 100 % at tillering) and four N rates (0, 50, 100, and 150 kg ha-1). All cultivars responded to increased rates and different times of N application, especially BRS Primavera and BRS Sertaneja, which were the most productive when 50 % N rates were applied at sowing and 50 % at tillering. The response of cultivar BRS Monarca to N fertilization was best when 100 % of the fertilizer was applied at tillering.
Resumo:
The objective of this study was to evaluate the effects of foundation and leaf fertilization with micronutrients on fruit size and quality of pineapple cv. Vitória under the environmental conditions of the Baixo Acaraú irrigated perimeter in Northern Ceará State, Brazil, under two covers (bagana and black plastic) of the sandy soil of low fertility. The experimental design was a randomized split blocks one with four levels of soil dressing and four levels of foliar fertilization, with five replications. Micronutrient soil dressing was studied as FTE-12 at doses of 0, 60, 120 and 180 kg ha-1. The four levels of foliar fertilization were: LF0 (without fertilizer), LF 1 (15 leaf fertilization, using the amount of 1158.75 g Fe ha-1, 844.65 g Mn ha-1, 391.5 g ha-1 Zn, 322.65 g ha-1 Cu and 216 g ha-1 B), LF2 (15 leaf fertilization, using twice the quantities of level LF1) and LF3 (15 leaf fertilization, using three times the amount of level LF1). At 13 months after planting the micropropagated plantlets was carried out the floral induction treatment and five months later the fruit harvest determining the following variables: fruit weight and median diameter, soluble solids content (SS) and titratable acidity (TA). Both fruit weight and diameter increased with increasing doses of micronutrients applied to the soil and to the leaves, of plants grown both on bagana soil cover and plastic mulch. On the other hand fruit pulp quality was little affected by the treatments studied. There were a small increase of SS contents for plants grown on bagana soil cover and a small decrease of titratable acidity for those grown on plastic mulch, in both cases just in response to micronutrient foliar application.
Resumo:
Two soybean (Glycine max) cultivars were used in this study, Ocepar 4, rated as moderately resistant to Meloidogyne incognita race 3 but susceptible to M. javanica, and 'BR 16', susceptible to both nematodes. The effect of nematodes infection on the uptake and transport of N, P and Ca to the shoot was studied in plants growing in a split root system. The upper half was inoculated with 0, 3,000, 9,000 or 27,000 eggs/plant while the lower half received 15N, 32P or 45Ca. Infected plants showed an increase of root but a decrease of shoot mass with increasing inoculum levels. In general, total endogenous nutrients increased in the roots and tended to decrease in the shoots with increasing inoculum levels. When concentrations were calculated, there was an increase in the three nutrients in the roots, and an increase of Ca but no significant variation of N and P was observed in the shoots. The total amount of 15N in the roots increased at the highest inoculum levels but 32P and 45Ca decreased. In the shoots there was a reduction of 32P and 45Ca. The specific concentrations of the labelled nutrients (abundance or radioactivity/tissue mass) also showed a decrease of 32P and 45Ca in the shoots and roots of infected plants and an increase of 15N in the shoots. Considering that overall nutrient concentrations reflect cumulative nutrient uptake and the data from labelled elements gave information at a specific moment of the infection, thus nematodes do interfere with nutrient uptake and translocation.