993 resultados para Tolerância à seca
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A greenhouse investigation was carried out to study the effects of liming on the dry matter (DM) production of the grasses Brachiaria brizantha (Hoscht.) Stapf. cv. Marandu, Andropogon gayanus Kunth cv. Planaltina and Panicum maximum Jacq cv. Aruana, cultivated on a Dark-Red Latosol, medium texture. The liming levels were obtained through the addition of carbonates in a Ca:Mg ratio of 4:1, necessary to increase the degree of base saturation (V%) to the following values; 4% (control), 20%, 36%, 52%, 68% and 84%. During the experimental period (180 days), four cuts were done to determine the DM production. The results indicated that the DM production was increased (P<0,05) with the liming-levels increased to the three grasses. Panicum maximum cv. Aruana yielded the lower DM quantity, but it presented a better response to liming. The inverse was observed in relation to A. gayanus. The data allowed to conclude that the DM production increased by liming and when the V% level was lower than 50%, it will be increased to 70% for establishment.
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This work aimed to evaluate the tolerance of sugarcane cultivars to sulfentrazone, imazapic, isoxaflutole, clomazone and ametryn + trifloxysulfuron-sodium. The experiment was arranged in a randomized block design in a split-plot scheme. The cultivars were allocated to the plots and the herbicides to the sub-plots (five 8.0 m long rows and 1.5 m spacing, with 4 repetitions. The herbicides sulfentrazone (0.8 kg ha(-1)), imazapic (0.147 kg ha(-1)), isoxaflutole (0.1125 kg ha(-1)), clomazone (1.1 kg ha(-1)), ametryn (1.463 kg ha(-1)) + trifloxysulfuron sodium (0.037 kg ha-1) and control were evaluated on 3-yr-old ratoons of the cultivars IACSP94-2094, IACSP94-2101, IACSP93-3046, IACSP94-4004, IAC86-2480 and RB72454 in post emergence. The traits evaluated were: plant toxicity symptoms in the plant leaves; total chlorophyll content and photochemical efficiency (Fv/Fm) at 15, 30 and 60 days after application (DAA); height (cm) at 30 and 270 DAA, and plant stand (stalk m(-1)) at 30 and 180 DAA. Diameter (cm), estimated productivity (t ha(-1)) and quality analysis were evaluated at 270 DAA. The sugarcane cultivars IACSP94-2094, IACSP93-3046, IACSP94-4004, IAC86-2480, RB72454, and IACSP94-2101 especially, were susceptible to clomazone up to 30 DAA, due to leaf chlorosis and lower chlorophyll content, but had no effect on quality characteristics and productivity. The cultivars were also tolerant to other herbicides.
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The objective of this study was to investigate the effect of the application of N fertilizer and the cutting age on the dry biomass production of elephant grass. The experiment was performed with the variety Paraiso and planted in a Ferralsol in 2008 in the district of Gurupi (State of Tocantins). Four different rates of urea application were tested (0, 50, 100 and 150 kg ha(-1)) and harvests were made at 120, 150 or 180 days after germination (DAG) of the setts. The dry matter and total N accumulation were evaluated. Dry matter production increased with dose of N, the greatest effect being observed at 180 DAG. There was a linear increase in dry matter (R-2 = 0.75**) and N accumulation (R-2 = 0.96**) permitting a productivity of 34 t ha(-1) of dry matter and an accumulation of 471 kg N ha(-1). The N utilization efficiency (biomass production per unit of applied N) increased with plant age. The higher efficiency of N use favored the quality of biomass production for energy production owing to the higher fibre content.
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Os caprinos têm um sistema de termorregulação que visa manter a temperatura corporal constante dentro de certos limites, independente da temperatura ambiente. Quando esses limites são estabelecidos, eles são usados em diversos mecanismos fisiológicos para manter a temperatura corporal (TC) dentro dos limites normais. Assim, a produção animal pode diminuir devido ao estresse térmico causado por temperaturas elevadas, especialmente em áreas semi-áridas como o Nordeste do Brasil. Este trabalho teve como objetivo avaliar o comportamento fisiológico de diferentes grupos genéticos de caprinos nativos de acordo com a resposta fisiológica das varáveis temperatura retal (TR), frequência respiratória (FR), batimentos cardíacos (BC) e movimentos ruminais (MR), e estabelecer os parâmetros fisiológicos para estas raças sob as condições do semiárido do Nordeste do Brasil. Foram selecionados aleatoriamente 30 animais, sendo cinco machos e dez fêmeas da raça Canindé e cinco machos e dez fêmeas da raça Moxotó, dos quais foram aferidos as variáveis BC, FR e TR nos meses de abril e setembro/2007 e 2008. Observou-se influência significativa (P<0,05) do período do ano no BC, na FR e na TR na raça Canindé, sendo observados valores mais elevados de BC e TR no período chuvoso. Na raça Moxotó observou-se uma diferença significativa (P<0,05) quanto ao BC e TR entre os períodos estudados, sendo observadas na estação seca maiores valores para estas variáveis. Também se observou nesta raça, uma correlação negativa (47%) entre a temperatura ambiente (TA) e TR no período seco, enquanto que no período chuvoso, essa correlação foi positiva (28%). A correlação entre TA e BC foi negativa (21%) no período chuvoso e, positiva (25%) no período seco. Na raça Canindé observou-se correlação negativa (39%) entre TA e movimento ruminal (MR) na época chuvosa, enquanto que no período seco, essa correlação foi positiva (33%). Os parâmetros clínicos avaliados neste estudo encontram-se dentro da normalidade para a espécie caprina no semi-árido nordestino e a raça Moxotó apresentou comportamento condizente com uma maior tolerância ao clima da região e um maior grau de adaptabilidade.
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The goal of this study was to evaluate the process of salting and dry salting of fillets in pacu (P. mesopotamicus), from cultivation in cages. Fillet with skin were salted at a rate of 40% of salt in relation of the initial weight, for a period of 10 days. After processing, were evaluated for microbiological and centesimal composition of fillets subjected to salting and determining the concentration of sodium chloride (NaCl) and calculation of income. The centesimal composition were evaluated the protein, ether extract, moisture and ash of the raw material fresh and processed products by salting. The microbiological analysis included the determination of coliforms at 45 degrees C, Salmonella and Staphylococcus coagulase positive. The pacus subjected to umided and dry salting were within quality control standards established by the legislation. The content of umided, protein, lipids and chlorides showed differences (p< 0.05) between the processes of salt. However both forms can be used for the development of technological processes of low investment by encouraging new options for fish consumption.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The nylon bag in situ degradation thecnique was employed to compare the data of the CNCPS to the ruminal degradability of the dry matter and crude protein in corn silage, soybean meal and sorghum grain, in four rumen fistulated Nellore steers, averaging 36 months of age and 520 kg of liveweight. A randomized complete block experimental design was used, where animals constituted the blocks. Two levels of concentrate, 18 and 39 %, were used in the diets. The forage used in the diets was corn silage and the concentrate ingredients were: soybean meal, cottonseed meal, corn grain and sorghum grain. There was a reduction in the potentially by degradable fraction (B) of the dry matter(DM) of the corn silage and sorghum grain with an increase in the concentrate level of the diet; however, the degradation rate(c) of the silage was similar for the two diets and the sorghum grain showed an increase of 28.4 %. The B fraction of the DM from the soybean meal was not affected by the diet, but its rate (c) was reduced by 18.1 %. The same effect was observed for the rate(c) of crude protein(CP) of the soybean meal, with a reduction of 38.1 %. The values for the effective degradability of the two fractions were not affected by the diet when the lag time was not considered. When lag time was considered, the degradability values of the studied feeds were superior in both fractions.
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The effect of Mg levels in nutrient solution upon root, stem, leaf, fruit and total dry matter production of common bean (Phaseolus vulgaris L. cv. Carioca) was studied. Bean plants were grown in Hoagland & Arnon n. 2 solution modified to obtain 2.4, 24.3, 48.6, 72.9 and 97.2 ppm of Mg. The experimental design was a split-plot factorial replicated three times with five Mg levels and five samplings which were done fortnightly. Results were compared with those observed in plants submitted to a nutrient solution with 48.6 ppm of Mg concentration, considered the ideal Mg content. Only a mild prejudicial effect was observed with Mg excessive levels. Stem, leaves and total dry matter were higher when 2.4 ppm were used, suggesting this level as the concentration chosen for the culture of common bean.
Matéria seca, concentração e acúmulo de nutrientes em mudas de Eucalyptus grandis em função da idade
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E grandis seedlings of Bofete progeny, cultivated in nurseries of Eucatex Florestal, were collected at ages of 55, 69, 83, and 97 days, separated into leaves, stem, and roots. The seedlings were then placed in identified paper bags, and oven-dried until weight became constant. They were then weighed and chemically analyzed for the determinate of dry matter production, concentrations and accumulation of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn in the several seedling ages. The distribution of total dry matter weight complied with the following descending order: leaf > stem > roots. Conversely to expectations, the highest concentrations of nutrients occurred in leaves for N and Mn only. Seedling hardened process resulted in N and S deficiency. The sequence of macronutrient concentration in seedlings at the time of shipment was the following: leaf > root > stem for N; root = stem > leaf for P; leaf = root = stem for K; stem > root > leaf for Ca; root > leaf > stem for Mg and S. All macronutrient concentrations in organs decreased with age, except for Ca. Concentrations of Cu, Fe, and Zn in all seedling specimens decreased with age. The sequence of micronutrient concentrations in seedling specimens at the time of shipment was the following: root >stem = leaf for B; root > stem > leaf for Cu and Fe; root > leaf > stem for Zn, and leaf > stem > root for Mn. At the time of shipment, at 97 days of age, K was the most extracted macronutrient of all, followed in a descending order by Ca, N, Mg, P, and e S. At the end of the seedling production rotation, Mn was the most extracted micronutrient, followed by Fe, Zn, Cu, and B.
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The geographic area of the present study corresponds to the basin of the Itiquira river high course (Figure 1), in the portion that extends from the tributaries of its source, in the east of the plateau Correntes/Itiquira, in the neighbourhoods the city of Alto Garç as, to the scarp of the São Jerônimo mountain range, toward the west of Itiquira, in the state of Mato Grosso, totalizing 5,361 km 2. The area is placed in the eastern part of the Alto Paraguai basin, in the western portion of the Paraná Sedimentary Basin plateau. Through GIS techniques, it was possible to asses total soil losses from the Itiquira river basin, considering the years of 1966, 1985 and 1996, being based on the Universal Soil Loss Equation. Thus, in 1966 the basin lost 201,546.94 ton of soil, with an average loss of 0.37 ton/ha/year. Considering that the total area of the Itiquira river basin is of 536,100 ha, while in 1985 the soil losses had passed to 1,760,833.40 ton, with an increase of approximately 8.5 times. The average of soil losses in 1985 was of 3.28 ton/ha/year. In 1996 the basin lost 1,662,043.24 ton, with a reduction of only 9.4% in relation to 1985 but, in relation the 1966, the increase continued in the order of 8 times. The average losses per hectare in this year was in the order of 3.10 ton/ha/year (Chart 1). The map of potential of the laminar erosion for 1966 (Figure 3), shows to the highest values in small areas, situated in the northeast of the area, in Alto Garças, with values between 10 the 20 ton/ha/year and some spots in sources of the Itiquira and Ariranha rivers, with values between 1 the 5 ton/ha/year. In a general way, however, the area presents low soil loss for laminar erosion in this year, with inferior values to 1 ton/ha/year. The higher class of erosion, over 10 ton/ha/year, occupied 2,947 ha in 1966. In the year of 1985 (Figure 4), the erosive process spread over the entire studied area, and the class of erosion over of 10 ton/ha/year, already started to occupy 78,437 ha, implying an increase of approximately 27 times in 19 years. A strong increment in the erosive process was noticed in the western part of the area, to along the BR-163 road, exactly where great areas of natural vegetation (open pasture) had been transformed in culture and pasture areas. In the north-eastern part of the area it was also noticed an increment in the erosive process in agreement with the increase of culture areas and reduction of the natural areas, but it was not of so intense form as in the western portion of the area. In the year of 1996 (Figure 5), the class of erosion over of 10 ton/ha/year had diminished for a total of 53.499 ha noticing a retraction of the erosive process in the western part of the area, alongside the BR-163 road. On the other hand, it occurred a strong increment in the northern part of the area, in the neighbourhoods of the city of Alto Garças, alongside the BR-364 road and part of the MT-040 road. In a general way, in the outskirts of the city of Itiquira, in the central part of the area, it was verified an increase of the amount of zones with erosion between 0-1 ton/ha/year, passing to the immediately superior class, of 1-3 ton/ha/year; scarce data of hydrosedimentology in the UHE Itiquira (1999), shows good agreement with the values gotten for the EUPS (Chart 2). Based on the hydric classification proposal for FAO (1967) (Chart 3), it is noticed that areas with high degree of erosion (> 50) in the analysed area are very restricted, occupying 493 ha in 1985 and 332 ha in 1996 (Chart 4). In 1996 appeared as isolated spots in the north of Itiquira and Alto Garças, however beyond limits of the Itiquira river basin. These areas require special cares in its use as agricultural areas. Aiming at identifying and indicating the areas of potential risk of erosion and that need implementation of conservation practices, it was elaborated the map of limit of tolerance to the soil losses. In 1966 (Figure 6), areas with soil losses over of the tolerable were restricted to small spots located in the eastern part of the area, occupying 0.43% of the total of the area; already in 1985 (Figure 7), this percentage passed to 5.86%, spreading for all the area; in 1996 (Figure 8) it is observed a fast reduction of the areas with soil losses over of the tolerance limit, passing 5.43% of the total of the area. All the areas with losses over of the tolerable value must be considered as risk areas and were done in these areas studies for implementation of conservation practices.
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The objective of this work was to evaluate the herbage availability, nutritive value, dry matter intake and grass and legume percentage in diet of crossbred Holstein-Zebu cows, in pasture with Brachiaria decumbens cv. Basilisk, Stylosanthes guianensis var. vulgaris cv. Mineirão and tree legumes. To estimate the fecal output, it was used 10 g cow -1 day -1 of chromium oxide during ten consecutive days. Extrusa samples were used to determine the chemical composition and in vitro dry matter digestibility. B. decumbens availability varied with climatic conditions, while S. guianensis availability decreased linearly along the experimental period. Dry matter intake was higher in May/2001 (1.9% body weight) and did not differ among other months (1.5% body weight). Low dry matter intake values were related to low in vitro dry matter digestibility coefficients (42.1 % to 48.0%) and high neutral detergent fiber content (70.2% to 79.4%). Dry matter intake was directly related to legume percentage in the pasture. This observation could indicate the potential of mixed pasture for improving nutritive value in dairy cattle diet.
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The balance of liming and fertilization practice with nitrogen and zinc could affect the production of the pasture. Thus, the present work has as objective to evaluate the residual effect of the application of calcareous rock, nitrogen, and zinc on the dry matter production of Brachiaria decumbens, during three cuts. For this, an experiment was installed in Selvíria, Brazil, on a distrofic red Latosol, from october 1997 to may 1998. The experimental design was randomized blocks, in a factorial project 3×3×2, with four repetitions. The treatments were three doses of nitrogen: 0, 50, and 100 kg/ha, three doses of lime: 0, 267, and 556 kg/ha, corresponding to 41, 50, and 60% of the levels of base saturation, respectively, and two doses of zinc 0 and 5 kg/ha, applied in the first year and reapplied in the second year, except for the limestone. Four cuts were done in the grass at 10 cm of height, with intervals of 49 days, to obtain the dry matter production. The limestone application in the first year did not provide to residual effect on the production of Brachiaria decumbens. However, the nitrogen fertilization increased the dry matter production of the grass. The application of zinc in the first year and the reapplication in the second year did not result in a productive response of B. decumbens. © 2009 Instituto Nacional de Investigaciones Agricolas INIA.
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The purpose of the work is to evaluate the stability by dry and humid of theaggregate in different systems or the use and management in Argissolos: agricultural, pasture and torest utilization. This work was realized in agricultural property, in Anhumas city, SR Several analyses including percentage of the aggregate (by way of dry and humid); the weighted mean diameter of the aggregate calculation and statistic analysis. Conclusion: the organic matter content of the A horizon of the soil under forest is 64 % more than the soil under pasture and 79 % more than the soil under annual crop; the WMDA of the aggregate obtained by dry and humid ways of the horizon A and its mean value for the soil decrease in the following sequence: PVAd - forest > PVe -pasture > PVd - annual culture, respectively, with the following values: 1.33560 and 1.445496 (D), 2.81114 and 2.351380 (H); 0.66748 and 1.011830 (D); 2.79642 and 1.624250 (H); 0.32468 and 0.993775 (S), 1.25808 and 0.983135 mm (H); the two methods are equally sensitive to reveal the effect of the soil use and management; the organic matter provides additional stability to the aggregates submitted to humid sieving and clay to the dry sieving: the WMDA obtained by dry and humid ways are statistically different for the soil profiles.
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This work was conducted throughout three phases of swine's growth (7 days from birth till the weaning age; from weaning until 7 days later and from 8 to 21 days after weaning); taking as objective the evaluation of the development of suckling and weaned piglets fed with a bran or extruded, dried and wet diet. We've used, for this paper, a total number of 31 pigs breeds, weaned and in average 21 day's lifetime and 3 different rations: dried bran; dried extruded bran and wet extruded bran (2 volumes of water to one volume of ration). During the 8th and 21st day after weaning all the animals received the same bran dried ration. Water and ration were supplied ad libitum. The experimental delimitation was totally random, with 3 treatments and eleven repetitions in the two first phases and five repetitions in the third phase, the multivariate variance analysis applied in the inferences about the results and from this we could conclude that the weight daily gain and the ration daily consumption were significantly not affected, i.e. by the processing, by the dry material ration content. However, we could observe a tendency to increase ration consumption and weight gaining when the animals were fed with bran extruded wet ration.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)