694 resultados para Função


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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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Pós-graduação em Matemática em Rede Nacional - IBILCE

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Pós-graduação em Agronomia (Ciência do Solo) - FCAV

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The sugarcane is a crop of annual cycle, where its large water demand is not always full, causing stand gaps in the sprouting of ratoons. Thus, this study aimed to assess the stand gaps in the first and second ratoon sugarcane under seven levels of water deficit. The experiment was conducted in the Center of Agricultural Sciences of the Federal University of Alagoas in the period of 22 February 2010 to 20 February 2012. The stand gaps depending on water depths ranged from 11.2 (25% ETo) to 16.8% (100% ETo) in the first ratoon and from 24.8 (0% ETo) to 32.8% (100% ETo) on second ratoon. The average size of stand gaps ranged from 0.60 to 0.68 m in the first ratoon and from 0.70 to 0.74 m on second ratoon. The average distance to find a stand gap ranged from 16.8 to 29.5 m in the first ratoon and from 6.5 to 10.9 m in the second ratoon. The percentage of gaps and the average size of the gaps in the sprouting of ratoon increase with the age of the sugarcane plantation and the average distance between gaps decreases. The use of irrigation in the culture of sugarcane increase the percentage of gaps, but because these spaces are filled with culms of other sugarcane clumps and were irrigated with larger water depths, the agricultural productivity of the culture increases. The depths of irrigation decreases the average distance between gaps with more intensity in the first than in the second ratoon.

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This research evaluated corn grains with flint and dent texture (ensiled high-moisture or dried), submitted to grinding degrees, using the in situ ruminal degradation technique. Three rumen canulated adult sheeps were used in a complete randomized design, using a factorial outline 2 x 2 x 3, with two corn hybrids (flint and dent texture), two conservation methods (ensiled high-moisture and dry) and three grinding degress (whole, coarsely and finely ground, corresponding to the sieve of 12; 10 and 8 mm). Starch soluble fraction (A) of the dent hybrid ensiled corn grains was greater comparing to the dry materials and in both conservation forms this fraction was reduced in the flint texture hybrid, while the insoluble fraction potentially degradable (B) the opposite occurred. The degradation potential was higher in grains ensiled in two textures. The ensiled allowed more starch effective degradation in relation to dry grain in two textures and the grains dent texture hybrid also increased such degradation in both conservation methods. The dent texture and the ensiled high-moisture grains proved the best option considering the starch degradability. Regardless of the conservation forms, the grains of corn hybrid flint texture should be finely ground, for providing higher ruminal degradation, while for the dent texture hybrid, the coarsely and whole grinding are the most suitable for ensiled and dry grain, respectively.

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To evaluate the effect of breed group, slaughter weight and sex on tissue proportion of the leg and muscle, bone and fat ratio in confined kids, seventy-four goats of both sex were used and divided among breed groups: Alpine (A), ½ Nubian + ½ Alpine (½ ANA), ½ Boer + ½ Alpine (½ BA), ¾ Boer + ¼ Alpine (¾ BA) and ½ Nubian + ¼ Alpine + ¼ Boer, (Three cross - TC), at three slaughter weights (25, 30 and 35 kg). Leg represented 31.01% of half carcass, where 62.29% was total muscle, 21.45% total bone and 8.35% total fat. Alpine animals had higher bone weight than other groups. Male kids had higher muscle and bone proportion, whereas females had higher subcutaneous and intramuscular fat in leg. The percentage of total weight of the muscle, five muscles, adductor muscle, quadriceps muscle and femur were higher in the slaughter weights of 25 and 30 kg.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The soil acidity in no tillage system could be resolved by lime superficial application, improvement to crop mineral nutrition and yield. The experiment carried out on a Rhodic Kandiudalf in Botucatu, São Paulo State, Brazil, in dry conditions, aiming to evaluate the agronomic development and leaf diagnosis of black oat plants, under superficial liming in no tillage system. A randomized complete block design was used, with four replications, the treatments were superficial application of different dolomítico lime rates (R0 = zero – without lime; R1 = 1,8 t ha-1 – lime to increase the base saturation at 50%; R2 = 3,6 t ha-1 – lime to increase the base saturation at 70% and R3 = 5,4 t ha-1 – lime to increase the base saturation at 90%), in October 2002. The black oat Common cultivar was seed in April 2004, in to second year, after the crop rotation of millet (spring) – common bean (summer) – black oat (autumn-winter). The results showed that: the black oat had yield increase by superficial liming, mainly to most dry matter and grain per panicule. Beyond, the superficial liming application did not prejudice leaf diagnosis of culture.

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Agricultural mechanization improved the efficiency of field operations by providing an increase in crop production. The intensified mechanization, however, has led to higher energy use mainly in the area of fuel consumption. The objective of this study was to compare the fuel consumption of tractors using two different tire pressures for two different types of soil during tillage with irrigated cotton in semi-arid regions. These tests were performed at the Maricopa Agricultural Center (MAC), an experimental farm belonging to The University of Arizona with a Case 4x2 TDA 88kW equipped with an autopilot system. The results showed lower fuel consumption using a tire pressure of 124 kPa on sandy clay loan soil.

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Currently, the efficiency in field operations and the increased productivity of crops is only possible with the use of agricultural machinery and equipment. This intensification of mechanized activities in agriculture, however, led to higher energy costs on farms mainly in the fuel consumption of agricultural tractors. The objective was to compare the fuel consumption of a tractor on tillage operations for irrigated cotton in semi-arid region varying two tire inflation pressures. The tests were conducted in Maricopa Agricultural Center (MAC), an experimental farm belonging to The University of Arizona using a 4x2 TDA Case tractor equipped with a 88kw autopilot system. The results showed lower values in the hourly fuel consumption by using the minimum tire inflation pressure of 124 kPa for all tillage equipment used.

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The current paper had as its objective to analyze the precision planter's operational performance according to five different displacement velocities and two types of jumpers for planting no-tillage corn. The utilized experimental delineation consisted of blocks at random with parcels subdivided in factorial scheme 2x5, two types of jumpers (4 and 5 staples) and five different displacement velocities (3.0; 4.5; 5.0; 7.0 e 9.0 km h-1) with four repetitions and by applying the average comparation test, as for the jumpers effects as for the displacement velocities effects, to the significance level of 5%. It was evaluated the data concerned to the longitudinal distribution of plants, average number of days for the emergence of seedlings, initial and final stand of plants, survival indices, mechanical harm on seeds, germination tests and grain production. It was also observed the planter displacement velocity effect of on variables as: longitudinal distribution of plants, average number of days for the emergence of seedlings, initial and final stand of plants, mechanical harm and yield. The survival indice of plants were high for all the studied velocities and jumpers. Among the studied velocities, the one of 5.0 km h-1 presented the highest yield to both types of jumpers.

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The objective of the study was to analyze the features of the relief through the variables: maximum altitude (HM); mean altitude (Hmd); minimum altitude (Hm); altitude range (H); average slope length (CVm); minimum length of run-off (Cd) and average steepness of circular samples (I) of the Capivara River Watershed – Botucatu (SP). A total of 4 circular samples were obtained per unit of soil (Quartzipsamment alfisol oxisol - RQ, Udox - LVA and Udorthent - RL). Multivariable analysis and aerial color photographs of 2000, Brazilian Chart and Soil Chart of Botucatu city-SP were used for data analyses. Soil differentiation was performed using the Student-t Test for analyzes of orthogonal contrasts among means of the three soils and analysis of groupings and major components. The grouping analysis of the variables of relief differentiated 75% of LVA and 100% of RL and RQ soil circular samples. The most efficient parameters of relief for differentiation of soils according to their order of importance were as follows: HM, Hm, Hmd and H.

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The inadequate soil use is an aggravating factor of the environmental degradation and ecological unbalance. The analysis of the use and covering of the soil, by information of Remote Sensing, constitutes a technique of great usefulness to the planning and administration of the ordered occupation and rational of the physical middle, besides making possible to evaluate and to monitor the preservation of areas of natural vegetation. This work sought to evaluate the conflicts of soil use in permanent preservation areas (PPA) in Stream Comur watershed - Botucatu (SP) through Geographical Information System and satellite image of 2009. The study area is located among the geographical coordinates 48o 23’ 04” to 48o 25’ 54” of longitude WGr. and 22o 44’ 42” to 22o 48” 12” of latitude S with an area of 1,719.6 ha. The results allowed to verify that the geoprocessing techniques were of fundamental importance in the identification of the areas of soil use, of APP and of conflicts among use and PPA where it leaves of the areas of APP is being used inadequately. In terms of environmental sustainability, it can be deduced that the watershed is very unfavorable, once it presents 70.67% of area used inadequately with sugarcane and pasture.

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The seedling transplanting ages is a factor of great importance because it can affect the quality and yield of plants if the volume of the cell is not compatible with the phenology of seedlings at time of transplantation. The experiment was conducted at São Manuel Experimental farm, Faculdade de Ciências Agronômicas da UNESP, from March to August, 2009. The objective of this study was to evaluate the effect of seedling age on cabbage production, hybrid Kenzan. The seedlings were grown in polystyrene trays containing 128 cells. Seedings were done every four days and contained the following treatments: 37, 41, 45, 49 and 53 days after sowing (DAS). The experimental design was randomized blocks, with five replications. On transplantation’s day (11/05/2009), the number of leaves, fresh and dry weight and height, were evaluated to the characterization of seedlings. It was observed that the seedling age had no influence on traits at harvest: number of leaves inside and outside of “head”, fresh weight of shoot and “head”, dry mass of shoot and “head” and length of “heart”.

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Water deficit is one of the factors which most limit agriculture yield and growth. Although sugar cane has moderate tolerance to drought, it presents high yield losses under the influence of this abiotic factor. Based on this fact, selection of genotypes tolerant to water stress may represent an alternative for decreasing the amount of water used for irrigation, while keeping or increasing yield. This study was performed in order to evaluate the performance of four sugarcane cultivars during initial development under water stress conditions, by means of morphological variables to select more tolerant genotypes to drought. The experiment was carried out in a greenhouse at the Department of Rural Engineering, College of Agricultural Sciences - UNESP/Botucatu – SP, from November 26th 2010 to April 5th 2011. A total of four sugar cane cultivars were evaluated (RB855453, RB92579, RB965902 and RB965917) under two treatments as follows: control (100% field capacity) and water stress (50% field capacity). Evaluations were performed at 0, 28 and 63 days after treatment application. The following morphological variables were analyzed: plant height, leaf area, leaf length, leaf width, number of green leaves, shoot and root dry matter. The RB855453 and RB92579 cultivars produced more shoot and root dry matter under water stress treatment, while the RB965902 and RB965917 cultivars had lower shoot and root dry matter production under the same conditions. Therefore, the RB855453 and RB 92579 cultivars can be considered tolerant while the RB965902 and RB965917 cultivars can be considered susceptible.