1000 resultados para espécie forrageira
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Inclui notas explicativas e bibliografia
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Mode of access: Internet.
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Among the species of freshwater shrimp being cultivated, Macrobrachium rosenbergii stands out. Knowledge about the behavior of this species and the influence of certain factors on its development can help optimize management practices and minimize the likely impacts shrimp farming has on the environment and the animals themselves. The objective of this study was to characterize the species' behavior during early stages of development under different stocking densities over a 24-hour cycle. Ten day old postlarvae were transferred from the Jundiaí School of Agriculture (EAJ - Escola Agrícola de Jundiaí) in Macaíba (RN), Brazil to the Shrimp Behavior Laboratory (LSPR - Laboratório de Estudos do Comportamento do Camarão) at the Federal University of Rio Grande do Norte (UFRN), where they were weighed and measured. Eight aquaria with constant temperature, aeration and filtration, and subjected to a12 h light/12 h dark cycle were used for each experiment. Each aquarium also contained two shelters made of bricks and the water quality was monitored weekly. Behavioral observations were made at two densities: 25 individuals/m-² and 40 individuals/m-². The methods for recording behaviors were: behavioral sampling – enter and leave the shelter, exploring on the substrate, exploring in the water column, move away, attack, pursuit and cannibalism; scan sampling - inactivity, feeding, exploration, digging, swimming, cleaning and staying in the shelter. Observations were made during a 15 minute period/per aquarium at a frequency of 4 times daily, for 4 days/week, and over 4 weeks. Food was provided 2 times/day for each aquarium population, immediately before the 1st and 3rd observation periods. Our results demonstrate that at high density, there is an increased frequency of agonistic behavior; during the light phase, there is a greater frequency of behaviors that result in less exposure (inactivity, cleaning and staying in the shelter); during the dark phase, there is an increased frequency of behaviors that result in greater exposure (feeding, exploration, swimming and digging); at times of feed offer, there is an increased frequency of leaving the shelter, moving away, pursuit, feeding, exploration and swimming. At low density, the animals showed a lower frequency of agonistic behaviors, greater weight gain and higher growth rates, which indicates that this is a more favorable growing environment for cultivation and when applied, can generate better living conditions, favor survival rates and increase management success
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The currently main development model on global society is driven by an economic rationality that endangers the environment and social justice. More and more, attention to this way of production and consumption is increasing, boosting research for sustainable development, with an environmental rationality that can harmonize nature preservation and welfare of all socioeconomic classes. One of the efforts on this sense is changing the sources supplying the energy demand, replacing fossil fuels for renewable and cleaner sources, such as biofuels. Carthamus tinctorius (safflower) is an oilseed crop with potential for biodiesel production, with good oil yield and chemical profile, allied to good adaptation to climates such like the northeastern semiarid lands of Brazil. With public policies fomentation, the use of this species may be an interesting alternative for family farming. In farming in general, the use of pesticides to prevent and combat diseases and plagues is common, which is not a sustainable practice. Thus, there are researched alternative, less dangerous substances. In this study, it was aimed to assess if neem (Azadirachta indica) leaf extract (20% m/v) and Bordeaux mixture (copper sulfate) have effects on safflower. It was also aimed to verify acceptance of farmers on safflower crop in Apodi, a municipality in Rio Grande do Norte state, Brazil, in view of it being localized in the aimed region for this crop cultivation. Besides that, understanding that the farmers’ knowledge and inclination to adopt the crop is fundamental for the introduction of this species and socioeconomic growth due to its exploration. In addition, a booklet with basic information on safflower was produced. In the field experiment, the fungicides were pulverized on plants cultivated in field experimental plots, with collection of leaf samples for analysis on anatomy, cuticle, and epicuticular wax morphology, the protective layer that interfaces with the surrounding ambient. In Apodi, forty-five farmers from Potiguar Cooperative of Apiculture and Sustainable Rural Development (COOPAPI) underwent semi-structured interviews, which also addressed their assessment on currently cultivated crops and perception of pesticide uses and sustainable alternatives. After comparing using analysis of variance, it was found that there was no difference between treatments in the experiment, as well as no anatomical or morphological modifications. Safflower acceptation among farmers was wide, with 84% of interviewees believing in a perspective of good incomes. The current scenario, comprised of low crop diversity, fragile in face of droughts and plagues, can partially explain this opinion. The booklet was effective in catching people attention for the species potential. There was wide acknowledgement on the importance of alternative pesticides, justified by health security. Based on the assessed parameter in the results of this research, the treatments here utilized may be recommended as fungicides for safflower. Given the crop susceptibility to fungi in heavy rainy period, it is advised that its potential introduction on the region shall be focused on semiarid areas.
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The cactus pear has become over the years an important forage alternative for brazilian semiarid region, especially during long periods of drought. Despite its importance for agriculture, its cultivation has dispensed basic crop practices and fundamentals technical-scientific basis about its climatic requirements. Thus, the main objective of this study was to elaborate the agroclimatic zoning of cactus pear (Opuntia sp.) for the state of Paraíba. The agroclimatic zoning of cactus pear was based on climatic indicators outlined in the literature and climatological data of precipitation and temperature (mean, maximum, and minimum) from 97 locations in the state of Paraíba. According to the results, the region of ‘Borborema’ is the most favorable for the cultivation of cactus pear. The regions of ‘Agreste’, ‘Sertão’, and coastal part of Litoral may be used but with restrictions. However, the cultivation of cactus pear is recommended throughout the state of Paraíba, except the coastal part of the Litoral and the region around Areia. In both cases, the inability is due to excessive precipitation.
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The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning