Navegando por Assunto "Cultura agrícola"

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Acesso aberto (Open Access)
Boas práticas agrícolas: análise de viabilidade financeira em propriedades sojicultoras e pecuaristas do Nordeste Mato-Grossense
(Universidade Federal do Pará, 2010-06-22) CHIACCHIO, Jayne Isabel da Cunha Guimarães; ALMEIDA, Oriana Trindade de; http://lattes.cnpq.br/0325909843645279
According to data from PRODES / INPE (2008), from 1988 to 2008, 369,154 km ² were deforested in the Amazon, an annual average of 17,578 km ². This process has been driven primarily by expansion of cattle ranching and agriculture. Several policies have been created to reduce deforestation. And these are targeted, usually by command and control instruments. A recent innovation, however, has been the search for improvements in environmental quality in medium and large farms through the introduction of Good Agricultural Practice (GAP). Based on this, this paper aims to examine whether the introduction of BPA in medium and large soy farms and ranches located northeast of Mato Grosso represents a financially viable alternative. The survey was conducted in five municipalities located northeast of Mato Grosso, in the Xingu watershed: Água Boa, Canarana, Querência, Bom Jesus do Araguaia and São Félix do Araguaia. First, we collected detailed data from activities in the region of study. For that, 40 farmers were interviewed (20 soy farmers and 20 ranchers). The second step raised the cost data of adoption of good practices on 14 soy farms and ranches found in the Registry of Social-Environmental Responsibility (RSR) of the Aliança da Terra (AT)/Instituto de Pesquisa Ambiental da Amazônia (IPAM). For the analysis of financial viability of Good Practice, we used three instruments: simple return, net present value (NPV) and internal rate of return. The results showed that BPA is capable of implementation, but there is a financial loss for the producer when he chooses to adopt BPA. However, opportunities for gains from adoption of BPA (such as the receipt by REDD, increased productivity, increased selling prices, among others) can reduce these "losses" and equalize the gains to production without BPA.
Acesso aberto (Open Access)
O plantio associado entre banana (Musa acuminata Cultivar Cavendish "Grande Naine") e feijão-de-porco (Canavalia ensiformis (L.) D. C.): uma avaliação agronômica dos efeitos da competição por água, nitrogênio e energia luminosa
(Universidade Federal do Pará, 2002-07-01) SILVA, Luis Mauro Santos; OZIER-LAFONTAINE, Harry
In tropical regions, intensive banana (Musa accuminata) monocropping has severe agronomic and environmental impacts, and the sustainability of this production is actually highly compromised. Yield reductions are principally due to the decrease of soil fertility and root systems damages by sod fungus and nematodes. Several alternatives actually aim to improve sustainable banana cropping systems. Among them, the cultivation of banana in cover-cropping systems with legumes is a promising one. The development of such systems, however, mainly depends on me knowledge and control of how the mixed component crop competes and affects the production of the principal banana crop. The goal of this study is to estimate the functioning of the banana canavalia ensiformis cover-crop system in field conditions Canavalia is an annual legume that is supposed to have nematode control properties. In this study, however, we focus only on the capacity of banana to perform in such cropping systems, under competition for environmental resources. It is a prerequisite to the development of further investigations uppon bio-control mechanisms that could be managed in integrated protection systems. An analysis of the elaboration of yield components during the vegetative phase of the growing cycle of the banana crop was performed: it is during that phase that the potential yield (number of fruits and fruit filling) is determined, and it is assumed that legume competition can affect yield elaboration. Three treatments were carried out: (i) BPO : banana pure crop, (ii) BA0 simultaneous mixed banana-canavalia, (iii) BA60: -mixed banana-canavalia with banana planted 2 months after canavalia. Growth and development parameter were registered weekly by non destructive methods (leaf area, leaf phenology, stipe height and diameter for banana, and canopy extension for canavalia). Destructive sampling were carried out twice a month to determine above ground dry matter (DM) and mineral composition of banana in the different treatments. In addition to this agronomical evaluation, we developed a banana-intercropped modal adapted from the STICS model for validation and scenario analysis. The analysis of the vegetative cycle of banana over 7 months shows that the plantation date is crucial for the success of the intercrop. There was no significant difference between BP0 and BA0 for DM before flowering (4,5 t MS ha-1 for BP0 against 4,2 t MS ha-1 for BA0). The number of weddings is also significantly reduced for 8 to 3 between BP0 and BA0, respectively. Bananas performances are, however, more affected in BP60. Here, banana DM is reduced lo 2,7 t ha-1, that can be explicated by a higher adverse effect by the canavalia that was dominant at the plantation of banana -- 74 cm height against 29 cm for banana. The performed yield analysis may be considered as an efficient approach for the evaluation of the vegetative phase of the banana, growing sole or intercropped. The analysis of the reproductive phase is actually carried out and should complete this first diagnosis. Model validation under simulated vs. observed data was satisfying. Scenario studies of pure crop situations predicted yield values of 28 ha -1 against 20 t ha -1 (1) in situation with 400 kg nitrogen ha -1 and 133 mm irrigation, (ii) in situations without fertilizers and irrigation, respectively. A simulated yield of 16 t ha-1 was obtained in the case of intercrop without inputs. Test of contrasting scenarios may be used as a decision tool for the definition of adapted intercropping patterns - optimization of plant density and synchronization of the plantation dates of the two species, for instance -, and new agronomical standards may be studied. These investigations, however, must be carried on with the purpose of mean and long term effects evaluation of these cover-cropping systems in relation with the evolution of soil bio-physic-chemical properties - organic matter status and evolution, soil fauna transformation, weeding -, and sustainability.
Acesso aberto (Open Access)
Produção de cana-de-açúcar nas condições climáticas Af
(Universidade Federal do Pará, 2014-03-28) MIRANDA, Augusto Sousa; DOMINGUES, Felipe Nogueira; http://lattes.cnpq.br/1461187309835749
The culture of cane sugar plays an important socioeconomic role in Brazil, with main products as sugar and alcohol, as well as being used as a source of roughage in food animal production systems. This study aimed to evaluate the behavior of the culture of cane of sugar grown in Af type weather, characterized by rainfall in all months of the year and no dry season weather conditions. IACSP93-6006, RB83-5486 and SP79-1011: The bromatological chemical composition, agronomic and technological characteristics of three cultivars of cane sugar were determined. Experiment was conducted in a randomized block design with three treatments and four replicates and the averages compared by Tukey test at 5% probability. There were differences (P˂0.05) for dry matter, ether extract, crude protein, acid detergent fiber, lignin, cellulose, neutral detergent fiber corrected for ash and protein, total carbohydrates, B2 fraction, fraction C and raw dry’s production. The components of the fibrous portion (NDF, LIG, fraction C) showed low values, resulting in higher value of non- fiber carbohydrates, which are interesting from the point of view of the cattle feeding, given that the components of the fibrous portion influence the intake and digestibility of the food. The cultivars showed higher dry matter production highlighting the IACSP93-6006 and SP79-1011 cultivars. For agronomic characteristics were no differences (P˂0.05) for the production of natural material, number of culms, culm length and culm diameter, highlighting the IACSP93-6006 and SP79-1011 cultivars, demonstrating adaptation to climatic conditions the region. There was no difference (P>0.05) for technological attributes, Pol, Brix, reducing sugars, purity, total reducing sugars, fiber and moisture, whose values were low due to rainfall in the region, because the cane sugar requires heat or water stress for maturation to occur. In weather conditions Af has no dry season being the least rainy month trial period had 106.6 mm and the average annual temperature was 26.8 ° C.
Acesso aberto (Open Access)
Simulation of soybean growth and yield under northeastern Amazon climatic conditions
(2011-06) SOUZA, Paulo Jorge de Oliveira Ponte de; FARIAS, José Renato Bouças; ABREU, José Paulo Mourão de Melo e; RIBEIRO, Aristides; ROCHA, Edson José Paulino da; BOTELHO, Marcel do Nascimento; SOUSA, Adriano Marlisom Leão de
The objective of this work was to parameterize, calibrate, and validate a new version of the soybean growth and yield model developed by Sinclair, under natural field conditions in northeastern Amazon. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, PA, Brazil, from 2006 to 2009. The climatic conditions during the experiment were very distinct, with a slight reduction in rainfall in 2007, due to the El Niño phenomenon. There was a reduction in the leaf area index (LAI) and in biomass production during this year, which was reproduced by the model. The simulation of the LAI had root mean square error (RMSE) of 0.55 to 0.82 m2 m-2, from 2006 to 2009. The simulation of soybean yield for independent data showed a RMSE of 198 kg ha‑1, i.e., an overestimation of 3%. The model was calibrated and validated for Amazonian climatic conditions, and can contribute positively to the improvement of the simulations of the impacts of land use change in the Amazon region. The modified version of the Sinclair model is able to adequately simulate leaf area formation, total biomass, and soybean yield, under northeastern Amazon climatic conditions.
Acesso aberto (Open Access)
Solar radiation use efficiency by soybean under field conditions in the Amazon region
(2009-10) SOUZA, Paulo Jorge de Oliveira Ponte de; RIBEIRO, Aristides; ROCHA, Edson José Paulino da; FARIAS, José Renato Bouças; LOUREIRO, Renata Silva de; BISPO, Carlos José Capela; SAMPAIO, Leila Sobral
The objective of this work was to evaluate the efficiency of soybean (Glycine max) in intercepting and using solar radiation under natural field conditions, in the Amazon region, Brazil. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, Pará state, during 2007 and 2008. The radiation use efficiency (RUE) was obtained from the ratio between the above-ground biomass production and the intercepted photosynthetically active radiation (PAR) accumulated to 99 and 95 days after sowing, in 2007 and 2008, respectively. Climatic conditions during the experiment were very distinct, with reduction in rainfall in 2007, which began during the soybean mid-cycle, due to the El Niño phenomenon. An important reduction in the leaf area index and biomass production was observed during 2007. Under natural field conditions in the Amazon region, the values of RUE were 1.46 and 1.99 g MJ-1 PAR in the 2007 and 2008 experiments, respectively. The probable reason for the differences found between these years might be associated to the water restriction in 2007 coupled with the higher air temperature and vapor pressure deficit, and also to the increase in the fraction of diffuse radiation that reached the land surface in 2008.