Navegando por Assunto "Monocultura"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Agroestratégias e monocultivos de dendê: a transferência silenciosa das terras da reforma agrária para o grande capital na Amazônia paraense
(Universidade Federal do Pará, 2015-10-27) SILVA, Elielson Pereira da; FARIAS, André Luís Assunção de; http://lattes.cnpq.br/5310171409459863; SANTOS, Sônia Maria Simões Barbosa Magalhães; http://lattes.cnpq.br/2136454393021407
Acesso aberto (Open Access)
Agronegócio do dendê: evolução no Estado do Pará, no Brasil e no Peru
(Universidade Federal do Pará, 2015-12-03) VÁSQUEZ, Jorge Arturo Mori; ALMEIDA, Oriana Trindade de; http://lattes.cnpq.br/0325909843645279
Oil palm monoculture is increasing in the world and in the entire Amazonian watershed. It is therefore necessary to have a scientific insight on the applied public policies of this sector, it is also important to assess the influence of technological changes in order to enhance positive impacts and to neutralize or mitigate negative impacts. It was used an evolutionary approach to determine the influence of; public policy of tax exemptions and credits (which allowed a strong initial capitalization of companies in the sector), the creation or adaptation of state organizations (to promote the development of plantations), as well as the technological development of breeding, pest management (to increase the production), harvest of fresh fruit branches (to reduce cost and increase production) and the treatment process of extraction palm oil waste (to allow the environmental license) in the development of oil palm agribusiness in the Brazilian state of Para and Peru. A survey was conducted to get some information from the current local farmers and it was also done a historical study on the public policy of tax exemptions, credits and the creation of state institutions or the changes that they experienced, such as the technological changes in this agribusiness. The similar issues found in Para and Peru were: (i) the states with public funds, are those who created this monoculture, (ii) they created organizations/institutions and legal regulations to promote its development; and (iii) at the beginning, tax releases were established to favor only large companies but in recent years these policies allowed direct access to credits to microproducers, it has increased the social base defense of this crop against to opponent ecologist groups. It was found a "predisposition" of the authorities to promote this monoculture and the acceptance of the local farmers due to the permanent "income." It suggested that better public policy in addition to better decisions of the public and private enterprises and the use of superior technology brought together higher production levels of palm oil fresh fruit in Para and Peru, and the increase of planting areas in the last years. Moreover the palm oil waste treatment in both countries is considered as an extra cost and it is only done by big enterprises. It was concluded that the state play the role of player-mediator, which main role was the promotion and development of this monoculture, likewise, the technological development facilitated to the increase of production levels, it supports even more to the promotion of palm oil monoculture in both states.
Acesso aberto (Open Access)
Albedo da cultura da soja em área de avanço da fronteira agrícola na Amazônia
(2010-01) SOUZA, Paulo Jorge de Oliveira Ponte de; RIBEIRO, Aristides; ROCHA, Edson José Paulino da; LOUREIRO, Renata Silva de; BISPO, Carlos José Capela; SOUSA, Adriano Marlisom Leão de
Soybean expansion in the Amazon has been increasing considerably in recent years, the consequences of which can be serious environmental impacts. In this paper the soybean albedo (Glycine Max (L.) Merryl) was evaluated, which was planted in natural field conditions in Paragominas city (PA), a region representative of agricultural expansion in Amazon. A direct relationship was observed between soybean albedo and its leaf area index (LAI), showing a daily maximum value between 0.24 and 0.25 associated to a LAI of 7.17, when soybean has accumulated 1297.62 degree-days. It was found that the most critical phase of the crop, based on change in surface albedo, is the fruitification phase, when albedo shows a maximum mean value of 0.23 (± 0.0007). Empirical models were fitted to simulate the daily variation of the albedo as a function of LAI and soil humidity during the cycle, and to simulate the diurnal variation of the albedo as a function of solar elevation, for each soybean phase.
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.