Analysis of the Environmental Impacts of Crop and Livestock Activities in the Cerrado and Its Inter-Relationship with Water Resources in the Pantanal
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Analysis of the Environmental Impacts of Crop and Livestock Activities in the Cerrado and Its Inter-relationship with Water Resources in the Pantanal Preliminary version Consultant: Andréa Aguiar Azevedo (ECO/ UnB) Collaboration: Jorge Luiz Gomes Monteiro (GEO/UFMT) 1. Introduction In recent years, an intensive movement has been observed related to the scarcity of water resources. The flow of many water courses, earlier considered unalterable, have arrived at the limit of their resilience1, where they can no longer replenish themselves by natural means. Many springs have dried up due to poor utilisation and incorrect management of these resources. Crop and livestock farming appear as the major activities responsible for the intense degradation of both subsoil and surface waters. The Green Revolution, in the 1980´s, brought new hope to Brazil in terms of agricultural productivity, with high hopes of bounteous harvests and new technologies which allowed the exploitation of little-used regions, such as the Cerrado of Brazil's Centre-West region. In fact many of these expectations were realised, however, the "environmental backlash" generated costs which were often without a solution or unredeemable, as for example, the loss of bio-diversity and the drying up of water courses through silting, in addition to pollution. There are a variety of forms of degradation of water resources by the agricultural sector. In the Upper Paraguay River basin (BAP), bordering the Pantanal, there are regions of the Cerrado bioma much exploited by crop and livestock activities. Intensive use of these mostly sandy soils, combined with poor soil management practices, potentializes a natural erosion process, with silting of the streams of the “planalto” (high plateau), which will eventually affect the rivers of the Pantanal. Associated with the erosion problem is the indiscriminate use of Agricultural Chemicals (ACs), especially in the higher altitude regions, where annual cropping is more intensive, also with unquantified impacts on the Pantanal ecosystem. Efforts have been made to make less aggressive ACs available on the market, but these products are still costlier, and thus less utilised. The inspection and monitoring of the use of ACs are still precarious in Brazil, in spite of "rigorous" legislation. Zulauf (2000, p. 89) warns that independent of the evolution of production technology, the use of ACs is one of the most serious factors in the deterioration in the quality of water resources. Another form of water use, irrigation, among so many other technologies, is capable of increasing production, optimising land use intensity. It effectively supports cropping activities during periods of the year when rainfall is inadequate for growing crops, especially in the Centre-West region. Various aspects of irrigation require examination, such as water use, economic efficiency, the environmental costs of the technology, etc. Studies have shown that, with a water use plan and good management, it is possible to increase crop production taking into account an environmental optimum. This implies respect for the physical limitations of the region which requires a detailed analysis to achieve acceptable levels and impacts on the environment, the main factors to be considered are topography, soil type, crop evapo-transpiration rates, rainfall and others. Irrigation represents the major portion of world water use - about 70% - and efficiency is still very low; estimated average world losses are between 50 and 70% (FAO, 1998, in Rebouças, 2001). Alternatives for a more sustainable agriculture have been researched. Agenda 21, brings out in Brazilian agriculture many of the challenges which the agriculture sector 1 Resilience is the capacity of an ecosystem to regain its original condition or a stable situation, after a de- stabilising event. 1 still has to face in relation to the environment. But much work remains to be done to ensure effective change towards new paradigms for agricultural production. However, the agro-ecosystems should not be managed with the sole objective of conservation of water or other specific resources. There needs to be a systematic vision where all inter- acting elements are utilised in a way that economic rationale is integrated with basic ecological principles. Thus there is a pressing need to protect ecosystems which are notably unique and/or fragile, or to use them with great caution. This study has as an objective to investigate which of the principal ecological processes are being affected in the BAP biomes - Cerrado and Pantanal - by the unchecked expansion of agricultural activities. With this aim, after this introduction, the report is divided into several parts, to enhance its comprehension. In the methods and procedures section, there will be a brief description and characterisation of the study area, the basin of the Upper Paraguay River (BAP). This region was chosen for its immeasurable risks to the water resources, fauna and flora, which form the Pantanal. Within this basin, the principal factors involved in resource degradation, chiefly of the water resources, are concentrated in the upper part of the basin. Here, the Cerrado biome requires priority attention as a means of pre-empting further anthropic alteration. A description follows of the agents which affect the principal natural resources of these environments, deriving from cattle and cropping activities and its sequels. In addition, an evaluation was made of the most fragile sub-ecosystems in the wider biomes, pointing up the possibly endangered species of flora and fauna threatened by the agricultural expansion in the Cerrado. In the fourth section, the impacts of the utilisation of ACs in the agro-ecosystems will be further elaborated, with specific details on the study area (BAP).The fifth section contains an analysis of the present situation of irrigated agriculture in the Cerrado biome, emphasising the Centre-West region of Brazil, within the BAP. The final section comprises an analysis of the principal aspects mentioned in the report, as well as some suggestions for better standards for water users in agriculture and management systems with lower environmental impacts. 2 2. Methods and Procedures This report was carried out with an exploratory search of the bibliography on the subject matter. Priority was given to references having in their scope research on the impacts of crop and livestock activities in the BAP. Studies from other regions were also consulted. A number of interviews2 were carried out with specialists and technicians from private and government entities related to the topic of this research. Also, entities such as the Brazilian Agricultural Research Enterprise (Embrapa) and federal universities were prioritised in the interviews with a number of research workers. Technicians who work directly with farmers were also consulted, since they represent the pragmatic reality of the field. The choice of the BAP is justified by its unique characteristics and, at the same time, because it is an important agricultural region in both Mato Grosso (MT) and Mato Grosso do Sul (MS) states. The juxtaposition of highly productive and profitable agricultural areas and one of the largest flooded ecosystems of the world, with an extensive watershed, besides immense bio-diversity (both animal and plant), makes this an essential and interesting area to study. The BAP has an area of 540,000 km2, with 346,301 km2 in Brazil, covering the South and Southwest of MS and the West and Northwest of MS3. The topography of the region is the same as that typical of the Centre-West. On the flat tops of the plateaux the watershed is not clearly defined, meaning that the watersheds of the different river basins are contiguous. The BAP comprises one large depression, the Pantanal; on the Brazilian side, this is skirted by elevated plateaux, interspersed with depressions. The plateau soils are principally latosols and quartz sands, podsolics are found on steeper lands and the more rugged terrain of the plateau scarps is characterised by lithosols and cambisols (FEMAP, 1999, p. 20). In the Pantanal there is a predominance of gleys and hydromorphic laterites. The tropical humid climate (AW) of Köppen's classification predominates, characterised by a summer rainy season and dry winters. The temperature increases from South to North in the BAP. Rainfall is heaviest at the Northern extreme of the basin, exceeding 2000mm in places, while in the South, in some of the depressions, only 1000 mm/yr average precipitation is recorded. The population of the BAP comprises 1,839,050 inhabitants, covering 76 municipalities (31 in MS and 45 in MT); the largest urban agglomerations are formed in MT, including the capital, Cuiabá. 2 See Annex I for the list of names. 3 The national Water Agency gives a figure of 363,592 km2 3 3. Agriculture and Natural Resources From its beginnings, the conquest of nature by man, transformations began in the environment - agriculture is a notable form of appropriating nature's space. Using the concept of ecological sustainability4 in the strict sense, it could be said that at this point the environment was already affected. In order to utilise his abilities and fulfil his desires, man has to exploit nature. The big problem has been the way is which he did it. In order to develop, man completely ignored that he too is subject to nature. The discipline of ecology has long since raised the alert about resiliences in ecosystems, but only when the science of economics (in the domain of the humanities) signalled that this forma of exploitation was beginning to be "expensive", did those directly involved in the use of natural resources begin to pay attention. This scenario could be found in any production area, but focussing on agriculture, it can be observed that farmers and government took a long time to perceive that the mode of exploitation of agro-ecosystems could be, in many cases, unsustainable through exhaustion of natural resources, such as water and soil, which are the most directly involved in this type of production activity.