2.2. LA MOMIA EN ESTUDIO
2.3.3 CARACTERÍSTICAS DE LA ENFERMEDAD
C Chemical deterioration Soil pH is outside of tolerable limits for most crops. High concentrations of nutrients (eutrophication) and pollutants are leached, contributing to water pollution and destruction of down-stream aquatic habitats (eutrophication).
Cn Loss of nutrients and/or organic matters Cs Salination
Ca Acidification Cp Pollution
Ct Acid sulphate soils Ce Eutrification
Type 3: IN SITU PHYSICAL DETERIORATION P Physical deterioration
Land/soil capability severely
diminished. Possibility of rehabilitating the land for alternative use is low. Pc Compaction, sealing and crusting
Pw Water-logging
Pa Lowering of water table Ps Subsidence of organic soils
Po Other physical activities (mining & urbanisation)
Source: Ballayan 2004, adapted from FAO (1994) and adapted from FAO/RAPA (1992)
Table 3 emphasizes that issues of soil loss are not only confined to physical removal of soil material but also relate to the soil’s inability to fully function as ‘the planet’s life support system’. The information also reveals dynamism between and among the types of degradation, where a single event can also bring about multiple consequences impacting multiple land-use systems. Systemic impacts are magnified through the soil-plant-atmosphere interactions which, incidentally, are the same mechanisms through which ecosystem/environmental services are supplied. This includes the cycles for producing oxygen and sequestering carbon dioxide and nitrogen. The effects of soil degradation, similarly, affect the plant and atmosphere (environment).
Farming Change, growing more food with a changing resource base 25 A particularly critical issue in land degradation and soil loss is inappropriate land use and soil management practices. Unsuitable land use contributes significantly to soil deterioration and loss, as has occurred in Jamaica and Suriname as a result of mining activities. It also increases the costs of such use since it may require mitigation/counter measures to enhance suitability.
Of all land use changes, construction activities have the greatest potential to produce massive, short- term increases in erosion and sediment.(20) Constructing housing on farm lands will require greater
compaction and bulk density in the soil, more than that available through naturally occurring processes. As a result of the alteration, soil water infiltration and storage capacity are drastically reduced, leading to flooding and terrain deformation. Mitigation measures must be introduced, increasing the financial and economic costs of construction. In recent times, a large portion of erosion in the Caribbean has been caused by poor road alignment and improper control of drainage and runoff from roads. In the late 1970s and 80s, Country Development Atlas were prepared for most, if not all Caribbean countries. These included a series of Geology, Land Capability, Land Use and Vegetation and Land Distribution and Tenure maps.(21) However decisions with respect to land use have generally not been
aligned with capability and suitability assessments. The result has been widespread use of arable lands for housing and other domestic and physical infrastructure.
With independence, economic development and population expansion, pressures on the land for other uses, mainly housing, industrial sites, transportation and other infrastructure have increased. Such pressures have worsened attitudes to land as an inert substrate base, rather than a living resource for productive use.(22) Already, there is evidence of further intensification and diversification of land use to
meet multiple and often conflicting socio-economic and environmental objectives.
Any form of human activity will require some form of alteration of the natural environment. In the absence of countervailing measures, the potential negative effects of degradation are exacerbated. Fortunately, the overall status of soil degradation in the Caribbean is not yet as bad as for the rest of the tropical world; the operative word being yet! This is largely because of the type of soils in the Caribbean and the types of crops being grown. Parent rocks (i.e., the underlying original layer of bedrock) in the region are relatively young, geologically and hence weathering, leaching and soil formation are not very advanced (in general).
20 http://www.cep.unep.org/publications-and-resources/technical-reports/tr2en.pdf 2 Done under an Organisation of American State Economic and Social Affairs initiative 22 www.forestrynepal.org/wiki/4
Critical Issues, Options and Perspectives (CIPO) 2
3.2 Agriculture – a Problem and Solution
Although 99% of the world’s food comes from the soil,(23) the rate of soil loss is greater today than
it has ever been. In fact, an increasing number of scientists are starting to emphasize the extent to which soil – even more than petroleum, water or air – is a limited and fragile resource.(24) (Note
#4). This fragility derives from the fact that natural soil formation processes occur over centuries and soil functions and the scale at which they are provided, cannot be easily replicated using existing technology.
Current estimates suggest that 10–20% of global terrestrial area has degraded soils and there are indications that this area is extending.(25) Back in
June, 2004, the United Nations observed that the world’s land was turning to desert at an alarming speed - at twice the rate that was occurring in 1970.(26) A contributing factor was that
conventional agriculture viewed soil as simply
another commodity, an inert medium for growing. Consequently, soils were inundated with chemicals to provide high yields and kill plant pests and diseases. In the process, once-fertile soils have become severely depleted of organic matter, nutrients and micro-organisms, the army of invisible, beneficial workers in the soil.
Depleted soils are in danger of being blown away by wind or washed away by rain. Consequently, 30% of the world’s cropland has been abandoned in the last 40 years due to severe erosion, and as little as 40 years of farmable soil remain globally. Comparative estimates on the state of degraded soils in the Caribbean are either not readily available or are outdated. However, the well documented experience of Haiti provides a living laboratory and evidence of the possible outcomes from unabated and unwarranted destruction of land and the consequent impacts on soil loss (Note #5). In the Caribbean, Haiti is indeed a special and oft-cited case, in which all the soil resources are highly eroded and important areas salinised.
2 http://www.guardian.co.uk/world/2004/feb/4/science.environment
24 http://www.boston.com/bostonglobe/ideas/articles/200/04/27/the_future_of_dirt/
2 Land Use System Analysis. http://www.alterra.wur.nl/UK/research/Specialisation+Soil+Science/LU/LSA/
2 Source: Bio-Intensive Soil vs Common Gardening Soil from www.greenschool.org/community/green-farm/bio-intensive-soil-vs-common-gardening-soil/
note #4: Soil’s Startling Statistics
For each pound of food eaten in the United States, approximately 5.51 lbs of soil are lost to wind and water erosion, resulting from agricultural practices.
Twelve pounds of farmable soil are similarly lost in developing countries, with 3.70 lbs of farmable soil lost in China for every pound of food eaten. Approximately 213,000 people are added to the planet daily, requiring about 34,000 more farmable acres each day to feed them— acreage which does not exist.
Due to all of the above, by 2014 only about 64% of the world’s population is likely to have an adequate diet. Source:www.greenschool.org/community/green-farm/ bio-intensive-soil-vs-common-gardening-soil/ - - - -
Farming Change, growing more food with a changing resource base 2 note #5:
Soilless Haiti
Substantial soil loss was a problem in Haiti since the colonial period. Mountain forests were cleared for coffee production and plantation crops (cotton, indigo, tobacco) were clean cultivated (scraping weeds between plants and pre-till field burning). Due to excessive erosion, coffee plantations were difficult to re-establish after the first generation and indigo crops were only productive for three years (Paskett and Phylocete 1990).
After the revolution, peasants combined remembered horticultural practices of Africa with learned agriculture and plantation cultivation methods. This produced a mixed system where Haitian farmers would clean cultivate agricultural crops (i.e., removal of bush cover), burn crop stubble prior to tilling and periodically leave annually cropped parcels fallow for an extended period. Tree gardens were also established around family compounds. However, with increasing population and resulting pressures on the limited arable lands, the fallow practice was increasingly precluded, tree gardens were diminished in size, and peasants were forced to move to less desirable mountain lands for annual crop culture and settlement. The increased practice of clean cultivation together with more intensive farming resulted in substantial degradation of the chemical and physical properties of the soil, making erosion all the more frequent. As crop performance fell and lands that had become infertile were abandoned, farming and settlement expanded into the mountain slopes where the disastrous effects experienced in the plains were magnified in the absence of management guidelines for regulating where and how land could be used.
Source: Paskett, C. and Phylocete, C. 1990. Journal of Soil and Water Conservation 45(4): 457 – 459. http://epat.wisc.edu/.forest/.soil-cons/.format/.history.html
The Haiti situation reflects the several significant threats facing other Caribbean countries in particular, the SIDS. Intensive farming systems are, by nature, very exploitive of soil use and over-dependent on agro- chemicals to maintain crop productivity and control of pests and diseases. The urge to continually till the soil and to keep the land free from weeds weakens soil structure and in periods of intense high rainfall and winds, the soil becomes loose and vulnerable to erosion. Similarly, crop production on soils unsuited to farming increases the need for enhancement and mitigation measures which increase costs.
Critical Issues, Options and Perspectives (CIPO) 2
As indicted by the Haiti outcome, poor agricultural practices, combined with land deterioration and soil loss contribute significantly to unsuitable land use. The agriculture problem stems, in large part, from unsustainable patterns of land use.(27) Decades of monoculture, slash and burn and other poor
farming practices were closely tied to the plantation cropping systems, European land law and official land tenure regimes.(28) For agriculture, the best available lands were allocated to concentrations of
sugarcane, citrus, cotton, coconuts, cacao, tobacco and indigo. Food crop cultivation was relegated to the marginal lands, usually on hillsides, the genesis of the shifting, slash and burn substance small scale farming. Intensive farming and other forms of agriculture therefore may be the most liable contributors to inappropriate soil/land use/management and land/soil degradation.
Among the several and significant threats to the state of soil in the Caribbean, associated with the agriculture industry, that further aggravate the degradation process include:
the sub-division of agricultural estates into small plots under independent ownership and control. This policy has exacerbated problems associated with dependency and fragmentation and also placed limits on options for addressing environmental issues,
land use changes, particularly the loss of arable lands to non-agricultural land use, and
soil pollution as a result of inappropriate disposal, including solid waste and mis-use of agro- chemicals.
The issue of soil pollution is of particular interest. Pollution is a sub-type of in-situ chemical deterioration that is particularly destructive on soils (Table 3). Chemical misuse and improper waste disposal of farm materials, such as plastic banana sleeves, agrochemical containers, and over use of agro-chemicals which leach into soils, are major sources of agriculture-related pollutants. This adds to the growing and general problem of pollutants accumulated in land-fills across the region, strained by population growth and increased waste from homes, which are a source of heavy metal contaminants. The impacts on long-term soil fertility, water pollution and eutrophication(29) and sedimentation on coral and aquatic
vegetation are disastrous.
While loss of soil and degradation are taking a significant toll on the Caribbean environment and economy, the situation has not yet received the attention that it deserves. Should this situation of land degradation and soil loss be left unchecked, agriculture and water resources be adversely impacted 27 Land use is the way in which land is allocated and used for a particular purpose. Use is closely linked to soil capability and suitability and is a decisive factor in the ability of soil to resist degradation.
2 Besson, J. 200. Land in the Caribbean: Proceedings of a Workshop on Land Policy, Administration and Management in the English-speaking Caribbean; March –2, 200, Port of Spain, Trinidad & Tobago.
2 Eutrophication is the process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates which typically promote excessive growth of algae.
•
• •
Farming Change, growing more food with a changing resource base 29 but so too will capacity to adapt to climate change and eventually, quality of human life. Farming and food production, especially in SIDS, are already compromised by the impacts of climate change, such as sea level rise and the effect of salinisation on soils and water. This fact alone should raise the proverbial ‘red flag’, and hence the level of urgency with which the region should respond to the soil- loss situation.
The physical quantity of soil/land and fresh water resources is not expected to increase and consequently, the state and future of the natural resources upon which food production systems will depend must feature in this response. However, thus far, Food and Nutrition Security dialogue and interventions are somewhat muted with respect to an explicit recognition of the seriousness of the soil loss situation and definitive actions aimed at mitigating the problem. This appears to be a monumental oversight of modern agriculture and other productive sectors. Such oversight and inaction, amidst increasing loss of arable land, and climate change effects which contribute to desertification, are tantamount to ‘shooting oneself in the foot’ i.e., compromising food and nutrition security and human life.