The agronomist Fernando Penteado Cardoso** affirms that “it’s probable that, in a world with 10 billion inhabitants, the Amazon rainforest will be used as farm land, as humanity is going to need more food, fibers and energy”. This is one of the explosive themes of our interview in this edition on the implications of the future use of part of the earth currently covered by rainforest. Dr. Fernando, as he is known, gained his qualifications in 1936 at the ESALQ – Escola Superior de Agricultura Luiz de Queiroz, Piracicaba, São Paulo state, and graduated top of his class. From a traditional rural family, he has always maintained farming activities, on farmland belonging to his family, to the company or his own. Since his youth, he has displayed a tendency to follow innovative paths. He started working with fertilizers from 1942, and in 1947 he founded a promising company, Manah, whose trademark and slogan – “With Manah Fertilizing Goes”- persists. He has undertaken innumerable professional and business activities, having been Secretary of Agriculture for São Paulo State in 1964. He remained president of Manah, a business that reached second place in the country in finished products, until 2000, when he sold the majority shareholding to the powerful Bunge Group. He surprised everybody, including close friends, when – with everything pointing towards his retirement, after all, he was already 86 years old – together with his wife and children, he started the Agrisus Foundation for Sustainable Agriculture, of which he is President until today, a non profit organization with the objective of encouraging professional training and qualification, research on the productivity of land, recuperation of degraded areas and even a system of direct planting. Since then it has sponsored congresses, seminars, workshops, research field studies, theses, books, as long as they have the aim of spreading knowledge and showing techniques for improving and conserving the fertility of the soil. He has accumulated an enviable level of knowledge about the fertility of Brazilian land, from studies of the cultivatable areas of Brazil and through his wide experience of the Amazonian region, which he has visited innumerable times and where he oversaw the opening of a farm belonging to Manah in Santana, in the south of Pará state. He has written many articles on the Amazon, whilst recognizing that it is a controversial and explosive subject. Dr. Fernando is of the opinion that “our mythologists, in the clutches of mythomania, spend their time mythologizing to create myths related to the Amazon rainforest”.
DBO Agrotecnologia shows some of these myths in this interview-debate, in which Dr. Fernando’s objective opinions are accompanied by comments from the agronomist Odo Primavesi, scientific researcher with Embrapa Pecuária Sudeste, São Carlos, São Paulo state, and one of the 17 Brazilian signatories to the IPCC – Intergovernmental Panel on Climate Change - report. ( Dr. Odo Primavesi’s comments are published in
DBO – What is your view of the Amazon rainforest?
Dr. FC – In the case of the Amazon, the rainforest is the consequence of an environment of warmth and rain on land with sufficient nutrients. It isn’t the cause, it is the effect of the climate and geology. In poor soil, there is no rainforest, but savannahs and native Amazonian grasslands, examples being in the south of Amazonas state to the east of Porto Velho*, - in the native fields of Roraima* and other “spots” of savannah spread across the green continent, such as the ridge between the S. Benedito and Cururú rivers in southwestern Pará.
A large part of the Amazon region is subject to flooding that can last up to 90 consecutive days, other areas are rocky and mountainous, representing an area about 2/3 to 3/4 of the territory, where the potential for farming is almost nil, or extremely challenging. In these areas, the rainforest will be protected by the impracticality of land use. There are several millions of hectares from the Rio Negro and the Solimões/Amazonas basin that, being unusable, represent an economic onus for the country.
Sustainable management of the rainforest, with exploitation of only mature wood, is but wishful thinking, as there has been merciless natural selection over the centuries and the remaining, little developed specimens are those that are genetically less able to compete with other vegetation, and are unlikely to become large and strong trees.
Today’s myths about the forest remind us of previous myths that lasted until the nineteenth century, such as “Heaven on Earth”, “Eldorado”, the “Return of D. Sebastião”, and of the sun revolving around the Earth, among others. Would there have been the civilizations of Europe, North America and the developed areas of our country, if their territories had remained covered by the original forests and they hadn’t been exploited for agriculture, cattle raising and urbanization?
DBO – Wouldn’t transforming the rainforest into farmland alter the rain patterns?
Dr. FC – If the rains originated from the rainforests, they would also be responsible for the waters that run to the sea. Where would so much water come from? The humidity comes from the evaporation of the Atlantic Ocean, forming an immense layer of water vapor held by inertia, which the Earth’s surface slides under due to its rotating movements.
This dislocation from west to east makes the warm and wet atmosphere simulate a east-to-west movement in the form of trade winds, which bring the rain. All the humidity comes from and returns to the sea, after precipitation followed by recycling by evaporation and re-precipitation (2).
The evaporation originates from the moist or flooded soil and from the transpiration of the leaves of the original or introduced vegetation. Nobody knows the proportion of each cause of the evaporation. We have to consider that the subsequent vegetation that succeeds the rainforest – cut-over lands, pasture land, commercial growing areas or reforestation – also show a high capacity for transpiration.
The areas of evaporation represented by the combination of moist soil and vegetation and flooded ground, - which may be responsible for the majority of the evaporation, - are not altered after deforestation. Everything indicates that whether the earth is covered or not by vegetation doesn’t change much the recycling of rain. Some authors calculate that about 50% of the rains come from the sea and the rest derive from recycling.
DBO- Is the expression attributed to the Amazon as “the lungs of the world” valid?
Dr. FC – When the rainforest is at a point of equilibrium, in a state of climax, it recycles carbon dioxide, oxygen, water and other nutrients, without producing them or retaining them. The carbon dioxide absorbed by photosynthesis is recycled through the decomposition of organic detritus made up of fallen branches, leaves and flowers.
If it weren’t for this decomposition, with the absorption of oxygen and emission of carbon dioxide gas, the residues would accumulate year on year, forming a growing layer that would reach the top of the tall trees. These, in turn, if they didn’t lose branches and other parts would reach unimaginable heights, growing non-stop. The state of climax maintains both the height of the canopy and the thickness of the organic detritus covering the earth, in balanced and stable dimensions.
DBO- Are you in favor of burning?
Dr. FC- The pyrotechnic spectacle of fire can result in a negative mental image, different from the reality. The same thing happens with the focal points of heat, large and small, continuous or of short duration, that are detected by the sensors installed in satellites that orbit the Earth, incapable of distinguishing the origin of the heat source.
Fire is a work procedure to destroy undesirable organic residue, such as refuse and organic matter that is hindering agricultural work, like, for example, dry sugar cane leaves, which make harvesting difficult. Piling up the branches after the harvest is very costly, as well as the ridges occupying around 20% of the area for some years, with a reduction in cultivatable space. The only solution is burning.
Some native pastures or even planted areas become very rough and indigestible after maturation, losing their value for grazing. By burning them, new shoots with a high nutritional value grow, which cattle eat avidly.
The tall rainforest doesn’t catch fire, even in the driest of years. The so called forest fires occur in both savannahs and altered undergrowth that have been infested by weeds, when there are parched grasses in the midst of the undergrowth.
The images sent by satellites don’t distinguish the nature of the fire, much less do they have the sense to recognize a barbecue in a back yard, confusing this source of heat with that of an unwanted fire, which is being combated with the greatest effort because of the damage it can cause.
Our bushland and native grasslands have been burned periodically since they came into existence, whether by electrical sparks or human actions. Some species of plants of this biome have adapted to fire, having for example a thick protective bark, or capsules that only release seeds when there is heat from a fire. Fire is part of the climax of the bushlands , considering that part of the vegetation depends on it to reproduce and perpetuate itself.
DBO- How does the rainforest influence the greenhouse effect?
Dr. FC – The current phase of rising average temperatures collected in the two hemispheres is attributed to the rise in the concentration of certain components of the atmosphere. Among these carbon dioxide and methane stand out.
In the first case, the specialists explain that we are releasing substantial quantities of carbon dioxide removed from the atmosphere millions of years ago, and transforming them into petroleum, natural gas and coal. The combustion of these products in the most diverse ways results in carbon dioxide – CO2 – whose concentration is rising in the gaseous mass that surrounds our planet, in which this gas represents only around 36 thousandths of the volume of the atmosphere.
The rainforest in a state of climax, as I explained before, doesn’t contribute anything to this effect. Even cut down and burned, all the carbon dioxide is returned to the atmosphere thousands – not millions – of years later. Although the volume of CO2 released by unit of area of the cut down and burnt rainforest is not clearly defined, what is certain is that, at a global level, we’re talking about values many times lower than the emissions deriving from the burning of coal and petroleum products, including combustion in motors in general.
The emissions from burning are even mitigated by the re-absorption of large parts of the C by plants in growth that succeed the destroyed vegetation, be they cut-over land, pastures or commercial plantations. All new vegetable tissue contains carbon stolen from the atmosphere a short time before through photosynthesis. It’s necessary to remember that the smoke from vegetable products contains aerosols that reflect the sun’s light, minimizing the warming caused by it (3).
Methane has a greenhouse effect many times greater than carbon dioxide. It comes from the fermentation or decomposition of organic detritus, - vegetable or animal - in the absence of oxygen. Hot blooded animals emit methane through their oxygen-free internal digestive functions. As well as intestinal methane, ruminants produce this gas in the anaerobic fermentation that occurs in the rumen, releasing it through the esophagus by eructation.
The principal source of methane is the decomposition of vegetable debris in mangroves, in flood irrigated farm land and in the periods in which the soil is covered with water from flooding. In the case of the Amazon, immense areas with abundant detritus remain flooded annually for long periods. Certainly the mangroves and the submerged detritus are incomparably greater sources of methane than the digestive functions of animals, now and then still not well quantified and certainly difficult to control.
DBO - Wouldn’t transforming part of the rainforest into farmland cause desertification?
Dr. FC – The land in a rainy climate is always covered with vegetation, whose size is related to fertility. Only in extreme cases, such as the sands of Lençóis Maranhenses*, pure silica without nutrients, the situation is similar to a desert, even though in a humid climate.
The Amazon basin doesn’t break this rule: the more fertile the soil, the taller the rainforest, such as chestnut trees, whose size reduces in direct proportion to decreasing fertility, even the grasslands and native fields of Roraima*, of Humaitá* and east of Porto Velho, near the Roosevelt River*.
Itinerant agriculture, which makes clearances when the land becomes infested with weeds, leaves behind new cut-over land, with different forestry re-composition, but rarely the earth is left bare. The use of these lands for grazing results in a declining initial fertility. When used for plantations, the employment of limestone and fertilizers gradually enriches the soil with previously scarce nutrients.
Around the SINOP/ MT* for example, the soil that has been cultivated and fertilized for over 30 years is today much more fertile than in the beginning, or than adjacent virgin vegetation. There are no cases in which the openings have resulted in desertification or “savannahization”, a term used for shrub land vegetation.
DBO – There is, therefore, no risk of devastation?
Dr. FC- It’s a term wrongly used together with destruction, savannahization, as well as desertification, destruction, etc. when you cut down forests to provide space for cattle grazing or farmland. There is no devastation, as, in the place of a poor rainforest, which doesn"t produce anything except wood, economically active pastures or plantations appear, generating wealth and jobs, as happened in the State of Mato Grosso.
STATE OF MATO GROSSO
Change in 27 years
Area planted with cereals.................................1,1 M ha...............7,7 M ha
Production of cereals..........................................1,5 M t..................23,1 M t
Productivity of cereals.........................................1,3 t/ ha................3,0 t/ ha
Bovine stock.......................................................5,2 M head.........17,0 M head
Average HDI of 6 new communities
in north MT*.........................................................villages..................0,800
Sources: CONAB and IBGE- *N. Mutum, Lucas RV, Sorriso, Sinop, Alta Floresta, Matupá.
Estimate of the area incorporated – 6.6 M ha of grasslands (cereals) and 7.9 M ha of forest (pastures)
The sides of the Transamazônica, for example, totaling 150 km to the east and the same to the west of Altamira*, produce annually 40,000 t of cacao (Medicilândia/PA* is the highest producing district in the country), 2 million arrobas (15 k carcass) of bovine meat and varied foodstuffs for 150,000 people, where before nothing was produced, without talking into account the latex many years ago and the removal of wood, which is an integral part of the forest.
The clearing requires a lot of work with the “broca” (the clearing of light vegetation to form kindling for burning), the cutting down with chain saws, the cleaning up of the firebreaks and, only then, the burning after the required time for the branches and leaves to dry properly. It’s a considerable expense that nobody would undertake just to leave the land abandoned.
The removal of the trees to allow light to enter is justified by the fact that there can"t be photosynthesis in the shade of the tree canopy. Since time immemorial, the Indians, and after the Portuguese colonizers, ancestors of the current landowners, carried out successive clearances, be they every 2 years, due to the infestation of the land by weeds, which reduced the area that the family could cultivate. Itinerant agriculture allows the family to earn in order to sustain itself, which doesn"t happen after the invaders cause it to go to weed.
DBO – And how do you explain biodiversity?
Dr. FC – Our tropical and equatorial forests are originally very diverse in terms of the species of vegetation they play host to. It’s a great disadvantage from the point of view of their economic value, as the lack of uniformity hinders their exploitation for industrial uses, such as cellulose, for example.
The natural pine woods of some subtropical regions have a much greater value because of the fact that they are standardized, as well as that they renew themselves naturally. This lack of uniformity can be evaluated using the example of mahogany, whose density is around one commercial specimen for every 10 ha, many times located by air using GPS support, which makes its utilization extremely costly.
Botanists accept the hypothesis that species of vegetation exist with a therapeutic value that hasn"t been revealed yet and a genetic material that could become useful when life science develops and the transposition of genes becomes a routine practice. Talking about hypotheses, everything is possible, which justifies the preservation of botanical forestry reserves in each biome, with reasonable areas, a size and location that allows their preservation untouched, with parallel protection for the existing fauna.
DBO – In the end, is there fertility in the Amazonian soil?
Dr. FC – The Amazon, like other regions, has soils of different classes. It would be a grave error to generalize any concept. Saying, for example, that the soils are fragile, without mentioning where they are located, doesn’t match the reality.
In this vast equatorial region there is land with different characteristics, within 3 basic situations concerning agricultural utilization: 1) swamp lands that stay flooded for long periods; 2) steep and rocky land where it’s difficult to work; 3) high land, not subject to flooding, relatively flat on which agricultural activity is viable.
In this last group, the agricultural lands have natural vegetation differentiated by each class:
1) very poor soil, mostly sandy, with typical bushland vegetation of twisted wood, as in areas found e.g. between the S.Benedito and Cururú rivers, in the SW of Pará state*, between the Madeira and Roosevelt rivers in SE of Amazonas state* and around Boa Vista in Roraima state*.
2) intermediate weak soils, called transition soils, covered by straight-growing wood, easy to remove with chains and bulldozers, which originated the extensive soy bean (OK) plantations in Lucas do Rio Verde and Sorriso in MT state*;
3) land of average fertility, acid, covered by tall forest but lacking the indicator plants of fertile soil, producing rice in the first year, but not corn. Cultivation with fertilizers increases the fertility, as can be seen around SINOP-MT*;
4) fertile soils, less acid, with tall forest with specific indicators such as Para nut and mahogany trees, producing corn soon after being opened. They have been planted with coffee, cacao and rubber trees and teak, as can be seen in Gi Paraná/RO*, in Tangará da Serra/MT* and Alta Floresta/MT* and along the BR-317 in AC*. It reminds us also of the “spots” of black lands of the Indian, rich in humus and phosphorous, originating from lakes where fish perished in drought periods.
Summarizing, in the Amazon there are naturally fertile soils and also poor and average soils that can be transformed into high productivity farming land.
DBO- Is eco-tourism possible in the Amazon?
Dr. FC – Our forests are very poor in terms of variety of animals, except perhaps for some birds, when you compare them to the Pantanal*. Moving through the forest, it’s very rare to encounter any creature, being almost impossible to see it once it hides itself away in the dense vegetation.
In order to see and photograph our mammals, just at night, on top of an uncomfortable platform, next to some food lure. Besides these expectations, it can be frustrating. Also, the forest is humid and rich in biting insects that torment visitors, as much as the ticks that live like parasites on mammals and which easily infest the unprepared tourist.
When we compare the situation of the Amazon rainforest with other regions, such as our Pantanal*, the Swamp Lands of Chuí/RS* or Africa, for example, we need to be realistic about the limitations, not to mention the risk of contracting malaria, leishmaniasis or other tropical diseases, less common in regions with less rainfall or lower temperatures.
DBO - Doesn’t the Amazon forest have riches?
Dr. FC - Except for the extraction of latex at the end of the 19th century and the middle of the 20th century, and today the modest harvesting of Para nuts for 3 months of the year, the contribution that the forest makes to the economy and the well-being of mankind is negligible. The forest is very poor, it doesn’t even offer easy sources of food for the population that lived and lives around it.
Even the Indians, to sustain themselves, cut down trees to allow light to enter and planted cassava, choosing the high vegetation of fertile land that re-sprouted less, required less work to cultivate with the machete and the scythe, after they obtained these tools.(1) The Amazon rainforest, for those who know it, is an immense green desert.
DBO – There is a controversial dilemma in your proposal for the rational use of the Amazon
Dr. FC- The dilemma we face is whether we should or shouldn’t convert to agriculture those 1/3 or 1/4 of the high, flat, well-drained land benefited by a climate of rains and heat, without damaging the botanic and zoological reserves in each biome; if we should or shouldn"t use the greatest natural resource in the country, which is the climate of warmth and rain that benefits huge areas of our territory.
When the world gets close to 10 billion inhabitants, predicted for the second half of the 21st century, perhaps we won’t have any other option, for the sake of national interest, or under international pressure, than to seek food and possibly renewable fuels, that will certainly be demanded for reasons of survival at the desired standards of living.
What is in play today, - with greater intensity in the future-, is the sustainable harnessing of solar energy to promote the process of photosynthesis capable of ensuring the stability of humanity, which depends on the production of food, fibers and energy. Up to today, we cannot promote photosynthesis in the shade of the tree canopy.
We should remember that the so called developed nations substituted their forests for agricultural land and cities and now they don’t have any more space in which to expand. Could it be that we will always have to waste our climatic wealth just because theories from overseas have an interest in maintaining us stagnated with preserved forests on the cultivatable areas of our land? Until when?
Note from the editor:
Some of Dr. Fernando Penteado Cardoso’s proposals in this interview are the same as those that have diligently been the subject of conversations with his 20 grandchildren, with the aim of revealing to them their grandfather’s opinion on the Amazon.
**Senior Agronomist, President of the Agrisus- Agricultura Sustentável Foundation.
*Places visited by the author.
(1) Leonel, Padre João – Treasure Found in the Máximo Rio Amazonas, 1776-
(2) Cardoso, F. – Climatic Futurology, ABCZ magazine, jan. 2007
(3) Lomborg, B. – The Skeptical Environmentalist, 2005, pag. 323