TECHNOLOGICAL DEVELOPMENTS IN AGRICULTURE FOR SUSTAINABLE IMPACT ON HUMAN HEALTH

Yogranjan , Gyanesh Kumar Satpute, Rakesh Singh Marabi
Department of Agriculture Biotechnology, College of Agriculture, JN Agriculture University

ABSTRACT

Between 70–90% of recent increases in food production resulted from changes in conventional agricultural practices. Pesticides used in conventional agriculture accumulate in the human body and reportedly cause cancer, birth defects, decreased fertility, neurological damage and other health problems. Organic farming systems offer potential benefits to human health through least contamination of chemical residue in food products, reducing farmers' exposure to pesticides and at the same time by increasing the total desirable phenolic content in selected food crops for consumers. During the decade of eighties, preamble of transgenic technology in the backdrop of organic production system has widened the horizon of transforming food production from a chemical – to a biology-based system. Developments in transgenic technology have taken place at input and output traits levels of crop production. Agricultural practices such as organic methods, use of GE plants and selected inorganic conventional agricultural methods can play important roles in future sustainable agricultural practices. In order to let organic and GE cropping systems coexist, strategies must be devised to allow both neighbours to farm in an economically viable manner. These two very different production strategies viz. transgenic and organic production systems will help move agriculture towards a publicly healthy, environmental friendly and sustainable system.

Key words: ecosystem, nutritional health, organic agriculture, sustainability, transgenics.

INTRODUCTION

Sustainability embraces a flexible developmental index of an agriculture production system, from which the population at large derives subsistence health benefits. An agricultural production system is characterized as sustainable under the long term considerations that it enhances and maintains the productivity and profitability of farming in the region. The system conserves the integrity and diversity of surrounding natural ecosystem and improves health, safety measures and aesthetic satisfaction of consumers and producers. Thus sustainable food security will have to be defined as physical, economic, social and ecological access to balanced diets and safe drinking water so as to enable every individual to lead a productive and healthy life in perpetuity [36]. Sustainability rests heavily on the principle of shielding environment; boosting socio-economic equity and nourishing health and hygiene of current as well as future generations. A significantly raised growth rate was achieved during 70s and 80s, while the years of 90s showed signs of recession in food grain production in developing countries of Asia, Africa, and Latin America. Adding to the barriers of agricultural productivity, many new problems related to chemical technologies encompassing irrigation practices and higher input management have cropped up. The demand for healthy food has been increasing at about 2.75% due to increase in population and income [26]. The present article discusses the emergence of negative consequences of green revolution and suggests fast replacement with upcoming technological development. The authors argue the major role of health sector for subsistence benefit in agriculture and emphasize on the cause of merger of organic production system with transgenic technology reflecting an approach of sustainability.

TECHNOLOGICAL DEVELOPMENTS IN AGRICULTURE SYSTEM

Inorganic Production System
Technological inventions and research have changed agriculture in its multitude, but the eternal demand for improved quality and quantity of produce always keeps unlock the room of new interventions. After a particular time period any specific technology reaches a plateau and maintains with diminishing return and falling dividend. The primitive agriculture was based on natural exploitation of ecosystem. The complementary relationship between biotic and abiotic components of ecosystem ended with exponential increase in consumers' population and radical reduction in abiotic matter. The era of green revolution witnessed a quantum jump in agriculture production. During 60s, the application of Mendelian genetics helped the development of dwarf and semi-dwarf varieties of cereals and produced much larger quantities of grains because of a higher harvest index [18]. These dwarf plant types efficiently supported the utilization of externally applied chemicals, as also irrigation water and other inputs. The agriculture grew to be industrial input dependent, mainly fertilizers. Role of nitrogen, phosphorus and potash were considered indispensable with the advent of concept of essentiality and law of minimum. The luxuriant growth of these plant types attracted pests, which necessitated periodical application of chemical pesticides. This era only has brought mechanization to the agriculture sector during the same period. Such improved plant types were subject to rapid propagation through multiple cropping sequences by various technological interventions as exemplified by the incorporation of photo-insensitivity.

The prevailing inorganic agricultural system has led to impressive gains in productivity and efficiency. Between 70-90% of recent increases in food production resulted from changes in conventional agricultural practices [14]. This high production, however, does have negative environmental and health impacts, as well as sizeable consumption of fossils fuels, unsustainable rates of water use and top soil loss, and contributions to environmental degradation, e.g. air pollution, soil erosion, reduced biodiversity, pest resistance, pollution of lakes and streams and over use of surface and ground water [15]. Inputs usage like fertilizers and pesticides consumption, being the utmost components in crop production, has posed much trouble leading to eutrophication and bio-magnification and evoked great human health concern by polluting soil, water and environment. There are a number of evidences which supports the notion that some forms of wild life are suffering due to bio-magnification of chemical residues. Pesticides used in conventional agriculture accumulate in the human body and reportedly cause cancer, birth defects, decreased fertility, neurological damage and other health problems [33]. Reportedly, thirteen insecticides viz. Aldicarb, Azinphos-methyl, Carbofuran, Cyfluthrin, Cypermethrin, Emamectin benoate, Fenpropathrin, Indoxacarb, Parathion-methyl, Profenofos, Tebufenizide, Thiodicarb, Tralomethrin are among the most applied for the management of a single insect species: the bollworm complex. The poisoning symptoms of aldrin, dialdrin and endrine are reported as headache, fatigue, loss of appetite, loss of weight and memory. The same is true with fungicides, even if used judiciously, may pose serious residue problems. Farmers and agricultural workers develop occupation-induced health problems from chemical exposures. Some people working with Captan, Maneb and Streptocycline or in fields treated with either of them showed symptoms of skin irritation and rashes [23]. The use of antibiotics in animals is linked to antibiotic resistant strains of food poisoning bacteria and may cause reduced effectiveness of related antibiotics used to treat humans [13]. The World Health Organization has called for an end to animal antibiotics important to human medicine [12]. While the green revolution is a praiseworthy achievement, the price being paid for it through human lives may come to haunt us if appropriate action is not taken in time to avoid a major catastrophe in the coming years.

Organic Production System
Organic agriculture has its origin in the first half of the twentieth century with the establishment of bio-dynamic agriculture in 1924. Deleterious effects arising with the continuous use of agro-chemicals containing major nutrients, i.e. nitrogen, phosphorus and potassium in large quantities paved the way for deterioration of soil health and in turn resulted into ill-effects on plants, cattle and human-beings. Organic farming is more than just farming without chemicals. Apart from the safe and healthy products, it also takes into account the health of the soil, safety to other flora and fauna, and friendliness to environment [29]. Organic production relies on practices, such as cultural and biological pest management, that can include integrated pest management (IPM) and biological control but excludes the use of synthetic chemical and GE organisms [7]. Organic farming aims at cultivating the land and raising crops in such a way as to keep the soil enriched with microflora and microfauna. Organic system of agriculture production considers achieving nitrogen self-sufficiency derived through the use of legumes and biological nitrogen fixation, effective recycling of organic materials including crop residues and livestock wastes, control of weeds, diseases and insect-pests by means of crop rotations, natural predators' diversity, organic manuring, use of resistant varieties and limited, preferably minimal thermal and chemical intervention. Organic farming systems offer potential benefits to human health through least contamination of chemical residue in food products, reducing farmers' exposure to pesticides and at the same time by increasing the total desirable phenolic content in selected food crops. Moreover, today's concerns have gone beyond producing food that is clean and safe. We need to understand the larger issues such as reducing the trade-offs among food security, climate change and ecosystem degradation.

In developing world, the majority of farming community is dominated by small scale farmers. At the moment "Organic system of agriculture" basically means "for export". It is, not in broader sense, considered as an opportunity for small scale farmers for self provisioning and not to exclusively reach the market. Organic agriculture can be beneficial to small scale farmers without specific inclination of production for export market. It could help their sustenance.

Transgenic technology
Biotechnology could transform food production from a chemical – to a biology-based system. The beginning of transgenic technology dates back to 1983, when it first became possible to genetically modify the plant system. A genetic modification is used in controlling traits of organisms in a way that one manipulation be completely different from another based on traits modified. Intensified efforts in the third world countries are being put on popular application of the technology in selected field and horticultural crops. Tomato, soya, maize (corn), cotton, rape, alfalfa and potatoes are amongst the genetically modified (GM) crops grown most frequently worldwide. Few minor acreage in GE crops are at present commercially successful, i.e. papaya, certain types of squash and sweet corn [16]. GE crops were planted in developed and developing countries in 2007 on more than 113 mln ha worldwide, representing nearly 10% of rain fed cropped area. More than 10 mln of the 12 mln adopters are in developing countries. The adopters are mostly small and resource poor farmers [17]. Despite sizable GE crop acreage, diversity of crop types and traits in commercial production is limited, however proof of concept for many other traits fit into several categories viz. pest resistance, agronomic performance, abiotic stress tolerance, medical applications, biofuels and improved food, feed and environment. Developments in transgenic technology have taken place at two levels of crop production, i.e. input and output traits levels. Input traits related development is the first wave of transgenic technology, which evolved a new level of protection against pests and weed control. Bt cotton substantially reduced insecticide applications over its nine years of commercial use, resulting in a decrease of 11 mln pounds of insecticides. The estimated average 0.1 pound of insecticides applied per acre planted to Bt cotton also takes into account the pounds of Bt endotoxin produced within the cells of Bt cotton plants. Accordingly, the reduction in insecticide pounds applied per acre planted to Bt cotton ranges from 0.46 pounds in 1996 to 0.16 pounds in 2001 [3]. Various prospective studies indicate that the introduction of herbicide-tolerant beet crops could result in savings in the number and quantity of herbicide applications needed for adequate weed control [20]. The USDA national agricultural statistics service (NASS) looked at both herbicide and insecticide use. Active Ingredient (a.i.) used rates for herbicide tolerant (HT) cotton and corn and Bt corn declined from 1996 to 2002 [10]. Overall reductions in pesticides (herbicides plus insecticides) use were observed, as adoption of Bt and HT cotton, corn and soybean increased. This phenomenon led to an overall reduction of approximately 2.5 mln pounds of a.i., although slight increases in herbicide use with soybeans were found [11]. The later increase is consistent with the fact that, as glyophosate application to HT soybean acreage increased, concurrent shift occurred toward less environmentally persistent herbicides [19], such as Pendimethalin, trifluralin and metolachlor [8]. Taken together, these results agree with many field tests and farm surveys showing lower pesticide use for GE versus conventional crops [10].

Technological developments at output traits level are enabling crop production with the incorporation of tailored traits that help in value additions, such as high oil content of corn hybrids with increased levels of amino acids, healthier oils in soybean and nutraceuticals such as golden rice. In the early 90s, efforts involved using tobacco to express a bacterial surface protein to prevent dental caries and to express the hepatitis B surface antigen [24]. Since then maize, potato, rice, soybean and tomato have been used to produce vaccines for both animals and humans [28]. These include subunit vaccines against pneumonic and bubonic plague, shown to be immunogenic in mice [1]; a potato based vaccine for hepatitis B that raises an immunological response in humans [38]; a GE pollen vaccine that reduces symptoms in allergy sufferers [22]; and an edible rice based vaccine targeted to allergic diseases such as asthma, seasonal allergies and atopic dermatitis [37]. Plant vaccines have the advantage of being readily consumed with limited or no processing and of obviating the need for cold storage. "Pharming" has been added to the dictionary of transgenics to indicate a new kind of system to obtain medicine [2]. Results from pre-clinical trials showed that antigenic proteins harvested from transgenic plants were able to keep the immunogenic properties upon purification [27]. Despite various efforts and strategies undertaken by the Food and Agriculture Organization and the United Nation including dietary diversification, food fortification, and vitamin supplementation, approximately 250 to 500 thous. children deficient in vitamin A become blind each year; half of them die within 12 months [25]. Recent studies indicate that bio-fortifica­tion, i.e. incorporating micronutrients through microorganisms into food has potential to control deficiency and is cost effective and efficient compared with alternative public health and agricultural measures [34]. To develop bio-fortification strategies to address vitamin A deficiency, researchers developed the first variety of Golden Rice (GR1), a GE variety with increased level of β-carotene, a precursor to vitamin A, compared with non-GE rice [39]. Golden Rice might increase vitamin A sufficiency for people in area difficult to reach with other vitamin A distribution efforts or for people with limited opportunities to grow or purchase sufficient amount of fresh vegetables or fruits. It is another tool that can be used in public health programme to combat vitamin A deficiency.

Recent revolutions in biotechnology have radically changed the conceptual framework of managing agricultural production system. The use of GE organisms can also contribute to sustainable practices by replacing certain inorganic conventional practices and augmenting organic practices. For example, plants can be created that increase water use efficiency [30], increase no-till or low-till practices [35], help reduce green house gases [9], and produce higher yields without increasing land use [4]. Although GE plants can contribute to a more sustainable agriculture, their development and availability of the seeds to the farmers are least ensured due to predominance of patent laws. Although, perhaps not legally needed, because often no intellectual property restrictions exists in certain developing countries on commonly employed genes (e.g. 35S promoter, hygromycin resistance gene [5]), all companies with patents applying to, e.g., Golden Rice, licensed them at no charge for use in those resource poor countries.

A scientifically sound risk-benefit assessment leading to an objective discussion requires that the various agricultural production systems be objectively compared with each other. Agricultural practices such as organic methods, use of GE plants and selected inorganic conventional agricultural methods can play important roles in future sustainable agricultural practices. A number of arguments reflect incompatibility of transgenic technology with organic system of farming. The amplification of the introduced toxin (high dose) and synergy with the natural toxins and allergens occurring in plants may compromise food safety in ways that cannot be predicted based on the toxicological profile of the individual constituents. Transgenic technology is considered as a threat to the biodiversity of host plant, donor organism and organisms such as beneficial insects and microorganisms that play a vital role in humus formation and cycling crop plant nutrients. The technology invites criticism by promoting selection of resistant target pests by widespread release of naturally occurring toxins in more persistent and toxic forms which particularly indicate the chances of emergence of new pests or weeds not easily controlled through the horizontal transfer of genetic material. Although, those who advocate adoption of organic farming in complementary relation with transgenic technology, consider the later as an extension of traditional plant breeding techniques whereby chemical pesticide is substituted by planting varieties engineered for pest resistance with increased productivity and less organic production and processing costs. The technology itself is based on natural toxins already used in organic agriculture. Both chemical analysis and studies in a variety of animals (e.g. dairy cows, beef-cattle, pigs, laying hens, broilers, fish and rabbits) revealed no significant unintended difference between GE and conventional varieties in composition, digestibility, animal performance and health. In order to let organic and GE cropping systems coexist, the situation where organic and GE crop farming are being practiced on adjoining fields, strategies must be devised to allow both neighbours to farm in an economically viable manner. This can involve altering each other to their plans and modifying them to accommodate each others needs. Where GE crops are cultivated next to organic farming operations, certain practices that minimize synthetic pesticide drift can also limit GE gene flow, such as spatial separation of fields, staggered planting dates and planting verities with different maturity dates and those that are not sexually compatible [21]. Crop must also be segregated during harvest, shipping and processing. Crop specific methods have been devised to aid coexistence strategies. Proper evaluation of the approaches needs to recognize the uncertainty of outcomes, irreversibility of the consequences and the initiative to connect ecological sustainability to social justice. The recognition of such an approach will determine their long-term sustainability and effects on human health and the environment.

CONCLUSIONS

The field of human health is dominated by the health care sector and the task of treating the ill has far more funding and prominence than the responsibilities of preventing illness, creating safe environments and keeping people healthy. Inorganic system of agriculture contributes to poor air quality through pesticide drift, field dust, waste burning, gases from manure lagoons, and diesel exhaust from transporting food over long distances that lead to associated health problems include asthma, cardiovascular disease, lung cancer, and respiratory illness. Residual hormones found in food may be associated with breast cancer and the increasingly earlier onset of human female puberty [32]. Public health is a more likely partner to the sustainable agriculture community than is health care. At least one-fourth of all energy intakes come from food groups that provide large quantities of refined sugar and fat and few micronutrients [6]. Increasing access to healthy food provides strategy with dual rationale to prevent chronic diseases on the one hand and reducing demands on the health care system on the other.

Since their introduction, GM products have been subject to stricter safety regulations and are among the best analyzed of all foods. Their safety in terms of human health must be scientifically verified before their introduction to the marketplace. Organic certification does not imply that foods produced using organic methods are more nutritious or safer than those produced without organic matter [31] and therefore the credibility of organic system to bring about sustainability is moderated. Approved list of chemicals is available for organic agriculture. These chemicals as synthetic pesticides are in practice in organic farming when an efficacious, natural version is not available and no organic substitutes exist [25]. With regard to this aspect of food safety of organics, efforts may be mobilized to replace such list of the chemicals by available GE crop resources. In the interest of consumers' health, products of organic production system should be subject to the same safety analysis as those applied to GE products. Only a flexible and synergistic combination of useful technological approaches and public health policy will enable the existing potential to be fully exploited. These two very different production strategies viz. transgenic and organic production systems will help move agriculture towards a publicly healthy, environmental friendly and sustainable system.

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Accepted for print: 30.06.2010

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