Reflections on Sustainable Agriculture Development

R.L. Tinsley

Introduction

During the time allowed I will try to provide some thoughts on the issues of sustainability as they apply to the smallholder Agricultural Systems in Asia, and more specifically the post harvest handling of horticultural products within those systems. I will attempt to make a conceptual presentation that I hope will be interesting and look at some of the realities and limitations to sustainable agriculture development. My perspective is from a holistic farming systems approach with an emphasis on small holder development. I am an Agronomist who has spent 20 years in small holder farming systems programs with residential assignments in VietNam, Philippines, Sri Lanka, Egypt, Malawi and now Thailand. Between international assignments I am associated with Colorado State University and have spend some time learning Western US agriculture as it contrast with the small holder agriculture of developing areas.

Definition

Without going into specific quotations I would like to use as a working definition for the purposes of this presentation the following:

Sustainable Agricultural is a type of agriculture that provides optimal return with minimum impact on the physical environment or public health.

I realize this is intentionally defined in the vague specific. That is an elegant way of says just enough to be significant but leaving plenty of room for interpretation by anyone so inclined, and thus allows anyone to read into the concept what they like. I hope it does not imply an absolute idea, but more a multidimensional optimization of competing forces with a need for a holistic look at agricultural production at both the local/national as well as the global levels, and all the various trade-off's involved in promoting sustainable development that will assure an adequate supply of agricultural products for the worlds population for as long as possible. Implicit in this definition, if not fully stated, is that sustainable agricultural development will imply a reduction in quality of life at least as defined by the donor economies. This would be initially felt by increase in food and fiber prices from the present 12-15 percent of income and a rippling down impact on the rest of the materialistic needs of the affluent society. While I doubt if most advocates of sustainable agricultural fully appreciate the scale of the quality of life adjustments they advocate, it is something that developed countries can reasonable well afford. However, when applied to developing countries where the issues is still trying to improve the quality of life to a level of an adequate balanced diet and some minor comforts, a reduction in the quality of life is not a realistic possibility, nor is increased expenditures for essential agricultural products that currently consume upward of 75% personal income in some cases.

For the most part sustainable agriculture has come to imply a low input agricultural system with limited, if any, applications of fertilizer or crop protection chemicals. Instead relying of the careful management of crop resides, biological nitrogen fixation, and integrated pest management to provide the essential nutrients and pest protection for the crop. At times it has become synonymous with organic agriculture. How practical this is will be a major part of the following discussion.

Importance of Sustainable Development

While much of this presentation may focus on the problems associated with sustainability along with the limitation and realities it imposes, by no means is it intended to minimize the importance of sustainability and the need to optimize agricultural production while minimizing any environmental degradation. Without producing a lot of facts and figures, I think it is safe to say that world is a very finite place, and while we talk about carrying capacity when we discuss animal husbandry, the same is true for mankind and the capacity of the globe to sustain mankind. Thus the issues associated with sustainable development are of major importance to all of society, both donor and developing alike. The more we promote agricultural efficiency, the longer the global community can maintain and enhance the quality of life and continue to occupy the globe.

Background

The concept of sustainable agriculture was introduced some 12 years ago as a donor country initiative that was subsequently imposed on the recipient countries as conditions for technical assistance programs. Within the donor community, it has served as a valuable means of bring environmentalist/conservationist, whose desire was to protect the environment at all cost with little real appreciation for how sufficient agricultural commodities, which continue to provide the most basic essentials for mankind's survival, were to be produced; into dialogue with the agricultural researchers and producers, who were considered to be the primary source of environmental decline. These groups were, and still remain, somewhat at odds with each other. I think this has more misunder- standing than substance as most of the large farmers I have visited in Colorado with their 2000 ha of wheat-fallow dryland production or 300 ha of fully irrigated lands, are a very environmentally conscience group, who would be severely offended at being accused of not being environmentally active and good stewards of the land. They readily point out they have a very vested interest in preserving their environment as it directly affects their livelihood and very much within their economic time frame. I would also point out that one of the original environment groups, perhaps a half century before the environment movement became popular, was the Soil Conservation Service with it very successful efforts to reduce soil erosion in the USA. However, as the sustain-ag Internet discussion postings scroll across my screen each morning there remains much contention in cyberspace between these two groups.

Within the economic context of the donor community, with their comfortable agricultural surpluses, sustainability is a sound practice and has popular backing by both the general population, environmentalists agricultural producers and supporting persons. For them a modest yield reduction that does not substantially erode farm profits or balances them with increase farmgate prices could easily be absorbed within the domestic marketing system. Unfortunately, few Americans really think beyond their own borders and thus do not consider how essential the USA's agricultural surplus may be for the rest of the world. In this atmosphere the sustainable agricultural movement has spun off some very good, long overdue concerns, and with that some solid research that has changed the way farming is practiced in many communities. Farming has become more efficient with considerable reduction in many inputs including fertilizers, pesticides and perhaps most important, if not usually emphasized, total energy consumption. Much of this has made good economic sense and thus been readily adopted by producers.

As the concepts of sustainability were imposed by the donor community onto the developing community, they were met with considerable mixed thoughts along with some major misunderstandings. The first impression of Dr. Godwin Mkamanda,, former Chief Agricultural Research Office in Malawi, was the darn donors are planning to stagnate agriculture at the status quo. The donor farmers will still hot-rod around with their super 100+hp, aircon, stereo equipped, built-in ice chest monsters, while my poor mom struggles on with her back bent swinging her hoe for a few kilograms of maize and beans while nice red meat meals are an ever receding dream, let alone a rural electric power grid that would allow a stereo, TV or even just a refrige with a nice cool drink. Godwin represents the host country administrator that I have most enjoyed working with in my career, and his mom is just as entitled to a cool drink from a fridge as I am, and any implication to contrary is morally and ethically unacceptable.

That was not really the impression intended, and the concept of sustainability has become reasonable accepted by the recipient community including many Asian countries where, with their growing affluence such issues as pesticide free vegetables are become a substantial concerns by middle class sectors of society. With that introduction I would like to review some of the issues associated with sustainability.

Is Sustainable Agriculture Really Possible?

In its purest form sustainable agriculture would be a complete reversion to subsistence agriculture relying on internal nutrient management within farms without applying any fertilizer or other chemicals. With the world's current population, is that really possible? If you consider that total agricultural needs of food and fiber, including the pulp required for making paper, tend to be fairly inelastic. While there can be considerable elasticity between similar commodities such as rice - wheat - maize - potatoes, or cotton - flax - wool, the total requirements are still so may calories of food per person, and so many meters of fabric, etc. Given that on a global scale our current mix of large high input - high output farm associated with the donor world, and small near subsistence farms associated with the developing world meets the total agricultural demand on a year to year basis with perhaps as little as 1-2% carryover surplus or deficits and many people not really receiving a good balanced diet, and has resulted in essentially all the good arable land, as well as considerable marginal lands currently under some form of cultivation; even a modest return towards more subsistence levels with accompanying lower yields will require more land to produce what is required to meet the world's basic agricultural needs; the land just is not there. Thus, I feel, without going into in-depth computations, that the global community has already exceeded the sustainable limits as defined by the purest sustainable advocates. This is one reason I defined sustainability as an optimizing of two potentially opposing forces in terms of adequate production and environment protection.

Also, while the agricultural needs are being meet, they have been meet by a combination of two very different approaches that has polarized the global agricultural community into one group of large highly efficient surplus producers and the other small holder basically subsistence producers barely able to meet their family needs let alone afford any of the material goods such as Godwin's mom cool drink, commonly regarded as desirable for a comfortable quality of life. There is thus a major need to balance these extremes in agricultural production out in some middle ground.

I also fear the unsustainable imbalance in agricultural will continue as long as the medial profession and related health programs continue to reduce the death rate and extend live expectancies, which is the primary source of pressure on Agriculture as mankind's only "life support system". Under these circumstances true sustainability will remain an ideal to be approached but not really obtainable. For these reasons, those interested in sustainable agriculture must also be firm advocates of family planning as that is the key to stabilizing population and the pressure on the agriculture sector. I am a firm believer that any child brought into this world is entitled to a full healthy life with a well balanced adequate diet. Also, even though complete sustainability may no longer be obtainable, it is a critical target as the globe is a finite resource base that will eventually be overtaxed in both its sustainable carrying capacity and the energy and mineral reserves that are currently being consumed by agriculture.

What comes first? Self-sufficiency or Sustainability?

While the donor community was beginning to focus on sustainability, many of the developing nations were still heavily concentrated on increasing inputs in order to increase yields just to have a self-sufficient agricultural base with which to feed their respective populations and improve the basic quality of life. Thus the questions arise:

Are these concepts conflicting?br Is sustainability a means to allow additional exploitation of the developing world by the developed world?
Which is more important for the ultimate sustained economic development of the global community?
How necessary is it to have an agricultural surplus in order to achieve economic development?

In response I do not think these are necessarily conflicting ideas, it is really a manner of optimizing the production needs and environmental concerns. Many soil conservation practices promoted for contributing to sustainability do have an positive economic return, interest included. However, these tend to be long term returns that may be outside many smallholders economic time frame. I also do not think there is any conspiracy to subject the developing world with another round of economic imperialism exploitation. I would be very upset if this was the case and it would have to come at a much higher level than I and most scientist interact.

Rather I am more inclined to think most environmentalists are rather conscientious in there intentions, just not in-depth global thinkers who are really only looking at their own domestic concerns and immediately extrapolating to developing economies where they really have no conceptual knowledge. I am inclined to believe in the economic axiom that, in the absence of donor assistance, industrial development can only follow an agricultural surplus, as agricultural commodities are essential for sustaining life, and only when there is an agricultural surplus is there both capital and labor available to industrialize. In a recent trip to Lop Buri, my first visit to Northern Thailand in almost 20 years, I think I noticed the impact on Thailand's growing light industry on rural agriculture. The farm size seems considerable larger than my last visit, and with that the medium scale mechanization to operate larger holdings and with this an improved live style that included larger homes, power, TV, pickups etc.

If industrialization proceeds an agriculture surplus, most of the economic gains will have to be exported in exchange for the agricultural goods needed to sustain the populations with little, if any, total economic benefit. Of course there are the Hong Kong and Singapore that appear to be major exceptions to this fact. Although I think it is save to assume that a fairly large portion of there exports are used to import basic agricultural based consumables. Fortunately, a growing number of the sustainable agriculture advocates recognize the self-sufficiency is the higher priority and the production - environment optimizing consideration must be adjusted to that priority. Thus in most developing economies the need to maintain and accelerate the growth rate of the agricultural sector is appreciated, how-be-it with a recognition of the environmental impact of such development and an effort not to degrade the long term returns.

High Input Reduced Area or Low Input Extended Area?

In the totality sustainability of agricultural development, which is going to be more sustainable:

a high input high yielding agriculture on a more limited area, allowing the less desirable land to remain fallow, or developed as green reserves for forest and animal preservation, or

a lower input agriculture that exploits all available land regardless of its suitability for cultivation?

Are these valid trade off's?
Can these two pressures be optimized?

While I think it is politically correct from the environmentalists who are viewing from afar to consider the more subsistence types of agriculture found in Asia and other tropical area to be more sustainable from low input - output consideration, but are they really that sustainable environmentally, and do they provide the minimum quality of life we are willing to accept for ourselves? The slash and burn systems of Asia and Africa in which land is cleared and cultivated for a few years until the productivity declines and than allowed to revert to brush lands for several years to recover. The decline in productivity is normally related to reduction in soil fertility, but I think an increase in weed competition or insect pest like nematodes are equally important factors in the land being abandoned for a fallow recovery. The system is definitely low input, but it is has for many years been considered as environmentally detrimental, because of the erosions problems associated with clearing steep lands, where most of these systems are located, and many efforts have been made to stabilize the land use and population involved in these production systems. Even without the erosion problems, I seriously doubt if these systems are really sustainable. The total cycle has been getting progressively shorter as population pressures in the areas mount. This has been expresses primarily in term of a reduction in the bush fallow period so that the is no longer a complete recovery to original vegetation before the next cropping cycle begins. The incomplete recover then shortens the cropping cycle.

Likewise, the basically subsistence farm family of Africa working with only simple hoes, is more likely in a downward production spiral that in many cases is very much approaching starvation, than a sustainable operation, let alone producing anything near a desired quality of life most of us enjoy. While extra land may be available to a limited extent and perhaps tragically becoming more available as the HIV epidemic takes it toll, a healthy family working with only hoes and other manual tools can only cultivate about 1.5 ha with any reasonable sense of planting time. Animal traction is not readily available in much of Africa because of the tetese fly problems. The returns from a manually operated 1.5 ha, is really not enough to afford the capital inputs needed for reasonable yields increases. Yet, each year the women have to venture further from the homestead in search of firewood, consuming more of the work day as well as denuding ever larger areas, and subjecting them to serious erosion hazards. Meanwhile, the farmers are moving toward more maize monoculture even while straga (the parasitic witchweed that literally strangles the crop) is slowly creeping over the fields further restricting the already low yields, and fertilizer response to uneconomic levels. This is resulting in ever larger areas being grown to late planted sweet potatoes as the ultimate survival crop for subsistence agriculture.

Meanwhile, the African farmer also burn the previous crop residues with the N and some P disappearing with the ash. This is simply because a hoe just can not incorporate maize residue into the soil in anything like a reasonable time prior to the beginning of the following rainy season. The lack of effective stubble management also increases the erosion hazards of the area. Thus both these subsistence systems result in a substantial erosion hazard that is environmentally highly undesirable from a sustainability perspective. In both of these system the inputs are almost non-existent but the production is very limited, and does not provide an adequate balanced diet for the farm household let alone any marketable surplus that could lead to improved quality of life to the level most of us appreciate.

In contrast some of the large farming operations could actually be more sustainable in the global outlook. The large dryland farmers of eastern Colorado are definitely operating with their large air-con monsters spraying 30 meters swath with a single pass. Yet their stubble mulch practices in which crops are directly sown through the stubble without ever plowing and exposing the rolling lands result in less erosion than the family with their hoes in Africa, or the slash and burn farmer in Asia. Most dryland farmers no longer even own plows. Other than the energy and fallow weed control chemicals, they apply very limited amounts of fertilizer or other chemicals, but maintain sustained yields of some 2 t/ha dryland with two crops every three years. At this rate they are capable of providing the food and fiber needs for several hundred people, while maintaining a modest quality of life comparable with the norms of USA society. Perhaps they are not politically correct according to sustainable dogma and considered to be environmentally poor managers, but I would venture they are actually environmentally more friendly and sustainable than our no input highly eroding politically correct subsistence farmers struggling to for a survival level of calories in Asia and Africa.

The input usage and related productivity form a continuum from the purely subsistence with very marginal insufficient returns, to the highly productive fully irrigated farms. As in many cases neither extreme is the most desired, and it is up to planners to determine what is the optimal trade off's between environmental protection and the productivity needed to meet the food and fiber needs for agricultural commodities, and than develop the agricultural polices that will encourage that level of output.

Organic Fertilizer Usage

In the context of sustainable development everyone seems interested in nutrient cycling, manure's, and other biological fertilizers, etc. This is even more so in developing areas where planners and policy makers are looking at reducing the foreign exchange consuming import of chemical fertilizers. However, how practical are they? My first concern is one of the fundamental laws of physics which can not be denied. The law of conservation of matter. That is that matter can neither be created nor destroyed, it can only be changed in shape and form. Thus, except for the biological fixation of nitrogen by legumes or bluegreen algae in paddies, accumulating organic manner as a fertilizer simply moves a nutrient from one location to another within the immediate area with little addition to the total nutrients available within the system. Thus as one areas gain another areas losses. For a small herd of cows to graze a local range land during the day, return to the fold at night, and their dropping retained for fertilizer around the homestead, the grazing lands will be slowly be depleted in nutrients, and with that a slow erosion of the carrying capacity of the range lands, to benefit the homestead. It is doubtful that even, if the range land consisted of well managed forage legumes instead of the normal native grasses, the accumulation of manure would really amount to much. Thus, there is little net nutrient gain to the system. The only gain is the little geologic/pedagogic soil weathering that frees new nutrient elements each year. That is not sufficient to sustain an adequate level of productivity requiring some 100 kg/ha N plus 20 - 40 kg/ha of P & K. Also, there is really very little nutrient value in all this. Considering that the ash content of most biological materials is one percent or less of the dry matter, it is necessary to handle large bulks of moist material for limited nutrient value. This is really expensive, if not in cash at least in terms of labor input for only marginal return. Labor availability tends to be a far more limiting commodity in small holder systems than conceptualized by most agricultural planners and policy makers trying to encourage the practice as a saving to the national economy.

Also, the total amount of organic materials available within a farm community would have the nutrient supply for only a very small percent of the cultivated area, perhaps as low as 10%. I think for these reasons, most composting campaigns have met with very limited acceptance by the farmers despite some rigorous promotion by government extension personnel. More often farmers are more concern with just the physical disposal of residues. With the limited traction power available to most smallholders it is difficult to incorporate the voluminous material like rice straw or maize stover and thus farmers simply burn it to get rid of it so they can proceed in preparing for the next crop. A hand tractor-rotovator or water buffalo and plow just does not have the power to incorporate all the straw produced in anything like a reasonable manner. In my recent visit to Lop Buri I did notice extensive burning of residues even though farm size had increased and most farmers were using small 4-wheel tractors. Rice straw does make a reasonable paper pulp that is blended with wood pulp in several countries and reduces the need for wood pulp. Pulping straw would at least save on forest land and in promote a more sustainable national agricultural sector.

Green manure crops are also difficult to incorporate into the system. There is just not enough time or labor to work with them. Even though many systems appear to have a month or two of slack time at the beginning of the rains prior to planting that should be available for growing a fast cover legume and with that the potential to gain 25 to 30 kg/ha of N or about 30% of the total N needed for a good crop. The realities are that the farmers are really very busy on other parcels of land to take time to manage a green manure crop. The fragmentation of most smallholder holdings make it difficult to observe the entire farm operation at one time. Thus what appears as farmers delaying operations and perhaps avoiding risk, could easily be working very hard to get another parcel of land planted with the limited resources available to them. I feel fairly certain farmers are all to well aware of the potential yield loses for delayed planting and are proceeding as fast as his limited resources will allow. Furthermore, with only hoes, animal, or small rotovator tractors, it would be even more difficult to incorporate the lush residues produced by green manuring then the dry residues of the previous crop. It would be easier to kill the top with a good chemical and stubble plant recognizing that have the N fixed is associated with the roots and thus available underground. Even if incorporated the microbes responsible for the decomposition of the fresh organic matter will utilize the added N prior to making it available to the freshly planted crop.

The same may also be true for agro-forestry programs. Agro-forestry is the process of combining tree cultivation, mostly your leguminous trees, with annual crops with the intention of utilizing the tree products, such as leaves to be harvested annually and applied to the land as a source of fertilizer and possible fuel wood. The most common form of agro-forestry is alley cropping. This is the planting of hedgerows for leguminous trees such as lucenea at about 4 to 6 meters and than planting annual crops between them. It is true that with the use of leguminous trees some nitrogen can be harvested, but I doubt if it will approach the levels recommended for optimal crop production. It is also consuming land both in terms of the land required for the alley and the reduced yield from the shading of the annual crops. In addition it does add an additional managerial component with substantial time commitment to the system. While in Africa there may be some land available for adding tree crops to the system, in many parts of Asia, there is not any surplus land available within the confines of the community to absorb and additional enterprise, even one with some long term sustainable benefits. One village tend to blend directly into the next village with little buffer lands that could be developed. In Asia it would have to restricted to some of the more marginal areas where population pressures are lower.

It should also be noted that leguminous fixation is not totally free. It does require a lot of energy that must come from the photosynthate accumulated by the plant. From the pure chemical perspective it requires a two steps the first is a 7 valence reduction as the N2 gas is converted to NO2 - the nitrite ion, the second a 1 step energy releasing oxidation to the NO3- nitrate ion. Because of these chemical changes most legume will show some response to N fertilizer, but such application will hinder the fixation of N and making the rhizobium bacteria a parasite to the legume crop. While I have no objections to developing and promoting the nutrient cycling, I am somewhat skeptical of the rate of acceptance within the smallholder communities of Asia and if accepted their ability to fully meet the agricultural production targets of National governments.

On the other side, organic farming is becoming very much the politically correct form of farming for the US and other developed areas. I recently visited one such farm with some short course participants. The farm was 1000 ha distributed over some 10 km area just North of Fort Collins, Colorado. It produced a mixture of fresh vegetables that were marketed throughout the US. While they were fully organic with no chemical fertilizer or other non-biological chemicals they made no claims to being sustainable. While they carefully managed their residues, they were highly dependent on neighboring dairy farms and other animal operations for manure and supplemental nutrients. They are inclined to promote a neighboring cow-calf beef operation with all self-contained supplies and good alfalfa forages as the best example of complete sustainability in the area.

Integrated Pest Management

Perhaps the most successful efforts in sustainable agriculture has been the advancement of Integrated Pest Management. Moving away from a total pest kill to a controlled pest population taking advantage of natural control methods has proven to be economically sound and resulted in the reduction of expensive insecticides applications without loosing any yields or quality which is important with many horticulture crops. Instead the attempt is to define an economic threshold of pest population that must be exceeded to justify chemical control application. The reduction in chemical applications also reduce the health hazards associated with direct contact with the chemical. The reduced health hazards are both for the producer who at least in the Philippines have noticed an increase in chronic health problems associated with long term exposure, as well as the residues that are ingested by consumers. The seems to be a rising concern for pesticide free vegetables in Thailand and other more economically advantaged countries in Asia which have a growing middle class that can afford the extra cost of these products. However, with its smallholder agriculture base and the cost of conducting pesticides residue analysis, verifying that vegetables are actually pesticide free is administratively very difficult if not totally restrictive.

In addition to the pesticide management there are also available a number of purely biological controls or product derived natural insecticides. These would include some commercially available bacteria applications, sex attractants, and derivatives of such plants as the neem tree of India. These may not save cost or farm labor for applying, but as natural products they do not consume as much fossil fuels, and as natural occurring chemicals they are normally less hazardous to human health. Other possibilities are growing companion crops with known insecticidal or herbicidal properties. However, these do consume some land and add an additional level of management including labor to the system. They therefore belong to the group of technologies that can be recommended and promoted but may be very slow to be adopted or actually rejected as over burdensome. Acceptance will require a long dialogue with the farmers to understand all the integration problems.

Systems Buffers

As you look at the totally of global agriculture with regards to the finite limits that agriculture can reach and still maintain some level of sustainability, I ask what are the buffer in the system that will allow future expansion of the populations to be provide for. The first such buffer is the luxury consumption of many western agriculture systems. Most western societies including the USA and myself as an American actually have a luxury diet high in animal protein, with much of that in the form of grain feed beef. Consumption of excessive amount of protein normally adds nothing to overall health. Instead the body simply converts the surplus protein to carbohydrate and expels the extra Nitrogen. While ruminants are an excellent animal that can digest grasses and other plant materials not digested by others animals, and thus are able to live on the production of lands not suitable for cultivation; to feed ruminants grain, that can be directly consumed is a real waste of agriculture production potential. When you note that most western grain production goes to animal feed and a large portion of that is for cattle with a 10:1 conversion ratio, there is a lot of surplus capacity in the system. This serves as a system buffer. I will admit that the western diet, in response to health concerns of obesity and cholesterol, is slowly changing away for concentrated on meat consumption to a more balanced approach similar to the Asian diet, which with its normal blend of limited meat protein and vegetables in each dish, is far better balanced between protein and carbohydrate. I fully expect that this in-balance will be somewhat self adjusting as health conscienceness continues to become a major concern in the Western Community and prices for luxury consumption increases.

Another buffer in the global systems is the socially undersirable crops, the most noticeable of which is tobacco. I am always disturbed to see a country like Malawi dependent on tobacco for most of its foreign exchange earnings, or countries who develop vested interest with the tobacco industry as a administratively easy tax base. Likewise I am disturbed to see many young women of both in Asia and the Middle East in recent years express their modern freedoms by taking up the smoking habit. While tobacco is a highly profitable crop that does consume large amounts of the best lands and pushes the more subsistence farmers into the marginal lands for their maize and beans, I like to think that tobacco is a crop with a very finite time limits. As health concerns continue to mount and smokers are more and more being banished to the outer reaches of the work place, people even in the third world are slowing giving it up. As disturbed as I am at the rate young women are picking up the habit, I am equally encouraged by the number of mid-career men who have given it up. I would venture that within the next 20 years there will be a noticeable and permanent decline in the area planted to tobacco. This mostly prime land will than become available for more socially advantageous crops. I also image this will be a market forces driven decline and conversion following the health industry lead and economic cost of tobacco including the high tax most countries place on tobacco products.

The ultimate buffer in the agriculture system may be the root and tuber crops. It is well known that you can get more calories for a hectare of potatoes, cassava or sweet potatoes than from rice, maize, and wheat. This is on a pure dry weight basis taking into account the extra moisture in most tubers. It is just that the reproductive stage, the sex life if you will, consumes too much energy. If you look at history, the white potato with its natural home in the Andes Mountains of South America is commonly referred to as the Irish Potato, because under the repression of British Ireland, the only crop that could come close to allowing the Catholic population to survive was the potato. That was until the potato blight attack and resulted in a major famine and migration. Back to Asia the lowly cassava and sweet potato could gradually become the staple crops of mankind. Their current role as survival crops I think is well known. Cassava being well adapted to some of the poorest soils in any area and sweet potatoes often being planted late after a reasonable estimate of maize crop yields are known. The shift to the root and tuber crops will also be a gradual shift driven by market factors as food prices increase. These crops could also serve as indicators of the nutritional status of the community. The more sweet potatoes in the crop mix the poorer the community and diet balance.

Post Harvest Processing

The prime issue of this short course is the role of post harvest processing in promoting sustainable agriculture development. Not being an real expert in the post harvest processing activities, I can only speculate. My guess is that its biggest role is in recovering and preserving what has already been produced. That is reducing the gap between the biological yield obtained by the producer and the realized yield that finally reaches the retailer and consumer. In traditional post harvest handling of perishable good from farmgate to market the loses have been has high as 50% or more. This has been particularly true for temperate vegetables that are normally grown in higher elevations such as Chang Mai in Thailand, Dalat in VietNam, and Baguio in the Philippines. They are then transported tightly packed in non-refrigerated trucks over pot-holed roads for 6 to 8 hours before reaching their markets in Bangkok, Ho Chi Minh, and Manila, respectively. Under such conditions the 50% loses are unavoidable, just a total waste of good biological production effort.. Some recent packing innovation and organization structuring that replaced disposable bamboo baskets with reusable plastic cartons I think has resulted in substantial reduction of some of these loses. I am currently working with a couple of MSc students examining the transport of tangerines in Thailand and tomatoes in Nepal. One of my concerns in these studies is the ownership and control of the reusable containers. I tend to think the ownership and control of reusable containers may be the key to their acceptance within the system. The further such containers can move along the process the less handling of the goods, reducing the opportunities for bruising the product and the faster it can move through the distribution system. At US$ 8.00 per unit cost for a plastic container that can be stacked when full with out resting on the product, nested when empty with a 2 to 3 year service life; nobody can afford to simply release them into the system and hope they will eventually make their way back home. Some preliminary discussions indicate the containers are owned by the various middle men. This seems logical as these are the people with the most lateral contacts in the distribution system and can directly control the exchange of containers the furthest in what is a multi-staged processing and delivery system. They are also the ones with the most to gain as they normally absorbed the spoilage losses.

The reduction in perishable loses with an open economic system should result in both better farmgate and consumer prices. With this comes the ability to provide more consumable produce from a given area without going into higher inputs. The ultimate results would be reduced area under cultivation for a specific commodity and allowing more diversification, or perhaps a slowing down of expansion in cultivated area. Most of this may actually be overlooked in most system analysis that emphasis the farmgate yield and not the market delivered percent of that yield. It should also be noticed as a reduction in the difference between the farmgate vs. consumer prices. Previously, these loses were adsorbed by the middle men as part of the services they contributed, who are frequently blamed for taking too much profit from the system by those who only looked at the price differential without factoring the adsorbing of the 50% losses.

Promoting Sustainable Agriculture Development

Promoting sustainable agriculture particularly to the small holders of Asia is not an easy task. Many of these farmers are very marginal at best working very close to the optimal their limited resource base will allow, while most sustainable technologies require extra land, effort, or time that probably just is not available to the farmer. The extension effort to inform the farmers should be fairly straight forward and can be rather effectively done. Most extension programs are really designed on the premise that knowledge is the limiting factor and one knowledge is obtained adoption will follow, thus extension programs tend to be good teachers. Extension has more difficulty in dealing with technologies have been taught and then rejected by the farmers. However, with many sustainable technologies once learned be prepared for some major initial rejections. The real problem will be the process of integration into the farming system. That is the process of sorting all the various legitimate factors that prevent farmers from accepting sustainable development. This will mean making certain the required extra labor is in fact available, there actually is enough organic residues to justify the composting effort. Likewise the extra land for something like building leguminous hedgerows needs to be available and not already committed to subsistence cropping. In many intensive farm communities common to Asia, the extra land just is not there.

Another issue could be land tenure. If erosions control measures need to cross farm boundaries it now a community problem rather than an individual farm problem. Addressed from an individual perspective it can be almost impossible to get neighbors to collaborate on these problems even when it is to there ultimate mutual benefit. Among other things it would require getting their crops harvested together so the land will be available for development. Another serious consideration may be economic time frame of the farmer. This the time limit in which the farmers can project to remain in business or survive. If you are promoting something with benefits beginning in three years, but the farmer can only project for one season, than it will be very difficult for him to become interested.

A key factor in most farmer acceptance of sustainable technology will be developing a favorable economic environment. These is really a national policy issue that control prices for both inputs and outputs. These policies really have to take the farmer's best interest into account. Frequently, national policies are designed more to provide low cost staples for the urban areas than provide the producers with good standard of living. Thus the farmgate prices are kept low and public sector infrastructure cumbersome resulting in little fund being available for the long term investments needed for most sustainable technologies. It should never be possible for Cameroon to import rice from the USA cheaper than it can produce and ship it from the northern growing area to the Capital in the south. It was a combination of very inefficient excessive capacity state milling company and poor road conditions. From a long term sustainability of agricultural development these policies are self defeating.

Summary

As discussed above, agricultural has always been and will remain the most important sector of a national and global economy. It provides the ultimate in essential food and fiber for the worlds population. Thus the long term survival of mankind will depend on how sustainable the global agriculture economy will remain. However, in its purest form the worlds population has already greatly exceeded the true sustainable limits of the planet. Thus sustainability has to be an exercise in optimizing mans need for agriculture commodities with the need to protect the environmental so it will continue to provide the necessary biological production. For the smallholders of Asia this can be particularly difficult as they remain primarily interested in increasing productivity to meet individual and national self-sufficiency needs. They are also very much operating at the optimal their limited resources will allow, and thus do not have many of the necessary extra resources to implement sustainable development practices.

Richard Tinsley
Visiting Faculty, Agricultural Systems,
Asian Institute of Technology, GPO 2754
Bangkok 10501
Thailand

Presentation to the Sub-Regional Short Course on Post Harvest Technology, Maruay Garden Hotel, Bangkok, Thailand 8-19 January 1996.

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