|Livestock Research for Rural Development 24 (10) 2012||Guide for preparation of papers||LRRD Newsletter|
According to current trends, experts predict that over nine billion people will inhabit our planet by the year 2050. The question naturally arises: how do we go about feeding nine billion people?
In many developed countries, food accounts for 10 to 12% of the household budget. Yet in countries such as Egypt, food costs comprise more than 40% of the household budget. In India we see even bleaker statistics: over 40% of the children under the age of three are undernourished and underweight. In Spain, hit hard by austerity measures, a relatively large number of people regularly forage through garbage bins in search of their next meal.
Looking back over the last five years, we cannot help but conclude that we are in the midst of a global food crisis, and this crisis, according to the investment banker, Jeremy Grantham, is not going away any time soon.
Global grain prices have almost tripled within the last 10 years. But listen to this: during the summer of 2012, the price of corn, wheat and soy rallied 30 to 50%, despite heavily increased planting since 2008. If grain prices were merely to double within the next 20 years, hundreds of millions of people world-wide would starve.
Water is a finite resource, and it’s getting scarce. About 300 million people in China and India are dependent on aquifers that will soon dry up. Phosphorous too is a finite resource, and as much as 70% of all high-quality phosphorous lies in the hands of one country - Morocco. In a few decades from now, this hold on phosphorous could be, as Grantham explains, “the most important quasi-monopoly in the history of man!” Pesticides, herbicides, chemical fertilizers and excessive levels of tillage are destroying the fertility of soils. More than 25% of the land in China has already become unfit for agriculture.
In 2010, we experienced global weather patterns of heat, drought and flooding that take place once every 150 years. In 2011, we experienced global weather patterns that take place once every 50 years. Now in 2012 we see weather patterns that come along once every 20 years. When there are three extreme years like this back-to-back, we cannot help but feel that our entire weather modeling system has unraveled. The only explanation for such off-the-chart patterns is global warming.
Northern ice is melting far faster than anyone could have predicted. It’s already at levels forecast for the year 2050. As ice melts, less heat is reflected into space, greatly increasing the rate at which ice melts. As heat rises, tundra melts, releasing large amounts of methane – a greenhouse gas 21 times more damaging to the environment than carbon dioxide. Two run-way cycles of warming spell big trouble for grain production. Rising temperatures in the next few decades are projected to reduce the productivity of grain in traditional areas by 20 to 40%.
More and more people in developing countries demand greater quantities of meat in their diets. But producing meat is not terribly efficient. It takes 30 kg’s of grain to produce one kg of dressed beef. But how to produce more grain when top-producers of wheat in Europe as well as top-producers of rice in Asia have failed in the last ten years to increase productivity? And don’t forget the 1.3 billion cows on our planet that emit a lot of nasty methane.
There are a few simple things that we might do. We might eat less meat, especially beef. We might stop wasting food (one third of food produced globally is wasted!). And the United States should immediately stop making ethanol from corn. The ethanol industry in the USA consumes 40% of its production of corn, and through substitution, this practice raises the price of most other grains. One gas tank of ethanol can displace enough calories to feed one poor person in India for an entire year.
In addition to making some tough choices aimed at limiting population growth, we must look for solutions that address core issues relating to sustainability. A process can only be viewed as sustainable insofar as the waste it generates is transformed and returned to that process.
Therefore, the key to the sustainable production of food lies in the transformation of all of the waste surrounding the production, preparation and consumption of food – rigorously coupled to the return of all transformed products back to agriculture (in the broad sense). Put in the simplest of terms: if it comes from agriculture, it has to go back to agriculture.
I would like to highlight four types of waste along with a few simple methods (among many) of transforming them into valuable products:
|Types of Waste||Methods of Transformation||Products|
1. high nutrient content
|pasteurization, drying, cooking, fermentation||feed|
|2. medium nutrient content||black soldier fly and red worm bioconversion||feed/fertilizer|
|3. low nutrient content||thermophilic and mesophilic bioconversion||fertilizer|
|4. little nutrient content||gasification||fuel|
Remember, one third of food produced globally is wasted. A large portion of this waste can be processed as type 1 waste. Here we might also situate slaughterhouse waste, shrimp waste, fish by-products, fish mortalities as wells as a lot of fruit and vegetable waste coming from farms, markets, supermarkets, packing houses and food preparation facilities. The idea here is quite simple: if waste has a high nutrient content, preserve it as a feed.
A lot of type 1 waste could be pasteurized, cooked or dried, but this waste often turns bad before it can be processed in these ways. Also cooking and pasteurization demand fuel, and why waste fuel, if there is a simple way to avoid the use of heat? This brings us to an ancient way of preserving nutrients: lactic acid fermentation.
Here lactic acid bacteria consume water-soluble carbohydrates and produce lactic acid. As the pH drops below 4.2, (sometimes as low as 3.2) the waste is thoroughly pasteurized. With the addition, often times, of no more than about 5% molasses by weight, nutrients can be preserved for an indefinite period of time.
On the simplest of levels, a plastic sack or drum is all that is needed for both processing and storage. Both sack and drum cost very little, and they can be used over and over again. Lactic acid fermentation works on a large variety of waste materials, even shrimp shells and dead fish. Complete pasteurization takes place. Proteins are not denatured as when heat is applied. Fermentation might require a bit of chopping, mixing and blending, but it is no more complicated in principle than the fermentation of vegetables for human consumption. Once the recipe is known for a particular type of waste, almost anyone could become an expert in fermenting it. As a mono-gastric and omnivore, the pig excels as a recipient of the feed produced at this first level.
Type 2 waste consists of fresh putrescent waste that cannot be preserved as feed and yet is still too high in nutrients to be composted as type 3 waste. Examples of type 2 waste are pig and cow feces. When this waste is subjected to the combined action of black soldier fly larvae and red worms, we see one of the most efficient nutrient extraction and conversion processes on our planet.
BSF larvae digest fresh fecal material, something that red worms cannot do, and red worms digest the more recalcitrant cellulosic materials within the fecal material, something that larvae cannot do. Together they form a perfect partnership recovering all possible nutrients. Note well that the waste here is digested twice: first by larvae and then by red worms. Red worms grow two to three times faster on BSF residue than on many of the waste materials normally fed to them. The larvae and red worms are exceedingly nutritious and are an excellent replacement for fish meal valued at over $1,000 US/ton.
BSF larvae are some of the most voracious eaters found within the natural world. In an area of only one square meter, they can eat up to 25 kg of fresh putrescent waste per day. They can digest food waste that is far too toxic to feed to pigs or other animals. It takes them roughly two hours to die when submerged in rubbing alcohol. They can be centrifuged at 2,000 g without harming them in any way. They are tough, robust and adaptable.
BSF larvae thrive on all types of fresh fecal material. To these hungry larvae, pig feces have roughly the same nutrient value as food waste. Dr. Craig Sheppard of the University of Georgia demonstrated that 18% of the weight of fresh pig feces is transformed into fresh BSF larvae. On food waste in the USA, by contrast, the percentage of conversion fresh-to-fresh is no more than 20%.
BSF larvae contain a lot of high-quality nutrients: on a dry basis, about 42% protein and 35% lipids. The big value here is in the lipids. They contain about 54% lauric acid. Coconut oil by contrast contains about 50% lauric acid. About 3.5% of the calories found in human breast milk is lauric acid, and it is the main antiviral and antibacterial substance found there. Lauric acid is active against lipid-coated viruses, including HIV and measles, as well as many pathogenic protozoa and fungi.
The monoglyceride of lauric acid, known as monolaurin, has profound antiviral and antibacterial activity, as explained in A Review of Monolaurin and Lauric Acid. It is not clear just how humans and animals produce monolaurin from lauric acid. This amazing mono-ester kills several types of pathogenic bacteria that are resistant to antibiotics, and yet it does not appear to have an adverse effect on gut probacteria. In sum, it effectively combats many gram positive bacteria as well as a long list of deadly viruses. Several lauric acid mono-ester formulations even prove to be effective against MRSA, swine flu and bird flu.
Generally the larvae and worms are far more nutritious than any of the transformed products of type 1 waste, and the residue of the red worm (vermicompost) is far better than any of the transformed products generated at level three. Vermicompost is at least 4 times more nutritive than conventional composts, and it gives 30% to 40% higher plant yields over chemical fertilizers. This is explained quite convincingly in this excellent paper on vermicomposting.
Ideally we should not feed type 1 waste to type 2 transformers (except of course when type 1 waste turns bad and toxic). Nutrients are lost at each trophic level introduced. Likewise we should not feed type 2 waste to type 3 transformers. And finally in an ideal world, we should not take type 2 waste and transform it into fuel (biogas), since type 2 products (larvae and worms) have a far greater value than biogas. If it’s fuel we need, we should turn to type 4 waste, as will be explained shortly. Whenever possible, wherever possible - since we are in the midst of a global food crisis - our overriding goal should be to maximize food production.
The third type of waste is easily transformed by thermophilic or mesophilic microorganisms (mainly bacteria and fungi). Generally thermophilic composting is quicker and more efficient than mesophilic composting. But the latter is needed when the quantity of waste produced is too small to be collected and processed on a frequent or regular basis. Through mesophilic storage and reduction, the daily collection and land-filling of household waste can be entirely eliminated. In this way, all of the biodegradable waste from the farm that makes it into the household can be transformed and returned to the farm. The residue of mesophilic bins, once reduced to an appropriate grain size, serves as an excellent substrate for red worms.
This logic should be extended to include the whole of human waste.
On a yearly basis a human produces roughly 500 liters of urine and 50 liters of feces. These two products contain enough nutrients to grow all of the grain that this person needs as food. But instead of utilizing these 550 liters as a resource, we do something amazingly foolish: we mix it with roughly 15,000 liters of water, and all goes down the drain. This end-of-pipe solution recycles nothing. It takes valuable resources and transforms them into pollutants.
As fertilizer prices rise throughout the world, and as water becomes an increasingly scarce commodity, this unsustainable approach makes absolutely no sense. We cannot continue to produce nitrogen fertilizers from fossil fuels and phosphate fertilizers from phosphorous-bearing rocks. Phosphate reserves are rapidly dwindling and increasingly contaminated with pollutants such as cadmium. In as little as 25 years, apatite reserves might no longer be economically exploitable, and some predict that massive world-wide starvation will follow.
If we are serious about achieving full sustainability in this regard, we should not mix urine with feces. Within the human body these two wastes are produced and stored separately, they are excreted separately, and afterwards they should be contained and processed separately. A double-outlet toilet, one for urine and the other for feces, is all that is needed. The feces receptacle, except for the lid, is the same device used for the mesophilic storage of household biowaste.
In tropical and semi-tropical countries, the feces storage bin is inhabited by BSF larvae within about 15 days after its construction. BSF larvae eat human feces within an hour or two after it is introduced. This is a powerful factor in eliminating odor. These incredibly active larvae also keep the contents of the bin well aerated. Biochar and effective micro-organisms can also be added to the storage bin from time to time to further eliminate odor. The residue of this bin should be fed to red worms. They have the means to thoroughly sanitize it.
Most of the nutrients absorbed by the human body from food are excreted in the form of urine. The nutrients in urine are easily taken up by plants. Generally the urine of one person is enough to keep 300 to 1,000 square meters of agricultural land well fertilized.
In Vietnam, farms are typically small. The average size of a farm in the Mekong is 1.2 hectares; while in the Red River Delta it is much less (Farm Size and Land Use Changes in Vietnam). If all of the urine produced by an average farming household were diverted, collected and directly applied to the soil, this alone would effect a significant reduction in fertilizer use. In addition to the direct application of urine to the soil, there are many other ways to conserve and utilize the nutrients within human urine.
We talk a lot about sustainable food production, but we will never achieve true sustainability in this regard if we ignore the importance of every gram of human waste produced world-wide. Imagine what marvelous things could be done with the waste of nine billion people! Giving back to nature all of the nutrients within our own waste is perhaps our first and most important duty as citizens of planet Earth.
Finally there is lignocellulosic material (type 4 waste) that does not decompose very easily. Good examples of this are the rice hull and the coffee husk. These recalcitrant materials can be transformed quite inexpensively in top-lit, updraft gasifiers. The economics here are quite unbelievable: one ton of rice hulls acquires a value in syngas and biochar of almost $300 US. This means that one ton of rice hulls has a higher value on average than one ton of paddy rice. The line between product and by-product becomes blurred. Nothing in terms of solar or wind power comes even close.
v Without a pot, the flame looks like this.
v With a pot, it looks like this.
The biochar produced in these gasifiers has excellent cation exchange and water-holding capacities. Biochar aerates the soil, and once in the soil, it does not easily degrade. A substantial portion of it remains there for hundreds, if not thousands, of years. Its incorporation into the soil is an excellent way of sequestering carbon (Bio-Char Soil Management on Highly Weathered Soils in the Humid Tropics). Like worm castings, biochar promotes the growth of beneficial soil microbes and greatly reduces the need for fertilizers. Biochar is used extensively in the reclamation and regeneration of soils degraded through the use of chemical fertilizers. Rice hull biochar with a bit of compost has been shown to increase rice productivity in degraded soils in Cambodia by as much as 300%. The addition of rice hull biochar increases substantially the yield of water spinach (paper 1, paper 2 and paper 3) and maize. Anyone doubting the benefits of biochar should go the website of the International Biochar Initiative.
Dr. Thomas Reginald Preston has done important research in demonstrating that biochar could play an important role in the reclamation of about two million hectares of acid sulfate soils in Vietnam located in both the Red River Delta in the north and in the Mekong Delta in the south. These soils tend to be quite acidic, and consequently the yield of many crops grown on these soils has declined substantially. Two million hectares represents about 21% of the land in Vietnam currently used for agriculture.
Dr. Preston demonstrated that when rice hull biochar is added to these soils, normal plant growth and yield are obtained. Because Vietnam’s security in food production comes into play, he states that the reclamation of these two million hectares is not a luxury but a necessity. The gasification technology described in this essay is inexpensive, and Vietnam has enough type 4 biomass to carry out this reclamation in a relatively short period of time. There is no greater advocate of sustainable agriculture than Dr. Preston. The thousands of articles that he has authored, co-authored, mentored and inspired are an incredible resource for anyone interested in sustainable agriculture.
The small-scale gasification of biomass is a powerful concept (see this short essay), and this technology should be engineered for widespread use even in the developed world. Alongside microwaves and toaster ovens, there is definitely a place for gasifiers in modern kitchens. In large portions of the developed world, the wood pellet, derived primarily from forestry waste, becomes the obvious source of gasifier fuel. No one, rich or poor, either in developing or developed countries, should rely exclusively on fossil fuels to cook food or boil water. Hopefully within the next ten years, engineers throughout the world will give small-scale gasification the attention it deserves.
This listing of the types of waste, as well as the means to transform them, should not be viewed in a rigid and definitive manner. What needs to be emphasized, above all else, is that there should not be a single approach to waste transformation that overrides all other approaches. It is precisely the integration of many waste transformation technologies that results in the most beneficial environmental impact and the highest economic return. We must remain open to multiple approaches and to whatever works best in a particular situation. For example, certain agricultural residues, such as wheat and rice straw, defy easy categorization and can lead us in many exciting directions.
There’s money to be made in growing mushrooms on straw. Nothing could be better than this, for the main product of this fungal transformation is food for humans, while the mycelial residue can be fed to larvae and/or red worms. There’s a limit of course on growing mushrooms for human consumption, and when this limit is reached in a particular area, one might focus on the cultivation of mycelial biomass solely as a substrate for larvae and red worms. Here fairly worthless straw is converted into two living creatures of exceptional value.
Straw can be used as cattle feed. But since it only contains 3% to 5% crude protein, such feeding makes sense only if supplements are added. Straw can be pelleted and used as high bulk density bedding for animals, and this urine-soaked bedding can eventually serve as a substrate for red worms. Straw can be shredded and composted thermophilically along with materials of a low C:N ratio. And finally straw can be pelleted to serve as gasifier fuel. The compost, vermicompost and biochar from all of the above processes can be mixed together in the right proportions to form an exceptional growing medium for plants.
From this one agricultural residue we can produce food, fuel, feed and fertilizer, and the tonnage of straw produced globally each year is phenomenal. The transformation of straw could become a global business worth hundreds of billions of dollars US each year. It seems that agriculture has yet to learn the enormous value of the many types of waste it generates.
But if we really want to produce a lot of food, it’s not enough to focus on how to transform waste and route it back to agriculture. We have to take things one step further. This next step is best explained by means of an example - an example that I often use when addressing farmers in the south central highlands of Vietnam.
There’s a coffee farmer who typically grows nothing but coffee, and right next door, there’s a pig farmer who only raises pigs. The coffee farmer dumps coffee pulp and coffee husks into a valley near his farm, and is totally reliant on chemical fertilizers; while the pig farmer flushes pig waste into a nearby stream, and buys all of his feed from Cargill.
In contrast to this total nonsense, let us imagine that the coffee farmer is at the same time a pig farmer. Instead of dumping coffee waste in valleys, he ferments it and feeds it to his pigs – pigs located on the same farm where his coffee is cultivated. The crude protein content of fermented coffee pulp is about 14%. The feces from his pigs are processed by larvae and red worms, and the urine from his pigs flows into a granular bedding laced with biochar (this bedding could even consist of dry coffee husks). As the pigs mature, the bedding is slowly transformed into valuable compost. This strategy eliminates the odor, flies and virtually all of the disease normally associated with raising pigs. The vermicompost and mesophilic compost are then used to fertilize the coffee plants. The yearly income from the sale of pigs eventually matches, and at times surpasses the yearly income from the sale of coffee beans.
The farmer understands what lauric acid can do for his pigs. He feeds small amounts of coconut and BSF oil to them each day. The pig metabolizes lauric acid to produce antibacterial and antiviral compounds that effectively combat an array of swine diseases, especially those caused by bacteria such as MRSA and Clostridium difficile. At his farm, pharmaceutical companies pushing antibiotics have nothing to sell.
Let us suppose further that this same farmer plants perennial peanut (Arachis glabrata) throughout his coffee plantation. This beautiful, lush ground-cover controls weeds, prevents erosion and fixes nitrogen. Earthworms proliferate in this nitrogen-rich environment, and as they burrow through the soil, they eliminate the need for tillage. The farmer introduces free-range chickens to forage on the perennial peanut. They feast on insects within the peanut vines as well as on the live larvae and red worms cultivated on pig feces. The yearly income from the sale of free-range chickens eventually matches, and at times surpasses the yearly income from the sale of coffee beans. Chicken droppings continually fertilize the coffee plants. In between the coffee and perennial peanut, the farmer plants taro as an additional source of fermentable biomass for his pigs.
The coffee farmer soon realizes that, in order to have a more regular supply of fermentable biomass for his pigs, he should also cultivate bananas on the same farm. After the banana fruit is harvested, the farmer chops and ferments the massive pseudostem of the banana plant. The farmer gradually expands his efforts in the direction of rabbits, which also forage on the perennial peanut, and in the direction of bees, which feed upon the nectar produced by the coffee and peanut flowers. The farmer then stocks his irrigation pond with ducks and fish.
Next he installs on his farm two top-lit updraft gasifiers: a small one for all of his household cooking and hot water needs, and a larger one initially for the distillation of rice wine (the mash is fed to his pigs). His total investment in gasifier equipment is less than $100 US. He gasifies, of course, the dry coffee husk, which he has in abundance. He stops buying bottled gas altogether.
He then realizes that he can use gasifier heat to dry the coffee cherry and even the more delicate coffee bean. In this way he is no longer so dependent on sunshine, which is often unreliable, especially if the dry season is late in coming. This eliminates spoilage due to fungi and mold. His coffee dryer together with gasifier might look like this.
He ends up with a lot of coffee husk biochar - a biochar quite rich in potassium. This biochar has roughly the same volume as the original coffee husk gasified. He mixes some of this biochar into his fermented pig feed, he mixes some of it into his pig bedding, and he uses some directly as a soil amendment around his coffee and banana plants. Finally he sells some of it at a high price. The moment he starts selling biochar, (just imagine) he becomes a consumer of energy at a negative cost.
So the one farmer ends up cultivating a variety of plants, animals, poultry and fish. They all complement one another in increasing efficiency, reducing cost, maximizing profit and minimizing environmental impact. Note that the one fairly uneducated farmer produces with ease the four basic commodities of food, fuel, feed and fertilizer. This enables him to make a lot more money per hectare than any conventional farmer in his area.
Big Ag and Big Oil come nowhere near his farm. He finally breaks free of the commercial slavery they impose upon hundreds of millions of poor farmers throughout the world.
Farmers world-wide should be taught the ancient wisdom of raising plants to feed animals and animals to fertilize plants. In such a strategy, all waste by-products become essential inputs. The imbalance created by the continuous outflow of food products that the farmer brings to market is corrected in large part by the continuous inflow of materials that the farmer receives from mesophilic bins, urine-diverting toilets, gasifiers, as well as small-scale composting and fermentation facilities.
The farmer can grow two or more plants in proximity to one another in such a manner that they do not compete in terms of physical space, nutrients, water or sunlight. Such biodiversity is important in limiting the outbreak of crop pests and diseases. Beneficial insects, earthworms and other beneficial soil organisms thrive in such an environment. They limit the proliferation of harmful insects and soil pathogens. Pesticides and herbicides are no longer required. In any one space and at any one time, a lot more is grown, harvested and sold.
The farmer does not manage a single crop such as coffee or bananas. Rather he manages relationships between living systems that mutually support one another. The ability of a plant or animal to enhance the growth of something else becomes paramount in agricultural planning. This approach enables the farmer to have a highly diversified basket of products that protects him against market fluctuations and assures a predictable and steady stream of income. His strategy resembles that of an investment banker who always maintains a well diversified portfolio for his clients. The farmer’s annual revenue and profitability per hectare, therefore, is at least three to five times more than that of a conventional farmer.
On the one hand, some might argue that these ideas are too brain-intensive for the average farmer in developing countries, and that it would take an army of agricultural extension agents to train and advise farmers in all of these technologies and strategies. But the economics of sustainable and diversified agriculture are so appealing that agricultural extension agents would not be required.
Here we might call upon brokers who are at the same time social and environmental entrepreneurs. They would contract farmers to grow plants and animals on their behalf. They would supply equipment and training to each farmer. They would buy at fair market prices all that the farmers under them are contracted to produce. Each farm would remain small and intensive, while each broker could operate in partnership with a large number of farmers.
The broker would also certify to the consumer that all farm products conform to the highest standards of sustainability. Brand names (such as Highland Pork or Highland Eggs) would be established by each broker, and brokers would vigorously compete with one another in offering consumers the healthiest and tastiest farm products.
On the other hand, someone might argue that these ideas are only for relatively poor people in developing countries. But they overlook the fact that most urban agriculturists in the USA clearly understand the benefits of an agriculture that is small-scale, intensive and local. This new generation of young farmers has the brain power to totally reinvent agriculture in the context of a developed world where labor is not cheap. They sell directly to consumers and do not need to go through middlemen or brokers.
Rich or poor, developed or underdeveloped, it makes no difference. Waste transformation and polyculture are not optional. As the price of fertilizer derived from fossil fuels continues to rise; as phosphorus becomes increasingly contaminated and expensive; as the cost of importing grain and other feedstuffs from America and Brazil becomes prohibitive; as our oceans become critically depleted and can no longer provide the protein needed to make feed; as the price of oil rises above $200 dollars a barrel; as farmland becomes contaminated with chemicals, depleted of carbon and thoroughly unfit for cultivation; as hundreds of millions of people world-wide begin to starve and die; as food insecurity increasingly undermines the stability of nations – such an approach becomes an absolute necessity.
To understand what farming should be, we should deeply reflect upon the rich diversity within the natural world where a large numbers plants and animals within an ecosystem mutually support one another, each occupying a niche that is spatially or temporally distinct. Once we understand that in nature there is no such thing as waste, that all living systems are characterized by a symbiotic relationship with at least one other living system, and that all of life defines itself in a tight and critical interdependency, we cannot help but devise food production systems that mimic the natural world and are totally self-sustaining.
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