What should Biofuel agriculture look like?

Foresight will be required to prevent biofuel agriculture from creating problems as serious as the issue it tries to resolve. It is said that every problem started its life as a solution. Our huge requirements for energy started life as a solutions; transportation, creation of tools, increased agricultural productivity. Thus, biofuel agriculture can create problems larger than the problem it is envisioned to resolve. Competition with food resources, destruction of forests, depletion of the soil, destruction of aquifers, and economic disequilibrium may occur.

Following are a list of criteria for successful long term biofuel production.

Local adaptation: Plants should be selected for the environment where they are to be grown. For dry lands appropriate plants should be selected. Trees may be more appropriate for hilly or dry areas. Wind breaks can be made with biomass tree species, which can help protect the soil and provide shade and habitat.

Perennials: Perennial plants which re-grow from their roots after harvest are advantageous. This avoids damage to the soil, and can actually enrich the soil and take more carbon dioxide out of the air. It saves on cost. Grasses such as switchgrass and miscanthus can be repeatedly harvested. Some fast growing trees may be cut and allowed to regrow either as coppices or as single stem trees. Examples include poplar, willow, alder, and certain acacia trees.

Low irrigation requirements: The large aquifers of our country are being depleted by agriculture. Water shortages have been predicted to be more damaging to our civilization than fuel shortages. It would be a mistake to deplete our reservoir of fresh water to supply fuels. Biofuelstock plants should ideally be adapted to the rainfall patterns of environment were they are grown other than irrigation to get the plants established. In dryland farming use of perennial crops and non-till methods are especially important for retaining moisture in the soil.

Low pesticide requirements: Some plants are more resistant to disease and to insect attack. Biomass plants are less susceptible than seed crops. Disease resistance may be bread into plants, and this is more safely done in biomass plants than in food crops where the resistance to insects may be because of alteration in flavor or toxins in the plant. Native plants are usually more resistant to the insect and diseases found in the native environment. Polyculture usually lowers the requirements for insecticides.

Polyculture: Polyculture is the agricultural practice of using multiple crops in the same space. This is what is found in natural environments. Crop diversity decreases the susceptibility monoculture has to diseases. Even planting several genetically diverse varieties of the same species can have a large benefit. In a study by Youyong Zhu et al, planting a mix of rice varieties was found to give a yield of 89 percent greater than that with single varieties, and that after 2 years use of fungicides could be eliminated when a mix of varieties were. In a study in Minnesota of native grasses a mix of species gave a greater biomass yield than any single species grown in monoculture. When genetically similar plants of a single species are grown together in large areas the risk of destructive insects and for plant diseases is high. Disease can easily spread and find ready hosts, since all the plants are closely related. Insects can resist pesticide if frequently used, and a large enough population of them is present. Agricultural Research Service plant geneticist Michael Casler has spent the over 10 years breeding switchgrass. He believes that this plant’s biofuel future lies in specially designed seed mixtures with beneficial legumes that fix their own nitrogen such as native pure prairie clover and Illinois bundleflower

Polyculture would be difficult for food crops, as different harvest times, and harvesting techniques would be required, and separating the crops would be difficult. This much less of an issue for biomass production. Even if oilseed plants were mixes with cellulose mass plants, separation of seeds or of the oils from the cellulose would not be a technical and may not be an economic problem.

Low fertilizer requirements: With corn a large amount of the fossil fuel investment is the natural gas used to make fertilizer. Pesticides and insecticides are also made from fossil fuel feed stock. Corn yield increases dramatically with high levels of fertilizer, and this is required for it to be economic. Not all crops require this level of agricultural intensity. Many legumes have root nodules which are able to fix nitrogen from the air, and thus add nitrogen to the soil. Other plants increase the availability of phosphorus in the soil. Perennial plants often had lower fertilization requirements. Polyculture, where more than one plant is grown together may reduce need for fertilizers. Cover crops in the brassica family, such as oilseed (canola) which may be used for biodeisel are deep rooted plants that can help open subsoil hardpan (Schonbeck & Morse 2006). It has been recommended that Vetches, a leguminous plant, perform well over a wide range of soils be planted along with brassica to suppress weed growth. Vetch can fix over 100 pounds of nitrogen per acre and release about half of it to the following cash crop. They also make soil phosphorus more available and provide habitats for beneficial insects.

Low Lignin biomass plants: Lignin in plant growth decreases the ability of current alcohol producing technology to extract energy from plants. Lignin is made up of 5 carbon sugars rather than 6 carbon sugars as cellulose is. Technologies are being developed for utilizing lignin as biofuels stock, but these may have added costs. Paper production also prefers low lignin sources. Low lignin varieties of fast growing trees can be used for biofuels. There are hybrid poplar, aspen, willows, and eucalyptus varieties low in lignin. Low lignin sorghum has also been developed.

Biomass rather than seed crop: With corn it is starch in the seeds which are used to make grain alcohol. The plant itself is usually not used. In Brazil where the alcohol is made from sugar cane the stem of the grass is crushed for the sugary juices in the stem, and the crushed stem is used as fuel for drying the sugar and for generation of electricity as a byproduct. Higher yields can come when the biomass of the plants are used. Even if the crop is an oil producing plant, the rest of the biomass may be harvested for its cellulose content.

High efficiency growth and carbon fixation: C4 photosynthetic plants, such as many grasses, have a more efficient photosynthetic pathway than C3 plants. C4 pants include corn, sorghum, sugar cane and switchgrass. C4 plants have an advantage of better adaptation to heat and drought conditions compared to C3 plants. This does not limit biomass production to C4 plants. A hybrid Larch tree has been developed which can fix 30% more carbon than typical larch trees. High carbon fixing varieties of switchgrass sorghum and eucalyptus have been selected. Cassava has one of the highest rates of CO2 fixation and sucrose synthesis for any C3 plant. Researchers from Ohio State University have recently developed a transgenic cassava with starch yields up 2.6 times higher than normal plants

Low Processing Energy: Corn ethanol has a high processing cost. Seed oils have a much lower cost, as the oil is easily separated and do not require distillation. Ethanol has a high processing cost as separating the alcohol from water is energy intensive. Other biofuels have lower processing costs.

Low transportation cost: Biomass conversion should be decentralized and local for low density products. For example, alcohol production should be decentralized so that the fuel stock does not have to travel far, and the alcohol may be used locally. Butanol can be transported by pipeline, and development of pipeline transportable biofuels is desirable. More energy dense biofuels may be transported further, but local conversion is advantageous. Vegetable oils should be processed local when possible to save on transportation costs. Biomass agriculture will be limited to species which can be processed locally.

Good Field Storage: Sweet sorghum has many advantages for biomass production. One disadvantage is that it has poor field storage properties. When it is ready to harvest, it should be done then, or it begins to loose its sugar content. Switchgrass can be allowed to dry in the field, and this may even lower the transportation and processing cost as it looses excess water. Woody biomass such as low lignin poplar may be harvested when the market is ready, and even after cutting have a good shelf life.

Biodiversity: Corn is a monoculture where huge tracts of land are devoted to a single crop. In test done in Minnesota, mixtures of native field plants gave more biomass than single species of grasses and more than intensively grown corn without use of fertilizer or pesticides. This biodiversity supports wildlife and beneficial insects.

Protection of native species: Plants used for biomass promotion should preferably be native species, or species not likely to become invasive. Plants which require spread by rhizomes, or which are not seed bearing are less likely to become invasive. Chinese tallow tree can give enormous biodiesel yield, but can become easily invasive.

Wildlife and migration corridors and habitat: Long cycle biomass or tree crop biomass can be used as habitat and migration habitat for birds and other species, while monoculture of annuls does this poorly.

Protection of wild lands: Wilderness is a desirable asset to our society. Science has much to learn from the remnants of the great wilderness that made up much of America. Palm Oil plantations in Southeast Asia for biodiesel has caused the destruction of large areas of forests. Destruction of our forests and other wild lands must be avoided in the pursuit of bioenergy.

Soil protection and enhancement: Moldboard plowing turns the soil over and helps eliminate weeds and softens the soil for planting. With repeated plowing however, plowing causes the formation of hardpan. The soil becomes impenetrable to roots and restricts growth and yield. Water trapped above the hardpan can drown crops. Plowing decreases organic matter in the soil and thus decreases the carbon sequestration of the soil leading to increased CO2 content in the atmosphere. Plowing breaks up the root structure and cohesion of the soil increasing soil erosion. Plowing compacts the soil decreasing air space and restricts root growth. Hardpan and compaction increase runoff, flooding and depletion of groundwater. Methods with limited or no tillage can protect the soil from erosion.

Some species will break up hardpan soils and some will increase the availability of minerals. Some mesquite species will tolerate high salt content in soils and actually remove salts from the soil. Biomass species can be used to rest and repair soils. This may be done as crop rotation.

Does not replace food production: Biofuels should not compete with food production. If done correctly, biofuel production should complement food agriculture. Some biofuel byproducts may be used as animal feed and replace feed which is currently grown.

Supports Beneficial Insects: Honey bees pollinate one third of all U.S. Crops. We have become dependent on one species, which acts as migrant laborers with hives moving farm to farm. Meanwhile faming practices continue to destroy colonies of native bees because of use of pesticides and plowing which destroys hives of native bees which nest in the earth. Monoculture robs them of a succession of flowering plants throughout the season on which they can forage. Insecticides are fairly indiscriminant and kill beneficial as well as harmful insects. Planting strips of clover between rows of cotton has been shown to increase yield and support songbirds and beneficial insects.

Sustainability: The great hardwood forest of the Ohio Valley were the worlds largest temperate hardwood forest. It took less than 50 years of charcoal making for steel production to destroy these forest. I took tens of millions of years to create the planets petroleum reserves. In a span of less than 50 years over half of the world’s oil reserves have been depleted. In less than 50 years of farming 625,000 square miles of grasslands were turned into the Dust Bowl of the 1930’s which displaces 2.5 million people, teaching us how easily soil and water are depleted. Biomass production should be geared towards improving these limited resources. Agricultural mining will undermine the long term viability of biomass and food production. Fossil aquifers, such as the Ogallala aquifer in the U.S., are not renewable resources should not be used for production of biofuels. In parts of Texas, Oklahoma and Kansas the aquifers have fallen 30 meters. China is quickly depleting its ground water with large aquifers falling as much as 3 to 6 meters a year, and China's fall in grain production of over 20% over the last years has been blamed in part on this. Unsustainable depletion of water resources will only make for another crisis.

Limited Subsidies: Biofuel Agriculture should be left to stand on it own in a level playing field, or else external forces will shape it rather than the economics of it on its own. If solar photovoltaics are economically more efficient, the market should decide on the winner, not politics. Subsidies should only occur to get the process started, with any subsidies limited to assuring that biofuel production is environmentally sustainable, or as seed money to prove the required technologies. Of course subsidies for oil and nuclear also need to be eliminated to attain a level playing field.

© 2007