Initiative to Develop Alfalfa as a Feed Stock for Bioenergy and Bioproducts Production

Transcription

1 Initiative to Develop Alfalfa as a Feed Stock for Bioenergy and Bioproducts Production I. Why the Need for Bioenergy? In his State of the Union Address on January 31, 2006, President Bush stated: Keeping America competitive requires affordable energy. And here we have a serious problem: America is addicted to oil. Indeed, the U.S. consumes more oil than any other country about 20.7 million barrels a day (compared to No. 2 China at 6.9 million barrels per day) 4. And the cost of that oil has gone up 230 percent in the last 10 years (inflation adjusted to 2005) 1. Furthermore, about 60 percent of this crude oil is imported, 1 greatly disrupting the country s balance of trade; petroleum imports account for 19 percent 5 of America s current trade deficit which has been in a negative balance every year since 1976 and is currently more than -$700 billion 6. This dependency on foreign oil also raises huge security issues for the country. Corn-based ethanol is leading the way in biofuel production. There are currently 106 biorefineries in the U.S. producing 5,081 million gallons per year, with another 40 being built and eight being expanded which will bring total capacity to 8,737 million gallons per year 7 ; 20 percent of corn grown in the U.S. is now used for ethanol production. 8 But grain-based ethanol alone cannot meet the government s goal of replacing 30 percent of gasoline usage by 2030 (DOE/USDA-Biomass Report 2005). Currently ethanol replaces only about 3.6 percent of gasoline used in the United States [based on million barrels motor gasoline supplied per day 1 versus 5,081 million gallons ethanol produced per year 4 (42 gallons per barrel)]. Lignocellulosic crop residues (e.g., alfalfa stems, corn stover, wheat straw) and dedicated lignocellulosic biomass crops will play a major role in providing the biomass needs for capturing this level of energy. Alfalfa can and should be one of those dedicated lignocellulosic biomass crops with potential for new co-products for reasons listed below. II. Why Should Alfalfa be Considered for Bioenergy and Bioproduct Production? Alfalfa can be grown in almost every part of the country. In the United States, alfalfa is currently the third most widely grown crop with more than 23 million acres harvested in The technology for cultivation, harvesting, and storing alfalfa is well established, machinery for harvesting alfalfa is widely available, and farmers are familiar 4 Energy Information Administration, U.S. Dept. of Energy 5 FT900: U.S. International Trade in Goods and Services, Sept. 2006, U.S. Census Bureau 6 U.S. Census Bureau, Foreign Trade Division 7 Renewable Fuels Association 8 USDA, Office of the Chief Economist

2 2 with alfalfa production. There is a well-developed industry for alfalfa cultivar development and seed production, processing, and distribution. Although alfalfa cannot provide the entire one billion ton biomass goal for ethanol production articulated by USDOE and USDA, clearly the production capability exists for alfalfa to make a significant contribution to this goal. Alfalfa is a perennial plant that is typically harvested for four years before plowing down for rotation to another crop such as corn. Importantly, alfalfa does not require nitrogen fertilizer, which is a major and increasing cost in corn production. Alfalfa roots engage in a symbiotic relationship with the soil bacterium Sinorhizobium meliloti that fixes nitrogen gas into ammonia, which is assimilated by the plant. Because alfalfa does not require nitrogen fertilizer, energy costs associated with production of alfalfa are low. A recent study showed that energy inputs for production of alfalfa are far lower than for production of corn and soybeans, and slightly lower than switchgrass. In addition, when an alfalfa field is plowed down, some of the nitrogen that was fixed by alfalfa remains in the soil and can provide most, if not all, the nitrogen needed for corn production in the following year. Recent work has also shown that a 4 ton/acre alfalfa hay crop contained the same amount of gross energy as 150 bushels/acre of corn grain but 33% more net energy because of lower fertilizer N use. Utilization of alfalfa as a biomass crop has numerous environmental advantages. There is an urgent need to increase the use of perennials in agricultural systems to decrease erosion and water contamination. Annual row crop production is a major source of sediment, nutrient (nitrogen and phosphorus), and pesticide contamination of surface and ground water. Perennial crops such as alfalfa can reduce nitrate concentrations in soil and drainage water and prevent soil erosion. Alfalfa cultivation also: increases soil fertility through nitrogen fixation; improves soil quality; increases soil organic matter; and promotes water penetration into soil. Corn stover has been proposed as a major source of cellulosic ethanol production; however, continual removal of only 50% of this crop residue quickly results in reduced soil organic matter and declining corn grain yields. Incorporation of alfalfa into rotations with corn production may allow more corn stover removal because of the addition of organic matter to the soil by alfalfa. Alfalfa leaves and stems can be easily separated. The stem fraction is high in cellulose, the substrate needed for ethanol production. The leaves of alfalfa constitute approximately 45% of the total harvested crop and can be used as a valuable co-product. The leaf fraction contains 26 to 30% protein. In its raw state, alfalfa leaf meal can be used as a supplemental protein feed for livestock. Based simply on its protein concentration, alfalfa leaf meal is estimated to have a value of $125 per ton. Wet fractionation of alfalfa has been developed for extraction of higher value protein fractions for animal feed and even human consumption, and can be used to extract numerous natural compounds with possible health-promoting activities. Alfalfa is a rich source of flavonoid antioxidants and phytoestrogens, including luteolin, coumestrol, and apigenin, which have been identified as potential nutriceutical products. In addition, genetic engineering of alfalfa is well established, enabling development of novel proteins and other co-products.

3 3 III. Research Initiative A. Understanding and developing the genetic and molecular changes needed to make alfalfa an efficient feed stock for bioenergy and bioproducts. For alfalfa to be a competitive biofuel feedstock, research is needed to develop alfalfa germplasm that yields more biomass (both leaf and stem) with reduced production costs. Breeding and/or molecular modification for enhanced yield of potential value-added coproducts will also be important. Cost-effective biomass processing and fermentation to ethanol are needed to make cellulosic-derived ethanol commercially viable. A major limitation to use any biomass for ethanol production is the difficulty and expense of breaking the biomass down into sugars that can be fermented into ethanol. Lignin is a cell wall component in all land plants that interferes with enzymatic degradation of cellulose and can severely limit the conversion of biomass to ethanol. Research is needed to develop alfalfa germplasm with increased or modified cellulose, cell wall degrading enzymes within alfalfa vacuoles or plastids, and reduced concentrations of lignin in order to limit expensive pre-treatment processes for ethanol production. 1. Increase yield: Historically, alfalfa has been produced as a livestock feed. Genetic research and management strategies have focused on maximizing the leaf protein and minimizing stem portions of the plant to produce high quality forage products to be consumed by ruminant livestock. In an alfalfa biomass/biofuel production system, both leaf and stem yield will need to be maximized. Biomass alfalfa germplasms will likely be managed differently and traits specific to increased stem yield such as delayed flowering, reduced leaf senescence, and non-lodging stems will need to be incorporated. Increased knowledge of alfalfa plant development and the identification of key developmental genes will aid in the development of high biomass yielding plants and improving yields under shorter (2-3 yr) rotations for improved compatibility with alfalfa-corn biomass rotations. 2. Determine factors that enhance conversion efficiency: Ethanol production from yeast currently is restricted to efficient utilization of glucose with perhaps limited use of other hexoses, but no utilization of pentoses or uronosyls. Alfalfa germplasm typically ranges from 20 to 35% glucose (primarily as cellulose) on a dry matter basis. Increasing the cellulose content coupled with less lignin would lead to more efficient and economical bioenergy production. There appears to be genetic variation for cellulose content that could be exploited through proper selection programs. Increased knowledge of sugar metabolic pathways and identification of key genes (e.g., ellulose synthase, sucrose synthase, glucose dehydrogenase, etc.) would provide powerful tools to alter structural carbohydrate formation in alfalfa designed specifically for bioenergy. Low lignin alfalfa is also under development using biotechnology by industry laboratories. Additional basic research is needed to understand the complete lignification process and how to control it within specific cell wall types. Increased cellulose and decreased lignin in specific cell types will provide more robust plants with higher energy conversion efficiencies.

4 4 3. Determine factors that enhance value of co-products: Alfalfa contains large amounts of protein which, in addition to being a high value feed product, could serve as a starting material for development of commercial applications for proteins such as coatings, fibers, emulsifiers, etc. Transgenic alfalfa may also be a good candidate for production of industrial proteins. The question is not so much how to produce more protein from alfalfa, but how to isolate it and use it most effectively (See section C below). Leaf meal has high protein content along with carbohydrates that are relatively easily digested by ruminants. Alfalfa is also rich in phytochemicals (e.g. phytosterols). Genetic research needs to be conducted to evaluate and improve the quality of alfalfa protein and leaf composition for feed and non-feed (industrial) uses. Genetic control for most, if not all, of these potential co-products is unknown. Increased knowledge is required to understand the metabolic synthesis of secondary products in alfalfa and to test the feasibility for producing unique products that would have consumer appeal and support, such as industrial enzymes or products possessing nutricuetical value (e.g. lutein, carotenoids). A challenge to utilizing protein in alfalfa (whether for feed or non-feed use) is to limit in situ proteolysis to avoid diminished quality. There is work currently underway to develop a polyphenol oxidase (PPO) based system that would inhibit proteolytic activity in harvested alfalfa. Additional work is required to develop a complete system (polyphenol oxidase plus o-diphenol substrates). It may be possible to use the PPO-o-diphenol system to inhibit proteolysis as well as cross-link proteins that would improve their utilization not only as animal feed, but potentially as starting materials for non-feed uses. 4. Improve alfalfa response to environmental stress: Alfalfa is widely adapted to grow in almost every region of the United States. It is currently grown on more than 23 million acres, making it the third most widely grown crop in the U.S. However, yields are dependent upon adequate water supplies to maximize the genetic growth potential. There is a need to increase our basic knowledge of metabolic changes that occur when alfalfa is placed under water stress. Soluble carbohydrates (non-reducing, polyalcohols) are frequently found to decrease the severity of responses to water stress. Identification of genes involved in these pathways, and their level of expression or lack of expression in alfalfa, would provide a foundation upon which biochemical strategies can be developed that would lead to plants with improved water use efficiencies. Transgenes for improved drought tolearance/water use efficiency are needed and currently under development by various biotech companies. Several of these are now being expressed in alfalfa by industry breeders. Basic research in additional gene discovery and testing of current gene candidates offer promise for the development of alfalfa plants with improved water use efficiencies. Additional positions needed to adequately enhance research efforts in Section A: 3 scientists (plant physiologist, biochemist, molecular geneticist, and/or molecular biologist)

5 B. Developing management systems for producing alfalfa as a feed stock for bioenergy and bioproducts. 5 Adding two or three years of alfalfa production to a corn-soybean or continuous corn rotation could increase biomass yields while reducing nitrogen fertilizer and pesticide costs for corn by up to 50%. To maximize biofuel production from biomass at reasonable cost, alfalfa must be brought rapidly to full production, harvested at appropriate intervals, and grown in optimized rotations and production systems with corn and soybeans. Although management systems for producing alfalfa and row crops for feeding livestock are well established, the following research must be conducted to develop high-yielding and low-cost systems for producing biofuels and co-products from alfalfa and row crops. 1. Develop methods for establishing biomass-type alfalfas with corn and soybeans to rapidly bring alfalfa into full production at minimal cost. 2. Refine the cutting management of biomass-type alfalfas to optimize the yield versus cost of producing ethanol from alfalfa stems. 3. Develop appropriate crop rotations and production systems for alfalfa and row crops for various regions in the United States; take into account economic analyses (optimize the yield verses cost of producing biofuels from alfalfa, corn, and soybeans) as well as environmental considerations (minimizing soil loss, nutrient loss, and loss of wildlife habitat). 4. Examine the amount, value, and rate of availability of legume and carbon credits from alfalfa over time. Additional positions needed to adequately enhance research efforts in Section B: 2 scientists (agronomist, soil scientists, and/or soil microbiologist) C. Understanding and developing harvesting, storage, and transportation systems needed to produce alfalfa as a feed stock for bioenergy and bioproducts. In order to utilize a biomass crop or crop residue as a feedstock for bioenergy, we must meet the challenge of developing cost effective harvesting, storage and transport systems that minimize energy inputs and maximize energy conversion efficiencies. Many questions need to be answered, including: How does ensiling affect use as a biofuel feedstock?; How does dry matter loss during ensiling change protein availability?; How compatible is a biomass use with a haylage harvest system?; What are the energy requirements for production, transport, and processing? 1. Improved harvesting strategies. It is unlikely that a single type of harvesting technique will be applicable to alfalfa biomass that will capture all of the potential benefits from this crop. Research is needed to explore the range of mechanical harvesting techniques that will result in low inputs and aid in the separation of the total plant into high-value/low-value production streams. This may include evaluating systems that would remove leaves (high-value) from stems (lowvalue) as the crop is standing in the field. Other options may include in-field harvesting/processing to remove the soluble fraction (protein, value-added products, etc.) while leaving the fiber fraction for fermentation to ethanol. For certain scenarios it may be necessary to re-evaluate the macerator technology where the overriding factor is rapid

6 6 drying to get the crop off the field as quickly as possible followed by dry fractionation of leaves and stems. 2. Processing/storage options. For every type of biomass used for bioenergy, there is a need for pretreatment to enhance the availability of fermentable sugars. Research is needed to develop processing and storage options that decrease or eliminate the amount of pretreatment necessary at the fermentation facility. One of the challenges of biomass to bioenergy enterprises is having adequate storage of materials that minimizes the losses yet is capable of dealing with issues such as bulk density and transport. Research is needed to explore processing techniques that remove the soluble fraction (protein, etc.), leaving an enriched fiber fraction that is further processed and stored as silage. During the ensiling process, to preserve the material, pretreatments could be applied that would enhance the fermentation value of the material coming out of storage. Work is needed to determine the type and level of enzymes that would be most effective as biological treatments. Likewise, information is needed as to what chemical treatments could be applied to render more of the fiber available for fermentation. Evaluation would be needed to determine the economic feasibility of on-farm processing that would offset increased shipping costs. 3. Reduced transportation costs. One of the limitations of biomass use is the cost of transporting to a central fermentation facility. The bulky nature of most biomass results in high transport costs that quickly offset the value gained from energy output after fermentation. Research is needed to explore densification techniques, such as double compression or cubers, to minimize shipping costs. This would have to be coupled with the processing work described above to maximize value of all products that can be gleaned from the total biomass. Processing (wet grinding, expression) and densification (compaction, reclaim juice) may be coupled with other technologies that would be applied at the time of densification rendering the pellets easily disassociated upon arrival at the fermentation facility (i.e., application of a water soluble binder). Other possibilities may include ensiling into transport tanks that would be shipped intact to the fermentation site. Additional positions needed to adequately enhance research efforts in Section C: 2 scientists (plant physiologist, biochemist, molecular geneticist, molecular biologist, and agricultural engineer.) D. Process-related barriers to converting alfalfa fiber to ethanol and suggestions for overcoming them. Use of alfalfa stems as a feedstock for ethanol production has potential net energy value (on a tonnage basis) greater than other herbaceous energy crops being considered including switchgrass and reed canary grass. However, little research has focused on developing key technologies for unlocking its fiber for ethanol and butanol production. To date, the vast majority of studies have concentrated hardwood, softwood, and C4 grasses in the last 10 years we are only familiar with 3 papers published that have significant findings for converting legume biomass to ethanol. The development of conversion technologies for alfalfa will serve as a model for converting other leguminous species as well. Research into various methods of conversion need to be explored to determine most effective, cost-efficient method of production, e.g., gasification, cellulosic.

7 7 Converting biomass to ethanol involves the following process steps: 1) pretreating the biomass to open up the plant structure; 2) enzymatic digestion to convert cellulose and (as necessary) xylan to sugars; 3) fermentation of these sugars to produce ethanol or butanol. Alfalfa represents a unique combination of properties compared to other sources of biomass, including: 1) significant soluble sugars (e.g. sucrose); 2) pectin; 3) highly differentiated plant cell wall structure, especially as related to distribution of lignin; 4) possibility for co-products. The absence of proven conversion technology adapted for alfalfa that allows for optimal production of ethanol and co-products is a barrier to alfalfa developing as an energy crop. 1. Pretreatment: The effectiveness of a pretreatment is measured by sugar or (if fermented) ethanol produced from the pretreated biomass when using a minimum loading of enzymes. Treating biomass with dilute sulfuric acid at high temperatures ( ºC) is by far the most common pretreatment for biomass; it is highly effective for converting hemicellulose directly to fermentable sugars and greatly increases the digestibility of cellulose for subsequent enzyme conversion to glucose. However, dilute acid as practiced on woody biomass or corn stover would be ineffective on alfalfa because of its soluble sugar content. These soluble sugars are converted to furans by this treatment, which inhibit the subsequent ethanol fermentation. Alfalfa also has a higher buffering capacity to acid than other sources of biomass and, therefore, more acid would be needed to effect its conversion. Only two papers report on using alternative pretreatments. In order to commercialize alfalfa-based ethanol, it would be highly beneficial to evaluate the plant biomass with a variety of pretreatments to identify the effective ones. Also, as capital costs associated with pretreatment remain an important barrier, this work will allow for the evaluating of pretreatments with potentially lower equipment costs than dilute acid pretreatment. Available Pretreatments for Alfalfa Alkaline peroxide, ammonia fiber explosion (AFEX), liquid hot-water, ozonolysis, organosolvent, room temperature liquid ionic solutions 2. Enzymatic hydrolysis: Commercial enzymes marketed for biomass conversion have been extensively applied to C4 grasses and woody biomass and largely to dilute-acid pretreated material. It is envisioned that digesting alfalfa will require the blending of new enzymes for effective conversion of biomass to sugars. For example, pectinases are usually not blended with cellulases because most other sources of biomass evaulated as feedstocks do not contain appreciable amounts of pectin. Furthermore, the little data available for legumes suggests that they require more severe pretreatment conditions than C4 grasses; higher severity conditions raise capital costs and lead to more inhibitors. It is possible that developing specific enzyme blends for alfalfa may help compensate for this difference. Finally, there are no commercial enzyme blends produced for converting pretreated xylan into fermentable sugars and therefore new custom blends will be needed for this purpose. 3. Fermentation: As for all biomass to ethanol fermentations, an efficient biocatalyst capable of converting all the sugars present (pentoses as well as hexoses) to ethanol remains a challenge requiring further research and development. Research into adjuvants, which could potentially enhance EtOH yield, should be explored as well. In addition, alfalfa contains significant amounts of pectin carbohydrates. Only limited studies exist on converting pectin into ethanol. Therefore, microorganisms will need to be evaluated and possibly genetically modified to use pectin released sugars. Also, if

8 specific enzymes greatly increase digestion of pretreated alfalfa, the fermentative microorganisms can be engineered to directly produce the enzymes, thereby, possibly lowering overall process costs Recovering valuable co-products. The economic viability of any bioconversion process can be tremendously impacted by the generation of valuable coproducts in addition to the primary product in this case, fuel ethanol. Alfalfa contains large amounts of protein which, in addition to being a high value feed product, could serve as a starting material for development of commercial applications for proteins such as coatings, fibers, emulsifiers, etc. Research needs to be conducted to evaluate alfalfa protein for these non-feed uses. In addition, legumes such as alfalfa are rich sources of phytochemicals (e.g. phytosterols). The potential for isolating these very high value products should also be explored. 5. Co-processing: A mature fiber-based energy economy may include a mixture of legume and C4 grasses. Using current technology, processing both materials at the same facility would be cost prohibitive. However, if improved pretreatments and enzymes are discovered for use on legumes, it is quite possible these may allow for co-processing of legumes with C4 grasses. To give a direct example, if more effective enzyme blends allow for legumes to be pretreated under similar severity as C4 grasses, both fibers might be pretreated in the same reactor. There are no published papers that demonstrate simultaneous pretreatment of fiber from multiple sources and as such this represents a barrier not only to the use of legumes but to the development of the whole industry. Additional positions needed to adequately enhance research efforts in Section D: 4 scientists (carbohydrate chemist, microbiologist, chemical engineer, processing engineer, biochemist, and/or enzymologist and/or polymer chemist) E. Whole-system analysis to determine advantages and impacts of using alfalfa as a feedstock for bioenergy and bioproducts. main author Peter Vadas Current ethanol production in the U.S. almost exclusively uses corn grain as a feed stock. However, future ethanol production will likely use cellulosic biomass derived from agriculture crop as feedstocks. Two of the most commonly mentioned cellulosic feedstocks are switchgrass and corn stover. However, alfalfa has a number of characteristics that make it a strong candidate as a cellulosic feedstock. A systems analysis to demonstrate these characterstics (see table 1), especially compared to switchgrass and corn. 1. Energy and economic analysis: We estimated production costs and energy balances for three likely cropping scenarios that would be used to produce ethanol. These include: 1) continuous corn; 2) continuous switchgrass; and 3) an alfalfa-corn rotation. Energy balances consider inputs required to produce the crops and the energy represented in potential ethanol and animal feed byproducts produced. For corn, both grain and stover would be used to produce ethanol, and distillers grains would be animal feed by-products. For alfalfa, stems and leaves would be separated, with stems used for ethanol and leaves used to produce animal feed. We simulated both normal and high crop yield scenarios.

9 9 Table 1. Production costs and energy balances for likely biofuel crop rotations. Rotation 3 years alfalfa 1 year corn 3 years alfalfa 1 year corn continuous switchgrass continuous switchgrass continuous corn continuous corn Yields 2 a or 4 b ton/acre alfalfa 158 bu/acre corn grain 4.4 ton/acre corn stover 3 a or 6 b ton/acre alfalfa 158 bu/acre corn grain 4.4 ton/acre corn stover Total Costs ($/acre) Net Energy Produced (GJ*) Net Energy Cost (cents/gj*) Net energy of Ethanol (MJ**/gallon) , , , ton/acre , ton/acre , bu/acre grain 2.3 ton/acre stover 189 bu/acre grain 3.1 ton/acre stover 1, , , , * giga joules **mega joules (joule is the International System unit of energy) a new seeding b established stand Net energy produced is greatest for corn and least for switchgrass, with the alfalfacorn rotation in between the two. Total alfalfa-corn production costs are less than continuous corn costs but greater than continuous switchgrass costs. With these production cost and energy balance characteristics combined, net energy production costs are least for corn and greatest for switchgrass, with the alfalfa-corn rotation in between the two. However, the alfalfa-corn rotation yields the greatest amount of net energy in potential ethanol and animal feed by-products per gallon of ethanol produced. Thus, the alfalfa-corn rotation has the greatest efficiency of energy production.

10 10 The greater energy efficiency of the alfalfa-corn rotation is primarily because alfalfa requires no nitrogen fertilizer. Unlike corn and switchgrass, alfalfa converts atmospheric nitrogen to useable nitrogen for growth. Furthermore, alfalfa can leave enough available nitrogen in the soil to supply most of the nitrogen needs of the succeeding corn crop. For example, corn may normally require 150 to 200 lbs of nitrogen fertilizer per acre. When planted where alfalfa was grown the year before, corn needs only a maximum of 30 lbs of nitrogen fertilizer. Because alfalfa requires neither nitrogen fertilizer, which is becoming more expensive as energy prices increase, nor annual tillage and planting, an alfalfa-corn rotation is cheaper to produce than continuous corn, but not quite as cheap as switchgrass. Continuous corn generates the greatest volume of ethanol, but its high energy input reduces its net energy efficiency. Switchgrass has low input energy and cost requirements, but yields the least volume of ethanol. Overall, lesser input energy and cost requirements than continuous corn and greater ethanol yields than switchgrass make an alfalfa-corn rotation the most energy efficient. Furthermore, the USDA-Agricultural Research Service is currently developing new varieties of alfalfa that can produce 42% more biomass yield and allow less frequent harvesting during the year, which can decrease costs of production and increase ethanol yield, thus making alfalfa even more energy efficient. 2. Impacts on Livestock Industry: When used as a cellulosic ethanol feedstock, alfalfa will likely be separated into cellulose-rich stems for ethanol and protein-rich leaf meal for livestock feed. This is similar to corn-based ethanol, where both ethanol and distillers grains for feed are produced. Switchgrass does not have enough protein to produce a feed byproduct. Widespread incorporation of alfalfa leaf meal into the livestock feed industry could occur very quickly as a substitute for soybean meal or alfalfa hay. Recent corn prices greater than $3 per bushel concern the livestock industry that greater demand for corn grain for ethanol will decrease corn feed supply and increase its price. Producing alfalfa for ethanol is unlikely to have a similar result on feed supply and price because alfalfa hay for feed commands a greater price than the ethanol industry can pay. Rather, alfalfa for ethanol could result in new acres of alfalfa planted and harvested, with alfalfa leaf meal an additional livestock feedstuff on the market. While distillers grains from corn ethanol production is a valuable feedstuff, their use is limited because distillers grains have the same amino acid profile as corn grain, which requires other protein feeds be fed to meet amino acid needs. Conversely, the amino acid profile of soybean or alfalfa leaf meals should complement corn. Because protein production per acre from alfalfa leaf meal is greater than corn distillers grains and equal to soybean meal, diversion of acres from corn

11 11 or soybeans to alfalfa would not decrease the livestock industry s protein feed supplies. The opposite is true for switchgrass because it provides no protein feeds. 3. Environmental Services: Alfalfa offers a number of environmental benefits relative to corn or switchgrass. First, alfalfa requires no nitrogen fertilizer, and its very deep roots can absorb water and nutrients from as deep as 15 feet. This enables alfalfa to reduce contamination of groundwater drinking supplies by leaching of nitrogen fertilizers. Second, alfalfa is a perennial crop that provides excellent soil cover and develops deep, extensive roots. These characteristics reduce soil erosion, which maintains soil quality and productivity and reduces surface water pollution. Third, alfalfa s ability to increase soil nitrogen increases soil fertility and biomass production, which in turn increases storage of atmospheric carbon in the soil. Increased soil carbon sequestration can help reduce the impacts of global warming. Fourth, alfalfa has genetic resistance to many pests and may require less pesticides compared with other crops, which decreases the impact of crop production on the environment. Fifth, there is evidence that organisms around alfalfa roots can efficiently degrade petroleum products and carcinogenic hydrocarbons in contaminated soils. Alfalfa may be able to mitigate soil and water contamination by heavy metals, Chromium 6, perchlorate, and atrazine. Finally, alfalfa improves wildlife habitat due to its nesting cover, abundant insects, perennial growth pattern, and feeding opportunities. Researchers from California have identified over 1,000 species of insects, spiders, mites, and other relatives that inhabit alfalfa fields. Additional positions needed to adequately enhance research efforts in Section E: 3 scientists