New applications for perennial forage species as pasture or rangeland species include introduced cool grasses such as the wheatgrasses (Agropyron spp.) to provide early spring and late fall grazing in traditional warm-season native rangeland areas of the western United States such as the Nebraska Sandhills. In this area, the native warm-season rangeland is not ready to graze until mid-May to early June and goes dormant at the first killing frost which is about the first of Sept. This results in a seven month period where livestock producers maintain beef cattle herds on winter range with supplemental hay feeding (Fig. 3). The use of cool-season grasses six weeks in the spring and six weeks in the fall (Fig. 4) can greatly improve the profitability of ranching operations by reducing the amount of hay feeding and by increasing livestock performance due to the high quality forage produced by the cool-season grasses during the spring and fall (Asay 1995; Bauer et al. 1995). Research to match specific grasses to specific livestock production needs is in progress at several locations in the United States.
The use of pastures by dairy cows was once a common practice in the United States. This practice was largely discontinued by the end of the 1950s. Harvested feeds were economical because of mechanization and cheap energy costs and because the highest milk yields per cow was obtained with specific rations in feeding stations (Elbehri and Ford 1995). Improved fencing and watering systems have reduced pasturage costs and the use of intensive rotational grazing systems have improved milk production and reduced production costs to the extent that the use of pastures in dairy production systems can often improve the profitability of dairy farming (Elbehri and Ford 1995). The trend for increased use of pastures in dairy production systems will likely continue.
The use of pastures to produce broiler chickens is another new use of perennial grasses. Joel Salatin (1993), an innovative farmer in the Shenandoah Valley of Virginia produces broiler chickens by raising newly hatched chicks in brooder houses until they are two to four weeks old and then transfers then to portable mini-pasture pens in a pasture. He has about 100 broilers per pen that are provided water and are fed a growing ration that comprises about 70% of their diet. The remaining 30% of the ration comes from grazing. The broilers are provided a fresh, clean grazing area daily by moving the pens. The broilers that he markets are produced under a type of "free ranging" system that appeals to consumers who want and are willing to pay a premium for a more "natural" product. His system requires intensive management but net return is over $3000/ha. He also markets his technology via his book and videos. Farmers in other areas are using his system to produce chickens on pasture.
Buffalograss has been used on a limited basis as a low maintenance, utility turfgrass for lawns, grounds, and roadsides (Beard 1973). Until recently, common and 'Texoka' were the most frequent types. They produced a light, gray-green turf of low density and variable texture and were not considered highly desirable for most turfgrass uses. Recently, there has been an increasing interest among turfgrass managers for turfgrasses that require less inputs, such as fertilizer, pesticides and labor, and conserve water (Shearman 1994). Buffalograss is a species with a potential to meet these interests. `Prairie' is a turf-type cultivar developed by Milton C. Engelke and released by Texas A&M University that offers improved turfgrass characteristics over 'Texoka' (Riordan et al. 1993).
The United States Golf Association (USGA) is supporting breeding projects that are intended to develop turfgrass cultivars, requiring less inputs and conserving water for golf course roughs, tees, fairways, and greens (Kenna 1994). One project that the USGA has supported since 1984 is a buffalograss breeding project at the University of Nebraska, under the leadership of Terrance P. Riordan with four primary objectives: (1) selecting clones with turf-type characteristics and breeding of cultivars to be planted vegetatively or by seed; (2) determining the range of adaptation of turf-type buffalograsses; (3) developing propagation techniques that improve vegetative establishment and seedling vigor; and (4) identifying management practices that allow buffalograss cultivars to perform in turfgrass situations. The Nebraska program has developed and released three vegetative cultivars ('609', '315' and '378') that are commercially available and are performing well in home lawns, grounds, and golf course roughs. `Cody' and `Tatanka' are seeded cultivars released from this project in 1994. Seed of these cultivars was commercially available in 1995.
The vegetative cultivar, '609', was released in cooperation with Crenshaw and Doguet and has consistently out performed 'Prairie' in the buffalograss trials. Sales of '609' sod exceeded $1.5 million in 1994 and its performance has been excellent in the National Turfgrass Evaluation Program Buffalograss Cultivar trials (Table 1). Its principal market has been in Texas where its turf quality in comparison to other adapted grasses such as St. Augustine grass (Fig. 5) has created a high demand for adapted buffalograss cultivars. '609' is considered to be a southern-type that is less cold tolerant than '315', '378', 'Cody' or 'Tatanka', but it forms a dense, low-growing, medium-green turf in its areas of adaptation. '315' and '378' are northern-types that green-up earlier in the spring and go dormant earlier in the fall than '609' or 'Prairie' (Riordan et al. 1993).
It is apparent that buffalograss is a promising species for low input, water conserving turfs. As a species, buffalograss is quite variable and offers considerable opportunity for improvement by breeding and selection. Research results indicate that cultivars can be developed with more desirable turf color, quality, and overall performance, when compared to common-type selections and 'Texoka'. With increased concerns over environmental quality and water conservation, buffalograss may offer a means to maintain turfgrass function and quality, while reducing inputs and minimizing negative impacts on the environment (Shearman 1994). Other species of perennial grasses will undoubtably be developed to meet specific turfgrass requirements.
Perennial grasses including native prairie grasses are being included in landscaping plans by innovative gardeners and landscape architects. The native prairie grasses being used in landscaping include big bluestem, little bluestem [Schizachyrium scoparium (Michaux) Nash], switchgrass, and others. In many cases, cultivars developed as pasture or reclamation plantings are being utilized, but at a few locations including the Univ. of Nebraska, selection work is being conducted to developed strains and cultivars specifically for use as ornamentals.
Molecular genetics research has made significant advances in making ethanol production from biomass feasible. Recently, Zhang et al. (1995) reported producing a recombinant bacteria that can anaerobically ferment both xylose and glucose sugars to ethanol at yields exceeding 86% of theoretical yield. Research also is being conducted on procedures to break cellulose and hemicellulose down into simple sugars. Research has reduced the cost of producing ethanol from biomass from $0.95 per liter in 1982 to $0.36/liter in 1992 (Wyman 1992). With improvements in both conversion technology and biomass plant productivity, it is estimated that it may be feasible to produce ethanol at $0.16 per liter by 2010 from herbaceous biomass which would make it equivalent in cost to petroleum fuels at $25/barrel for crude oil (Wyman 1992). In a series of evaluation trials with cooperating state universities and the USDA, the Department of Energy (DOE) has identified switchgrass as the most promising species for development into a herbaceous biomass fuel crop. Its desirable attributes include broad adaptation, high yields, stress tolerance and it is harvestable with conventional hay-making equipment. It can produce high yields on marginal lands that are unsuitable for row crop production due to high erosion potential. DOE, USDA, and cooperating state experiment stations are currently conducting breeding and management research to improve switchgrass as a potential biomass crop.
As part of this research, currently available switchgrass cultivars and experimental strains were evaluated in trials in Nebraska, Iowa, and Indiana for their potential as biomass fuel crops (Hopkins et al. 1995). The research plots were seeded in 1991 and harvested in 1991 and 1992. They were fertilized with 112 kg/ha N per acre. The only other cultural practices were the harvesting operations. The highest yielding strains produced over 14 Mg/ha dry matter per acre (Table 2). Turhollow (1994) estimated that switchgrass would have to sell for $43/Mg to $60/Mg to be competitive with corn in the midwest. At a price of $55/Mg ($50/ton), which is a typical price for grass hay in many years, the gross return per ha would be over $770 (Table 2). Assuming 75% conversion of the constituent cellulose and hemicellulose to ethanol, these yields would result in ethanol production of over 4600 l/ha (Table 2).
Average maize yields for the counties in which the switchgrass trials were located ranged from 4760 to 10100 kg/ha (Table 3). In the Midwest, 1991 was a drier year than average while in 1992, the growing season was cooler than average. The average gross return per ha for maize for the three counties averaged $605 to $741 (Table 3). Assuming a conversion rate of 1 liter of ethanol per 2.3 kg of maize, the average ethanol yield from maize from these three Corn Belt counties would have been 3100 to 3800 liters per ha (Table 3). Ethanol feedstocks cost expressed in terms of $/liter would likely be cheaper for ethanol produced from switchgrass (Tables 2 and 3).
Herbaceous biomass fuel plants such as switchgrass would have to be grown east of 100deg. W longitude because of precipitation requirements for economic yields. In this region, which is east of a north to south line 320 km west of Omaha, NE, there are 8 to 16 million ha of land that could be converted to biomass crop production without significant displacement of crops (Graham 1994).
Use of marginal lands for biomass fuel production would produce onsite and offsite benefits similar to the Conservation Reserve Program. If the biomass can be converted to liquid fuels as economically as predicted and adequate yields can be obtained, this conversion of land to energy production could be achieved without the need for massive federal subsidies. Land use for biomass fuel production would be reverting land to its prior use at the early part of this century when the nation was powered by herbaceous biomass via over 25 million head of horses and mules on farms and over 2 head million in cities (Census of Agriculture 1900, 1920). It would also revert to energy production some of the 80 million acres of land that was switched from feed production for horses. The decrease in the numbers of draft animals released approximately 80 million acres of land for other purposes (Census of Agriculture 1954).
Perennial grasses can be high producers of lignocellulosic compounds. These compounds are utilized in industry for paper productions and the production of products such as fiberboard. Currently wood products provide the raw materials for these products. It is feasible that mature perennial grasses could be used in the future as a commercial source of lignocellulosic compounds.
|Turfgrass quality ratings, 1 to 9 ideal basis|
|609 (NE 84-609)||5.0||4.7||4.6||4.6||4.9||6.0||6.1||5.6||6.1||5.4||5.8||5.1||5.6|
|315 (NE 84-315)||5.2||4.7||4.7||4.8||5.9||6.4||5.7||5.5||5.5||4.7||4.2||3.4||5.5|
|Top Gun (BAM 101)||5.0||4.7||4.3||5.4||4.6||5.6||5.5||5.0||5.1||4.6||4.9||3.3||5.0|
|Plains (BAM 202)||4.8||4.3||4.7||4.8||4.4||5.5||5.4||4.8||5.1||4.8||5.2||3.8||5.0|
|Location||Cut 1 (mg/ha)||Cut 2 (mg/ha)||Total (mg/ha)||Gross returny ($/ha)||Ethanolx (l/ha)|
|West Lafayette, Indiana||13.7||2.0||15.7||864||5170|
|Yield kg/haz||Corn pricey ($/kg)|
|Location||1991||1992||1991||1992||Gross return ($/ha)||Ethanol yieldx (l/ha)|
|Saunders County, (Mead), NE||6459||8340||92.03||80.62||635||3217|
|Story County, (Ames), IA||7713||10159||90.46||76.69||741||3885|
|Tippecanoe County, (W. Lafayette), IN||4766||9532||96.36||78.66||605||3108|
|Fig. 1. Typical cattle production system in Corn Belt States.||Fig. 2. Integrated cattle production system in Corn Belt States.|
|Fig. 3. Typical rangeland cattle production system in the Central Great Plains.||Fig. 4. Integrated cattle production system in the Central Great Plains.|
|Fig. 5. A buffalograss turf (right side) growing next to an St. Augustine turf (left) in Dallas, Texas. Note the finer leaf texture of the buffalograss turf.||Fig. 6. Sediment trapped at the base of switchgrass plants growing in a living terrace. Photograph courtesy of Dr. John Gilley, USDA-ARS, Lincoln, Nebraska.|