ORNUSub/85-27412/5&P1

EVALUATION OFPOTENTIAL HERBACEOUS BIOMASS CROPS ON MARGINAL CROPLANDS: 1) AGRONOMIC POTENTIAL
Final Report 1985-1989 J.H.Chemey KD.Johnson J.J. Volenec E.J. Kladivko D.KGreene Department ofAgronomy Purdue University West Lafayette, IN 47907 Date Published- July. 1990

Research supportedby Biofuels Systems Division Office ofTransportation Technologies Activity No. EB 24 01 00 0 Report preparedby Department ofAgronomy Purdue University West Lafayette, Indiana 47907 under Subcontract 19X-27412C for Herbaceous Energy Crops Program

Environmental Sciences Division OAKRIDGE NATIONALLABORATORY Oak Ridge, Tennessee 37831-6285 operated by MARTINMARIETTAENERGYSYSTEMS, INC. for the U.S. DEPARTMENTOFENERGY under contract DE-AC05-840R21400TABLE OF CONTENTS TABLE OFCON1ENTS................................................................................................................. LIST OFFIGURES.......................................................................................................................... LIST OFT ABLES............................................................................................................................. ABSTRACT ........................................................................................................................................ INl'RODUCTION............................................................................................................................ OBJECTIVES...................................................:................................................................................ PROCEDURES................................................................................................................................. Species Selection.......................................................................................................................... Site Selection................................................................................................................................ Crop Management....................................................................................................................... Perennial Crops...................................................................................................................... Doublecropping Sorghum and Winter Rye....................................................................... Interseeding ofSorghum into Perennial Grasses.............................................................. Photoperiod Sensitive and Insensitive Sorghums............................................................. Yield and Persistence ofSouthern U.S. Species ............................................................... Big Bluestem compared to Switchgrass.............................................................................. CompositionalAnalyses ............................................................................................................. Nonstructural Components.................................................................................................. Structural Components......................................................................................................... Soil Analysis............................................................................................................................ RESULTS AND DISCUSSION..................................................................................................... Soils................................................................................................................................................ Objective 1 - Perennial Grass and Legume Production......................................................... Production Potential ofGrasses.......................................................................................... Production Potential ofLegumes........................................................................................ Plant Composition................................................................................................................. Hemicellulosic Sugars and Phenolic Monomers............................................................... Objective 2 - Production ofSorghum Doublecropped with Winter Rye............................ Winter Annual Rye................................................................................................................ Sweet Sorghum and Sorghum-sudangrass.......................................................................... Objective 3 - Production ofSorghum Interseeded into Perennial Grasses ........................ Objective 4 - Production Potential ofPhotoperiod-Sensitive and Insensitive Sorghums Plant Composition................................................................................................................. Objective 

### 5 -Yield and Persistence ofSouthern U.S. Species.............................................. Objective 6 - Relative Productivity ofSwitchgrass and Big Bluestem................................. SUMMARYAND CONCLUSIONS............................................................................................. REFERENCES.................................................................................................................................. iii 

### v vii



### ixV 1 

### 2 3 3 4 

### 5 5 6 6 6 7 7 8 8 8 8 9 9 9 9 14 14 16 16 16 16 

### 20 24 24 27 27 30 32UST OFFIGURES


### 1 Switchgrass yield response to nitrogen fertilization (0, 50, 100, 150, and 200 kg N ha-1). Means offour replicates and one location in 1986, three locations in 1987, and four locations in 1988 and 1989..................................................................... 12 2 Tall fescue yield response to nitrogen fertilization (0, 50, 100, 150, and 200 kg N ha-1). Means offourreplicates and two locations in 1986 and four locations in 1987-89............................................................................................................... 13 3 Reed canarygrass yield response to nitrogen fertilization (0, 50, 100, 150, and 200 kg N 

### ha-1). Means offour replicates and one location in 1986, three locations in 1987, and four locations in 1988 and 1989.................................................... 13 4 

### Switchgrass composition, 1988 ............................................................................................ 17 5 Reed canarygrass composition, Harvest Date 2, 1988...................................................... 17 6 Birdsfoot trefoil composition, Harvest Date2, 1988........................................................ 18 7 Alfalfa composition, Harvest Date 3, 1988 ........................................................................ 18 8 Winter annual rye yield response to nitrogen fertilizer carryover from applications to sorghum in previous years ......................................................................... 9 Sweet sorghum yield response to nitrogen fertilization (0, 50, 100, and 150 kg N ha-1) averaged overfour replicates, four locations, and two tillage 19

treatments............................................................................................................................... 22 10 Sweet sorghum ('M81E') stover composition, 1988......................................................... 26 11 Sorghum ('V2319') stover composition, 1988................................................................... 26



### vLIST OFTABLES

1 Aggregate stability (meanweight diameter, MWD) ofsoil as influenced by location and species............................................................................................................... 10 2 Aggregate stability (mean weight diameter, MWD) ofsoil in doublecrop sorghum plots as influenced by location, nitrogen fertilization, and tillage for 1989.................. 11 3 Dry matteryield ofalfalfa and birdsfoot trefoil as influenced by year and location.................................................................................................................................... 15 4 Dry matteryield ofsweet sorghum and sorghum-sudangrass as influenced by species and tillage................................................................................................................... 21 

### 5 Drymatteryield ofsweet sorghum and sorghum-sudangrass interseeded into tall fescue as influencedby herbicide application and sorghum species in 1987.......... 23 6 Drymatteryield ofsorghum as influenced by species and cutting management......... 25 7 Drymatteryield ofwarm-season perennial grasses, alfalfa, and sericea lespedeza in 1989.................................................................................................................... 28 8 Drymatteryield ofbig bluestem and switchgrass at the PurdueAgronomy Farm...... 29



### viiABSTRACf 

### Management ofherbaceous biomass crops must be investigated concurrently with the development ofcost-effective conversion processes. Ourobjectivewas to evaluate the agronomic feasibility ofseveral combinations ofspecies and management systems for producing herbaceous biomass on sites ranging from good to marginal cropland. Soil 

### organic matter and aggregate stability were not adversely affected by any ofthe management options. Ofthe perennial grasses and legumes investigated, switchgrass showed the most potential as a biomass candidate. It has 

### minimum fertilizer inputs, is very persistent, and is effective in reducing soil erosion. Sorghum double-cropped with winter annual rye was 

### very productive, but required more inputs than switchgrass. Interseeding sorghum into perennial grasses was not aviable option, due to its great dependence on environmental variables. Photoperiod-sensitive and hybrid sorghums able to utilize an entire growing season were very productive, with yields up to 39 Mg hal. Two harvest per season resulted in lowyields, such that lodging resistance must be

### incorporated into desirable genotypes through breeding, instead ofusing multiple harvests to prevent lodging. Plant compositionwas greatly affected by species, with a wide range in composition across sorghum genotypes. Ofall species evaluated, switchgrass and sorghum have the greatestbiomass potential, and both ofthese species can be improved to produce higher yields ofa more desirable chemical composition through plant breeding.
CHERNEY, J.H., K.D. JOHNSON, J.J. VOLENEC, E.J. KLADIVKO, and D.K. GREENE. Evaluation ofPotential Herbaceous Energy Crops on Marginal Croplands: 1)Agronomic Potential. 1990. ORNL/Sub/85-2741/5&P1. Oak Ridge National Laboratory, Oak Ridge, Tennessee. 43 pp.

ixINTRODUCTION As technology for economically converting biomass from herbaceous crops to energy is developed, methods for cost-effective production ofherbaceous biomass crops need to be investigated. Ouroverall goal was to evaluate the agronomic and economic feasibility ofseveral combinations ofspecies and management systems for producing herbaceous biomass on a range of cropland sites, from good to marginal cropland. This report concerns the agronomic potential of producing herbaceous biomass. Although grain crop residues are a potential biomass source, estimates indicate that in the U.S. only 80 million tons ofcrop residues can be harvested annually without creating a serious soil erosion problem (OTA, 1980). Erosion currently is a serious problem on marginal lands that are being row cropped. Marginal lands can be grouped into two types. The first is land that is tillable on an annual basis, but soil and/or climate limitations restrict its usefulness for grain crops. It is desirable to provide ground cover throughout theyear on this type ofland in orderto avoid sheet and rill erosion. The second type ofmarginal land includes lands which are not tillable on an annual basis due to erosive, rough, or hilly terrain. Herbaceous crop species under consideration for potential biomass utilization should produce economically acceptable yields while at the same time minimizing soil erosion. Forage crops are ideal for this purpose. There is a broad range in diversity among forage crops. Forages may be annual or perennial in habit, cool season orwarm season, and grass orlegume. Some annual species have a short growing season such that they can be preceded by a winter annual species, thus producing two crops in one season. It also is possible to interseed an annual species into a dormant perennial species to increase annual production. Forage crops fit well into a biomass production scheme. They are adapted and presently grown on marginal as well as productive land, and their production technology is familiar to farmers. Labor and machinery needs fit well with other farming operations, and equipment for harvest and storage ofthese forage crops is available on most farms. Crop management practices for forage species have stressed a high quality product for livestock feed. Previous research in this area is not applicable to biomass production, since quality and yield are inversely related (Cherney and Marten, 1982). Due to inherent variation in marginal land sites, several locations and environmental conditions are necessary to evaluate the agronomic feasibility ofvarious cropping systems.

### 2 Chemical composition ofherbaceous cropswill become importantwhen one ormore economically feasible conversion processes become available for herbaceous crops. Forage plants consist ofa nonstructural and a structural component, and have a compositionvery different from woodybiomass species. Soluble materials include protein, sugars, and pectin. Structural material (fiber) canbe separated into its majorcomponents including cellulose, hemicellulose, and lignin. Since the**~ideal"** composition ofa biomass crop is not known, it is necessary to determine chemical composition ofall potentialbiomass crops. This informationwill beveryimportant in selecting species to fit various conversion options. OBJECTIVES Our overall agronomicobjective was divided into six specific objectives: 1. Determine the biomassyield and chemical composition oftall fescue (Festuca arundinacea Schreb.), reed canarygrass (Phalaris arundinacea L.), switchgrass (Panicum virgatum L.), alfalfa (Medicago sativa L.), and birdsfoot trefoil (Lotus corniculatus L.) when grown under several levels offertilization on marginal sites. 2. Determine thebiomass yield andchemical composition ofwinter rye and sorghum [Sorghum bicolor 

### (L.) Moench.] in a double-cropping system. 3. Determine the feasibility ofinterseeding sorghum into tall fescue orreed canarygrass sod withandwithout herbicides, afterbiomass ofthe cool-season grasses has been removed in the spring. 4. Determine the production potential ofphotoperiod-sensitive and insensitive sorghums compared to sweet sorghum, sorghum-sudangrass, and corn (Zea mays L.). 

### 5. Determine the persistence andyield potential ofsericea lespedeza**~pedeza** cuneata (Dumont) G. Don],weeping lovegrass [I:;ragrostis curvula (Schrad.) Nees], and big bluestem (Andropogon gerardii Vitman), compared to switchgrass and alfalfa. 6. Compare the relative productivity ofbigbluestem and switchgrass in established stands.

### 3 

### PROCEDURES Species Selection We selected grass and legume crops representative ofa large range ofspecies. Cool-season perennial grasses produce a majority oftheir biomass in the spring, with a significant amount of growth in the fall. Tall fescue and reed canarygrass were chosen from this category for the following reasons. Tall fescue is already established on millions ofacres in the Midwest/Lake States area, and represents a commonly grown species. Reed canarygrass is less commonly grown, but is extremely well adapted to marginal sites. It has seen limited use as livestock feed, because herbage alkaloids make it unpalatable. Use ofthis grass is increasing, with the recent release oflow alkaloid cultivars. Reed canarygrass has outproduced other perennial grasses on marginal lands two fold (Cherney et al., 1986). It

### is adapted to wet and dry conditions, and has produced high yields from southern Indiana (Cherney et al., 1986) to Northern Minnesota (Marten et al., 1980). Warm-season perennial grasses have excellent potential for producing biomass, since they have the 

## c4 photosynthetic pathway and are very productive during the warm, dry summer months. These grasses complement the harvest ofthe cool-season grasses because their harvest is at a different time during the growing season. This may be an important economic consideration for the biomass crop producer and the biomass conversion plant. We selectedpvitchgrass for this study, since it is capable ofveryhigh yields with a single harvest peryear and is a warm-season grass adapted to the entire Midwest/Lake States region. It

### is avigorous grass which will produce better growth on droughty, infertile, eroded soils than most grasses, and has been used extensively for erosion control (}:Ieath et al., 1985). Perennial legumes can fix their own nitrogen, and have the advantage ofnot requiring an expensive nitrogen fertilizer source. Legumes also are useful for control oferosion. A disadvantage oflegumes is that most need to be periodicallyreseeded. Alfalfa and birdsfoot trefoil were included in the study as representatives ofthe perennial legume group. Alfalfa is generallyvery productive on good agricultural sites. Birdsfoot trefoil is less productive, but is more tolerant ofacid orwet soil conditions, and has the ability to reseed itselfunder the proper management. Annual grasses, such as sorghum, can be very productive, but require high management inputs and can have serious erosion potential. A method ofreducing erosion is to doublecrop two species, thus maintaining a cover on the soil surface for most ofthe year. Therefore, we evaluated a4 sorghum·sudangrass hybrid and sweet sorghum as summer annual grasses doublecropped with winter annual rye. Anothermethod ofmaximizing biomass productionwhile minimizing erosion potential is intercropping, orgrowing two crops together simultaneously. The two crops must be compatible, and the crops must be managed such that oneorthe other is not eliminated from the stand. Cool· season grasses, although productive inthe springand fall, are usually semi.dormantduring thehot summer months. We no· till planted sorghum intothe cool-season grasses in orderto increase biomass production ofa cool-season grass stand duringthe summer months. Photoperiod-sensitive genotypes will generally not set seed under Midwest conditions, butwill continue to growvegetatively until experiencing freezing temperatures. Therefore, yield canbe maximized by utilizing the entire growing season. Lodging potential must also beevaluated, since some genotypes reach a height of6 meters. Two species which arevery productive in the southern U.S. are sericea lespedeza andweeping lovegrass. Their area ofadaptation extends to the southernboundaryoftheMidwest. Ourgoal was to determine ifthese specieswould persist in Indiana, and iftheywould be as productive as in the southern U.S. Based on past studies, the only warm-season perennial grass which might be as productive as switchgrass in theMidwest is bigbluestem. We used established stands ofswitchgrass andbig bluestem to compare theirrelative productivities. Site Selection Five siteswere selected in Indiana to represent a range from good to marginal cropland. Organic mattercontent ofthe soil from thefour sites ranged from 1.5 to 3.7% ofsoil dry weight. Site 1 is located in west central Indiana at the Throckmorton PurdueAgricultural Center 

### (TFLA 

### 1). It is located on a soil which has a minimum ofrestrictions to agricultural production, and has a slope near zero. The soil type is a Sidell ('l)picArgiudoll, fine-silty, mixed mesic) silt loam with a 0 to 2% slope. The previous crop on this sitewas conventionally-tilled corn. Itis considered very good to excellent agricultural land, and is representative ofthe large acreage ofland in the Midwest dedicated to row-crop farming.

### 5 Site 2 is also located in west central Indiana at theThrockmorton PurdueAgricultural Center (T-SLOPE) and is on a similar soil type as Site 1with less organic matter, and a previous cropof conventionally-tilled com Its major restriction to production is that it is on a 6 to 8%slopewith erosion problems. Site 3 is located at the southeastern Indiana Purdue Agricultural Center (SEPAC) on a soil very similar to areas in southern Ohio and southern Illinois. The soil type is a Cincinnati (Typic Fragiudalf, fine-silty, mixed, mesic) silt loam. The soil has a fragipan which makes it difficult to drain and restricts rooting depth. The 8 to 10% slope creates severe erosion problems due to the poorly structured silt loam surface. The previous crop

### was conventionally-tilled corn. Site4 is located in a very hilly region ofsouthcentral Indiana at the Southern Purdue Agricultural Center (SIPAC). The soil type is a Zanesville (Typic Fragudalf, fine-silty, mixed mesic) silt loam. 'This area is similar in topography to southwest Wisconsin and other hilly areas in the Upper Great Lakes Region. The silt loam soil has a dense, brittle fragipan and an 8 to 12% slope with prior erosion. Theslope and soil characteristics make this poorcropland. Tall fescue 

### was the previous crop on this site. Site 5 is located in west central Indiana at thePurdue Agronomy Farm on good agricultural soil with 0 to 2%slope. Thesoil type is Chalmers (Typic Haplaquoll) silty clay loam. This site

### was chosen for comparison ofswitchgrass and bigbluestem in 1988 (Objective 6), since both had been previously established at this site.

Perennial Crops. Tall fescue ('Forager'), reed canarygrass ('Venture'), switchgrass ('Cave-inRock'), alfalfa ('Hi-Phy'), andbirdsfoot trefoil ('Fergus') were planted at all four sites in the spring of 1985. A randomized completeblock design with four replicates 

### was used, with a split plot arrangement for fertilizer treatments. Individual plot size was 2.43 X 6.10 m. Establishment of grasses at some locations failed in 1985, and they were replanted in 1986. In 1986-89established grasses received 0, 50, 100, 150, or200 kg N ha· 1 in the spring. Tall fescue andreed canarygrass were harvested in lateMay and in early September. Switchgrass

### was harvested once in mid-July. In 1989, switchgrass regrowth 

### was sufficientenough for a second harvest afterfirst frost. Legume standswere fertilized with 0, 100, or200 kg potassium ha •1 in late

### 6 March, since potassium is usually the most limitingelement for legume biomass production. Alfalfa was harvested three times peryear, in earlyJune, mid-July and late August. Birdsfoot trefoil was harvested twice, in earlyJune and late August, allowing reseeding to occur. Harvesting was accomplished with a flail-type harvester. Doublecropping Sorghum and Winter Rye. Sorghum-sudangrass ('FFR-201') and sweet sorghum ('M81E') were conventionally sown in mid-May, 1985 using a randomized completeblock design with four replicates. In succeeding years (1986-88) one halfoftheplots were conventionally sown and one halfwere no-till sown. Four rates ofnitrogen fertilizer, 0, 50, 100, or 150 kg N ha· 1 were applied atseeding. Therewas a split-split plot arrangement ofthe treatments,with tillage as the whole plot, species as the sub-plot and fertilizer as the sub-sub-plot. Herbicide (2,4-DB) was applied for the control ofbroadleafweeds as necessary. Sorghum-sudangrasswas harvested once in early September at a mature grain stage, and sweet sorghum was harvested once in early October at a flowering to early grain stage. Yields included both grain and stover components ofplants cut 

### 5 em above the soil surface. Winter annual rye was no-till seeded into the sorghum stubble in early October 1985-88, and 50 kg N ha· 1 was applied to the rye crop in the spring. Rye was harvested with a flail harvester at anthesis in mid-May and sorghum was eitherconventionally sown after tillage or no-till sown into the rye stubble. lnterseeding ofSorghum intoPerennial Grasses. In the springof 1986 and 1987 after the harvest oftall fescue and reed canarygrass, sorghum-sudangrass and sweet sorghum were no-till sown into the established perennial grass sodswith the addition of0, 100, or 200kg N ha· 1

. One halfofthe plotswere treatedwith paraquat to delay any growth ofthe perennial grass until the sorghum had become established. As with the otherexperiments, the individual plot size for each treatment combinationwas 2.43 X 6.10 m and the design was a randomized completeblockwith 4 replicates. Treatments were arranged in a sp1it-split-split plot, with sorghum species as the sub-plot, herbicide treatment ofthe perennial grass sod as the sub-sub-plot, and nitrogen fertilizer as the subsub-sub-plot. Sorghum was hand-harvested inearly September and this was followed by harvest of the perennial grass with a fail harvester. Photoperiod Sensitive and Insensitive Sorghums. Areas atT-FLATand SIPACwere selected for establishing this study, and P, 

### I<, and limewere applied as needed. Both sites were conventionally tilled in early May, 1988 and 1989. Sweet sorghum, sorghum-sudangrass, several7 

### tropical sorghums and one hybrid forage sorghum were sown in three replicates offour row, 6.1 m plots at both locations in 1988. Two rates ofN fertilization (100 or 200 kg N ha*1) were applied. Hybrid corn ('Pioneer 3475') was 

### sown to measure corn grain potential at the sites. Sorghumsudangrass was sown with a 20.3 em row spacing and harvested twice during the season in an attempt to increase its production. Since sorghum-sudangrass has not been competitive with sweet sorghum when cut once and doublecropped with rye, it was 

### managed to utilize more ofthe growing season. All other species were harvested once in early October, prior to a killing frost. For analysis, species were thewhole plot, with nitrogen rates as a subplot. In 

### 1989, sorghum-sudangrass was not sown, but more hybrid forage sorghums were added to the study. Also in 1989, all sorghum species were harvested either one to two times. Two-cut sorghums were harvested in

### July and in early October, one-cut sorghums were harvested in early October. For analysis, harvest management was thewhole plot, with species as a subplot, and nitrogen rate as a sub-subplot. Yield and Persistence ofSouthern U.S. Species. Areas at T-FLAT and SIPAC were selected, and P, K, 

### and lime were applied as required by soil test. Sites were conventionally tilled and alfalfa ('Hi*phy') and sericea lespedeza ('Serala') were sown in mid-April, 1988. The first week ofMay switchgrass ('Cave-in-Rock'), big bluestem ('Kaw'), and weeping lovegrass ('Ermelo') were sown. Alfalfa, switchgrass, and big bluestemwere sown for comparison with the two southern U.S. species. Plot areas were irrigated at both sites to aid establishment. All species were successfully established at T-FLAT, but weeping lovegrass and big bluestem needed to be resown in the spring of 1989. Three nitrogen rates were applied to grasses (0, 100, and 200 kg Nha-l). In 1989, alfalfa and weeping Iovegrass were harvested three times, switchgrass and sericea lespedeza were harvested twice, and big bluestem

### was harvested once. Big Bluestem Compared to Switchgrass. Five-year-old stands of'Kaw'big bluestem and 'Cavein-Rock' switchgrass at the Purdue Agronomy Farm were used for this portion ofthe study, starting in 1988. Plot areas were fertilized with 0, 100, or 200 kg Nha-l. Switchgrass was harvested once in lateJuly or early August, 1988 and 1989, and big bluestem was harvested once per season two weeks later than switchgrass. Species were considered whole plots for statistical analysis, with nitrogen rates as subplots.

### 8 

### Compositional Analyses Samples ofherbage were collected and dried at 6fP

### C to determine dry matter content for calculation ofyields. Subsamples were ground and analyzed for structural and nonstructural components. Compositional analyses are reported on a 105° Cdry weight basis. Nonstructural Components. Nitrogen content ofsamples

### was determined using a microKjeldahl technique. Nonstructural carbohydrates were extracted with deionized water from fructanstoring species (cool-season grasses, including rye), orwere hydrolyzed using amyloglucosidase for starch-storing species (legumes, switchgrass, and sorghums). In 1988, pectin content 

### was determined. For pectin analysis, samples (0.1 g) were incubated overnight at 4()0C with pectolyase (5 mg) in 20 mL ofpH4.6 acetate buffer. Standard reagents (for a uronic acid analysis) were added and readings were taken at 520 nm. Pectin content was determined based on galacturonic acid as a standard. All components were reported on a dry weight basis. Structural Components. The detergent fiber methodwas used to quantify (gravimetrically) concentrations offiber and structural cell wall components. The neutral detergent fiber (NDF) procedure was used 

### to separate fiber and soluble cell components (including pectin), and an acid detergent fiber procedurewas used to remove hemicellulose from the fibrous neutral detergent residue. Lignin was oxidized and removed with permanganate, and samples were ashed to determine cellulose by difference. In 1988, plant silica values were determined using a modified sequential fiber procedure. Neutral detergent can not be used, since it solubilizes plant silica. Samples were treated with acid detergent, and residues were extracted with permanganate and then ashed. The ash was treated with 40% HBr toremove anything remaining in the sample that was not silica (primarily other minerals). The sample was ashed a second time and silica content was determined as the remaining sample weight. Soil 

### Analysis. Standard soil tests were taken eachyear to determine whether lime, phosphorus, orpotassium addition was necessary. In 1985, 1987, and 1989 soil samples were taken for organic matter and aggregate stability analyses. Aggregate stabilitywas determined using a wet sieving technique. Mean weight diameterwas determined and is a measure ofthe average size ofa waterstable aggregate. Statistical analyses presented were derived from separate analyses ofvariance by year.9 RESULTS AND DISCUSSION

Soils were fertilized as required by soil test recommendations throughout the study. One exception to this 

### was the controlled application ofpotassium on legume plots. Organic matter values were reasonably stable throughout the study, averaging 37.3, 19.3, 15.7, and 22.7 g kg-1 dry soil forT-FLAT, T-SLOPE, SEPAC, and SIPAC, respectively. Soils were monitored for aggregate stability in 1985, 1987, and 1989 (Table 1). Aggregate stability is a measure ofsoil stability that is inversely proportional to erodibility. Aggregate stability, measured as mean weight diameter, improved at all three sites where corn had been the crop grown previous to our study. Aggregate stability did not improve at SIPAC, where the land had been in continuous tall fescue for manyyears priorto our study. Ofthe perennial crops grown, tall fescue and reed canarygrass resulted in significantly higher aggregate stability, with no difference between switchgrass, alfalfa, and birdsfoot trefoil. Doublecropping ofsorghum and rye resulted in similar aggregate stability values as switchgrass (Table 2). High nitrogen fertilization resulted in lower aggregate stability, and no-till planting of sorghum resulted in higher aggregate stability than conventional tillage, as expected. Maintenance ofsoil stability is essential for reducing erosion problems and for maximizing crop productivity. These results indicate that perennial, sod-forming crops will tend to increase soil stability more than annual row crops. Sorghum doublecropped with rye, however, resulted in improved aggregate stability over conventional corn production. Objective 1 - Perennial Grass and Legume Production Production Potential ofGrasses. In general, switchgrass (Fig. 1) produced more dry matter with one harvest peryear than tall fescue (Fig. 2) or reed canarygrass (Fig. 3) with two harvests. Switchgrass and reed canarygrass were more difficult to establish, !ndwere notwell enough, ..:etablished to measureyields at SIPAC until1988. In 1989, switchgrass regrowth in late fall was

sufficient enough for a second harvest after a killing frost. This resulted in significantly largeryields for switchgrass in 1989, averaging over 16 Mg dry matter ha-l at SIPAC. The drought of 1988 reduced yields to 20 to 30% ofa normal year.Table 1.

1985 1987 1989

1989 10

Aggregate stability (meanweight diameter, MWD) ofsoil as influenced by location and species.

Location T-FLAT T-SLOPE SEPAC SIPAC

------------------------- mm ------------------------ 0.65 0.73 0.71 1.95 1.07 0.89 1.46 2.61 2.42 1.79 1.70 2.21

Species Alfalfa 

### BFT Tall Reed Switch BLSDa fescue canarygrass grass

------------------------------------ mm ------------------------------------ 1.54 1.89 2.31 

### 2.38 1.72 0.36

a Bayes least significant difference (P approximately0.05).

## •

•



# .. Table2. 11
Aggregate stability (mean weight diameter. MWD) ofsoil in doublecropsorghum plots as influenced by location. nitrogen fertilization• and tillage for 1989.
Location T-FLAT T-SLOPE SEPAC SIPAC

--------------------------------- mm ---------------------------------- 1.89 1.95 1.16 1.44 0.46

Nitrogen applied to Sorghum. kg N ha-l 0 150 Significanceb

----------- mm -----------

1.75 1.47 **

Tillage Conventional No-till Significanceb

----------- mm ------------

1.17 

### 2.04 **

a Bayes least significant difference (P approximately 0.05). b **Significant atP 

### < 0.01.

## 20 

## 18 16 

# •14 .c 

## Ci.12 :& 

## .g-10 

# ! 8 

# > 6 4 

## 2 0 12



### ... 0 ........50.... . 100 ....150 

### >1 .....

# ~.... -.-



## 1986 1987 1988 1989 Figure 1. Switchgrassyield response to nitrogen rertilization (0, SO, 100, 150, and 200 kgN ha•1). Means orrourreplicates and one location in 1986, three locations in 1987, and rourlocations in 1988 and 1989. 

# ..



# ..

### 13 

## 20 ...... 0 50 ...... .. 100 . ........... 150 . . . 200. 

# ... 18 

# li l

# HH**...,..~H** 

# ... ...
. . ·- ---



## 1986 1987 1988 1989 Figure 2. Tall fescue yield response to nitrogen fertilization (0, 50, 100, 150, and 200 kg N ha•1). Means offour replicates and two locations in 1986 andfour locations in 1988-89.



### .. .. . .. ..........100.... . 150 .............2.0.0....**~...,.,.,....,** 

# ...... ...

••••••• • •••••••••••• ««««««««< « ""



## 1986 1987 1988 1989 Figure 3. Reed canarygrassyield response to nitrogen fertilization (0, 50, 100, 150, and 200 kg N ha•1). Means offour replicates and one location in 1986, threelocations in 1987, and four locations In 1988 and 1989.

### 14 Theyield response to nitrogen fertilization was predictable in tall fescue (Fig. 2) and reed canarygrass (Fig. 3). Switchgrass, however, required much less nitrogen for high yields, and even produced acceptableyields with no nitrogen fertilizer applied (Fig. 1). Some nitrogen fertilizer is necessary for high yields when switchgrass is harvested twice peryear. Since N fertilization is a high cost input, the relatively large yields ofswitchgrass in one harvest with minimum fertilizer input give this grass a high potential as a biomass species. Production Potential ofLegumes. Alfalfa yields were high on good cropland, butwere much lower on marginal cropland sites (fable 3). Since alfalfa is drought resistant, yields were not as negatively affected in 1988 as in the perennial grasses. Alfalfa produced as much as 17Mg dry matterha
-1, but required three harvests and periodic insect control to achieve these yields. Birdsfoot trefoil produced considerably lower yields than alfalfa except at SIP AC (fable 3). Trefoil is more tolerant ofless than optimum environmental conditions, and was not damaged by plant heaving during the spring as was alfalfa. Alfalfa also was damaged by deer grazing at SIP AC, resulting in lower harvested yields. Neither alfalfa norbirdsfoot trefoil responded topotassium fertilization at any ofthe four sites. Since legumes typically remove a large quantity ofpotassium from the soil, this lack of response was probably due to thehigh concentration ofpotassium initially present in the soil at all four sites. Although depletion ofpotassium leading to a yield response with potassium fertilization was expected, it did not occur. Plant Composition. Herbaceous biomass has a composition very different from woody biomass species. The composition also changes greatly as the plant matures, and composition ofimmature herbaceous plants is considerably different from the more mature plants harvested in this study. Boiling in neutral detergent with ethylenedinitrilo-tetraaceticacid (EDT A) removes soluble materials, including pectin, from the herbage. The remaining fiber (neutral detergent fiber, NDF) can be separated into its major components. Cellulose, hemicellulose, and lignin can be estimated gravimetrically. Crude protein concentration was estimated by multiplying the nitrogen concentration by 6.25 (based on the average nitrogen content ofa protein). Nonstructural carbohydrates (CHO) were determined, as well as pectin and silica on 1988 samples. The remaining unaccounted soluble dry matterwas termed 'othersolubles'. This component contains tannins and other soluble phenolics,

### 15



### Table 3. 

### Dry matteryield ofalfalfa and birdsfoot trefoil as influenced by year and location.

1986 1987 1988 1989

1986 1987 1988 1989 

### Alfalfa 

### T-FLAT T-SLOPE SEPAC SIPAC

----------------------------- Mg ha•1

---------------------------- 

### 14.56 13.19 9.29 7.89 1.97 14.68 13.56 11.30 6.92 2.24 17.36 13.28 9.98 1.62 2.78 12.87 13.28 9.94 8.71 1.04



### Birdsfoot Trefoil 

### T-FLAT T-SLOPE SEPAC SIPAC

-------------------------------- Mg ha•1

--------------------------- 

### 3.96 5.28 7.31 6.21 1.21 6.26 6.32 6.24 7.59 0.90 8.03 

### 3.72 6.31 4.51 5.88 

### 5.72 

### 5.25 7.74 1.41 

### 0.46

a Bayes least significant difference (P 

### approximately 0.05).

### 16 plant pigments, lipids, soluble minerals, and other components. Switchgrass is very high infiber, over 700 g kg- 1 dryweight. It has very little silica and pectin, with approximately equal amounts oflignin, crude protein, and soluble CHO (Fig. 4). Herbaceous grasses tend to have similar amounts ofcellulose and hemicellulose, with relatively small amounts of lignin, compared to woody species. Tall fescue and reed canarygrass contained lower amounts of fiber, and were higher in crude protein, CHO, and silica, as compared to switchgrass (Fig. 5). Tall fescue was similarto reed canarygrass and the data is not shown. Alfalfa and BFrwere similar in composition (Fig. 6-7), and differed significantly from the grasses. Legumes typically contain twice as much cellulose as hemicellulose, and arehigher in lignin and crude protein than grasses. They also are lower in total fiber than grass,es, with a large undefined neutral-detergent soluble component. Composition was not influenced by location or management treatment. Hemicellulosic Suzars and PhenolicMonomers. In 1988, samples were analyzed for neutral hemicellulosic sugars and alkali-labile phenolic monomers using high performance liquid chromatography. Glucose andxylose were the primary neutral sugars detected in all species, with some arabinosepresent (data not shown). The amount ofxylan present is critical to some conversion processes, and it does vary across species. The major alkali-labile phenolic monomers present includedp-coumaric acid and ferulic acid. In general, grasses contained approximately 10times more alkali-labile phenolics than legumes. Switchgrass contained over 10g kg-1 dryweight ofthe two major phenolics. Theimportance ofthese phenolics to conversion will depend on the particular conversion process. Objective 2- Production ofSorghum Doublecroppedwith Winter Rye WinterAnnual Rye. Rye was no-till planted in the fall ofeach year and harvested at a flowering stage in the spring priorto sorghum planting. Rye dry matteryields were low and relatively consistent across years, except for the drought year of 1988 (Fig. 8). Rye yields were influenced by previous nitrogen fertilizer applications to sorghum, with a slight but consistentyield increase with N fertilizer applied each year. Rye yields also were affected by location. Sweet Sorghum and Sorghum-sudangrass. Sweet sorghum and sorghum-sudangrass were planted in conventionally-tilled and no-tilled areas, and herbicides were applied as needed to control

### 17



### Cellulose 

### (29.2%)

Silica Figure 4. Switcbgrass composition, 1988.



### Cellulose 

### (23.7%)
Silica Pectin (0.7%) Lignin 

### (6.6%) Crude Protein 

### (6.3%) Nonatructural CHO 

### (5.3%)

Pectin (0.7%) Lignin 

### (5.2%) Crude Protein (11.3%)

Nonstructural CHO (10.9%) Other Solubles (14.8%) Figure S. Reed canarygrass composition, Harvest Date 2, 1988.

### 18 

### Pectin (8.7%) Hemicellulose Crude Protein (20.9%)

Nonstructural CHO (2.8%) Cellulose (20.3%) Other Solubles (29.2%) Figure 6. Birdsfoot trefoil composition, Harvest Date 2, 1988.



### Pectin Hemicellulose Crude Protein (17.3%)
Cellulose (25.5%) ·Nonstructural CHO (4.5%)
Other Solubles (25.2%) Figure 7. Alfalfa composition, Harvest Date 3, 1988.

## 5.5



# -

I 

# c 5.0 

# .r::.**~4.5**


# .. "C 

## 4.0 Q) 

# ·- >- 3.5 3.0 19



# ... o 1989 

# ·····································.·.·.·o-..........::. ··· ·t986·· •· _,'Y 

## 1987

• • • • • • • • • • • • • • • • • • ' • • I : : 

# 0..:• •

•

••

•

•

•

• ·, • ••

•'.1/1' • ,"':: • • • • • • • • • • • • • • • • • ····· 'Y - - -'Y 

# - 

# -

........... . ""!'

. ..........•..•.•......•••..............••••••••••....



# ................................................:::::=--. !988.. ••••••• 

## •·•·•······· 0 ............. 

## 50 100 -1 

# Nitrogen, kg N ha 150

Figure 8. Winterannual rye 

### yield response to 

### nitrogen fertilizer carryover from applications to 

### sorghum in previons years.20 grasses and broadleafweeds. Sorghum-sudangrass was mature (ripe grain stage) at all sites by the first week ofSeptember and was harvested at that time. It had accumulated essentially all ofits dry matter at that time, andwas removed before lodging became a problem. Sweet sorghum was harvested at all sites during the last week ofSeptember to the first week ofOctober, to allow enough time to get rye established at the sites. Sweet sorghum was in a flowering to a seed stage at harvest. Sweet sorghum yielded approximately 30% moredry matter than sorghum-sudangrass in all years except the drought year of 1988 (Table4). Part ofthis**incr~sed** yield was d.:ue to the longer growing season for sweet sorghum. Sorghum yield was not greatly affected by tillage treatment, indicating that the no-till method may be superior from thestandpoint ofproductioncosts and soil erosion. Biomass yields ofthe doublecrop system exceeded 31 Mg dry matterha· 1 at high N fertiHzer rates. There was a consistent sorghum yield response to N fertilizer in 1985 and 1986, but was not as evident in 1987 and 1988 (Fig. 9). The drought of 1988 resulted in extremely low dry matteryields at two ofthe sites, producing a very low average yield for 1988. Thedecline in average yield from 1985 to 1987 (Fig. 9) may be theresult ofhaving sorghum in monoculture. Objective 3 - Production ofSorghum Interseeded in Perennial Grasses Sweet sorghum and sorghum-sudangrass were interseeded into tall fescue andreed canarygrass sod at two sites in 1986 and four sites in 1987. Paraquat treatment was effective in reducing competition oftall fescue (Table 5), butwas not effective with reed canarygrass. Yields of sorghumwere unacceptably low. Although it was possible to establish sorghum in 

### a reed canarygrass stubble, competition from the reed canarygrass prevented the sorghum from developing into a significant yield component. Interseeding ofsorghum into tall fescue was highly dependent on site and environmental conditions. Thebest combination oftreatments was sorghum-sudangrass, paraquat treatment, and fertilization at 200 kg N ha
-1

. This combination does not compare favorably to a management oftall fescue alone with 200 kg N ha
-1 fertilization. The secondyear ofinterseeding (1987), high N fertilization plus paraquat treatment damaged the tall fescue stand at SIPAC. Due to its dependence on environmental conditions and the need for a high level ofmanagement inputs, interseeding is not a viable option for biomass production.Table4.

1985 1986 1987 1988

1985 1986 1987 1988 21


### Dry matteryield ofsweet sorghum and sorghum-sudangrass as influenced by species and tillage.
Species Sorghum-sudangrassSweet sorghum

---------- Mg ha-1

--------

16.4 22.2 12.6 19.1 10.6 15.8

8.3 8.9

Tillage Conventional No-till

--------- Mg ha
-1

-------- 18.0 16.8 12.5 9.0 14.8 13.8 8.2 Significancea


###   **  **

Significancea



###   **  a** Significant at P 

### < 0.01.Cll 

## 18 .



# ~16 :E 

## 14 

# :i 12 

# •
·- 10 

# > 8 6 

## 4 2. 0 

## 1985 22

H • 

### 100 • ••• •••• 150 

# ··--

1986 

## 1987 1988 Figure 9. Sweet sorghum yield response to nitrogen fertilization (0, 50, 100, and 150 kg N ha-1) averaged over four replicates, four locations, and two tillage treatments.TableS.

T-FLAT T-SLOPE SEPAC SIPAC

T-FLAT T-SLOPE SEPAC SIPAC 23


### Dry matteryield ofsweet sorghum and sorghum-sudangrass interseeded into tall fescue 

### as influenced by herbicide application and sorghum species in 1987.

Herbicide No Paraquat Paraquat



### --------- Mg ha-l
-------

0.12 0.68 0.03 

### 0.20 0.27

Species 0.32 2.32 3.31 Significance 8


# •• •• 

# •• ••

Sorghum-sudangrass Sweet sorghum Significancea



### --------- Mg ha-l
-------- 0.66 0.14 

### 0.25 0.10 1.28 2.12 1.24 1.46 

# • ** NS NS


### a • 

## ** , Significant at P 

### < 0.05 and P 

### < 0.01, respectively.24 Objective 4- Production Potential ofPhotoperiod-Sensitive and Insensitive Sorghums Two locations (T-FLATand SIPA

### C) were selected for this objective, and arange ofsorghum genotypes was planted in 1988 and 1989. Five commercial hybrid forage sorghums were included with the photoperiod-sensitive genotypes in 1989. Both 100 and 200 kg N ha- 1 treatments were applied, with some differences in yield due to nitrogen fertilizer. Genotypes also were harvested either once ortwice during the season in 1989. This was done to see ifyield could be maintainedwith two harvests, while at the same time reducing the problem oflodging. Dry matteryields were high during the drought ofl988,yielding up to 33 Mg dry matter ha-1 in replicated trials (data not shown). Hybrid com planted at the same time did not have a significant grainyield, and total dry matteryields were4 to 5 Mg dry matter ha-l. This studywas sown in early May, which was early enough in the spring to take advantage ofsoil moisture available, and stands were excellent. This is in contrast to sorghum plantedin late May, 1988, under Objective 2, which was greatly affected by the drought. Sorghum-sudangrass was included in this trial in 1988, in orderto determine iftwo harvests per year would extend its growing season such that higheryields would result. Two-harvest yields of sorghum-sudangrass in 1988 were not different from one-harvestyields in past years, making sorghum-sudangrass a less attractive biomass option than sorghum. Additionalcommercial sorghum hybrids were added to the study in 1989 and a total of 11 sorghum genotypes were studied. Two-harvest yields were significantly lower than one-harvest yields in all cases (Table 6). Higheryields were produced at the T-FLATsite, and replicatedyields for one variety ('Sucro Sorgo 506') reached 39Mg dry matter ha-1

. Genotypes ranged from 0 to 25%ofthe dry weight as grain. Plant heights ranged from 2.2 to 5.5 m. Therewas a considerable range in plant lodging resistancewith 'Grassl' the most susceptible to lodging. Sweet sorghum and 'Vartan' genotypes also were susceptible to lodging. Plant Composition. A considerable range in composition exists in sorghum (Fig. 10-11). Neutral detergent fiber content ranged from 543 g kg-1 dry weight in sweet sorghum to 730 g kg· 1 dry weight in 'Vartan 2319'. This large range in composition coupled with the range in lodging resistance indicates that there is considerable potential for improving sorghum's composition and lodging resistance. Compositionwas not greatly influenced by location or nitrogen fertilizer level.25

Table6. Dry matteryield ofsorghum as influenced by species and cutting management in 1989.a

OneHarvest Two Harvests
Dekalb-Pfizer 'FS25E M-81E sweet sorghum Vartan 2319 Grassl Vartan3192 PAG 'FS-466' Purdue Hybrid Funks 'G1990' Pioneer '931' Vartan 3 NK 'Sucro Sorgo 506' BLSDb (one value applies tobothcolumns) -------- Mg ha-l
------ 25.56 17.43 27.48 15.61 21.39 12.80 25.72 15.52 25.97 15.44 

### 23.11 16.28 15.94 31.45 15.25 30.51 19.04 27.05 32.95 18.02 6.1

a The 'Purdue hybrid' and 'Vanan 3'were harvested onceonly, due to a shortageof seed. b Bayes least significant difference (P approximately0.05).26



### Crude Protein {5.1%)

Cellulose (24.5%) Nonslructural CHO (20.5%)

Silica (18.1%) Figure 10. Sweet sorghum ('M81E') stovercomposition, 1988.



### Cellulose (35.1%) Pectin (1.3%) Lignin (7.4%) Crude Protein (6.3%) Silica (1.5%) Other Solubles 

### (10.7%) Nonstructural CHO 

### (7.4%) Figure 11. Sorghum ('V2319') stovercomposition, 1988.

### 27 Objective

### 5
- Yield and Persistence ofSouthern U.S. Species The high producing southern U.S crops, weeping lovegrass and sericea lespedeza were studied for persistence andyield at T-FLATand SIPAC. Big bluestem, switchgrass, and alfalfa also were included for comparison. Standswere established in 1988, with re-establishment ofgrasses in 1989 required at SIP AC. Switchgrass outyielded theothergrasses in 1989 atT-FLAT (Table 7). Lovegrass stands survived thewinter inexcellent condition atT-FLAT, and three harvests were taken in 1989. Lovegrass stands at SIP ACdid not survive thewinter. Indiana is at the northernmostboundary for lovegrass survival, and it is questionable whetherornot itwill persist this far north. Sericea lespedeza is adapted to southern Indiana, and outyielded alfalfa at SIPAC (Table 7). When land is suitable for alfalfa as at T-FLAT, however, lespedeza will not produce more biomass than alfalfa. Objective 6
- Relative Productivity ofSwitchgrass and Big Bluestem Switchgrass has consistently produced high dry matteryields, with a minimum ofN fertilization. Anotherwarm-season perennial grass with high productionpotential is bigbluestem. Five-year-old established stands ofthese two grasses at thePurdue Agronomy Farmwere used for this study in 1988 and 1989. The stands had no treatments imposed on them previously, andwere fertilized with minimum nitrogen. Switch

### grass 

### was harvested two weeks earlier thanbigbluestem since it matures earlier. A typical patternofyield with nitrogen fertilizer

### was observed. Switchgrass consistently outyielded big bluestem (Table 8), as it did under Objective 

### 5.

### 28

Table7. 

### Dry matteryield ofwarm-season perennial grasses, alfalfa, and sericea lespedeza in 1989.

Big bluestem Switchgrass Weeping lovegrass

Alfalfa Sericea lespedeza T-FLAT

9.0a 15.2 11.5

T-FLAT SIPAC

-------- Mg ha
-1

--------

15.9b 

### 7.9



### 8.6 10.2

a Means ofthree replicates and three nitrogen rates. b Means ofthree replicates and two locations. Significant species X location interaction 

### (P 

### < 0.01).TableS.

1988 1989 29


### Dry matteryield ofbigbluestemand switchgrass at the Purdue AgronomyFarm.
Species Bigbluestem Switchgrass Significancea

---------- Mg ha
-1

--------- 

### 6.8 10.0 

## ** 9.7 11.7 

## **

a 

## ** Significant at P 

### < 0.01.30 SUMMARYAND CONCLUSIONS Soil organic matterwas not adversely affected by the selected crop management systems. Soil aggregate stability improved at three sites which had previous crops ofconventionally-tilled com. Perennial sod-forming grasses improved soil stability more than legumes. High nitrogen fertilization had a negative effect on aggregate stability, and no-till planting ofsorghum improved aggregate stability over conventional tillage. Ofthe perennial species investigated._**switchgr~** 

### li.PJ>C!!J]1Q**hav~.J.h~** most**biom~** ]2Qtenti31 from an agronomic standpoint. With minimum fenilizer inputs and one harvest peryear, it is superior in yield to the other perennial species studied._Switchgrass.J!.elded as much as 16 Mg dry matter ha-l 

### fi:Q!!l two C!lttings**i~_n.** Once established, switchgrass is also very persistent, and a stand will last indefinitely.**~elds** were.Jess affected by drought than otherperennial grasses. Switchgrass was difficult to establish at some sites, and more research needs to bedone to ensure quick establishment. Switchgrass breeding to-date has not stressed maximum biomassyield, and higher production potentiallikely exists. Sorghum double-cropped with winter annual rye was a very productive management option,with yields as high as 

### 31 Mg dry matter ha-l. Sorghum yield was not greatlyreduced under a no-till management system. Sorghum-sudangrass was a less productive option,whetherone or two harvests were taken peryear. This option requires more inputs than with switchgrass, and erosion potential is greater than with switchgrass. Over time, sorghum in monoculture had reduced yields. It would be useful to evaluate sorghum in rotation with othercrops, such as soybeans, to see ifthis effect can be eliminated. Interseeding sorghum into perennial grasses does not appear tobe a viable option for biomass production, due to its great dependence onenvironmental conditions and the need for high level management inputs.**PllQtQ.period::S~nsl!jy~JliUtb)'l>~;idJoJ:ag~ ~rgbum~.** **~J.e** 

### <;;ip!!>le qfpiOducing.

### .v.ery:lligh

### yjelds, with up

### to 39 Mg dry matter ha-l produced jn**r~licaJ¢...Jr!als,.** A two-harvest management resulted in no significant lodging ofplants, butyields were considerably lower than under one-harvest management. A wide range was found in yield, height, grain production, and lodging resistance. Since this management option has great biomass potential, an even larger range ofgermplasm should beevaluated to determine the full potential ofthis species. 'Grassl'was highest yielding in 1988, but 

### •

### 31 

### only an average producer in 

### 1989. It would be useful to evaluate sorghum over a number ofyears to observe response to varying climaticconditions, and with the experience from monoculture of sorghum, in 

### rotationwith other species. Sericea lespedeza and weeping lovegrass are able to survive thewinter in Indiana, but are not as well adapted as other species, and will probably not produce yields which arecompetitivewith species well adapted to the region.**Plll_!!t.J;Q~J>~~i!iQ,J!:"'liS** 

### greatly affected by species, but n()t by location or**manag~ment** ······' """•- ·-- --- --- ----- ..**2reatmen~.** 

### Pectin and crude protein content were generallyhigh in legumes, and silica content

### was higher in grasses than legumes. Sorghum exhibited a very large range in composition across genotypes, and has good potential to

### be modified to suit particular conversion processes. Lodging resistance in sorghum also is 

### relatively easy to transfer to a particular genotype, making modification ofsorghum a viable option for the future.32 REFERENCES Cherney, J. H., Johnson, K D., Lechtenberg, V. L., and Hertel, J. M. 1986. Biomass Yield, Fiber Composition and Persistence ofCool-Season Forage Grasses,

### Biomass 10:175-86. Cherney, J.H., and G.C. Marten. 1982. Small grain crop forage potential: II. Interrelationships among biological, chemical, morphological, and anatomical determinants ofquality. 

### Crop Sci. 22:240-245. Heath, M. 

### E.., Metcalfe, D. S., and Barnes, R. F. 1985. 

### Forages, the Science of GrasslandAgriculture, Ames, Iowa: Iowa State Press. Marten, G. C., Clapp, C. E., and Larson, W. E. 1980. Effects ofMunicipal WasteWater Effluent on Performance and Feed QualityofMaize vs. Reed canarygrass,J. 

### Environ. Quality 9:137-41. Office ofTechnologyAssessment, U.S. Congress. 1980. 

### Energy from BiologicalProcesses, U.S. Govt. Printing Office. 0-65-498. Washington, D.C. OtherPublications Greene, D.K, KD. Johnson,J.H. Cherney, andJ.J. Volenec. 1987. Biomass yield and chemical composition ofsorghum and rye doublecropped on marginal land. 

### Agron. Abst. p. 112. Cherney, J.H.,J. Lowenberg-DeBoer, KD. Johnson, andJJ. Volenec. 1989. Evaluation ofgrasses and legumes as energy resources. 

### Proc. Energy from Biomass and Wastes XII. Feb. 15-19, 1988, New Orleans, LA Institute ofGasTechnology, Chicago, pp. 289-323. Lowenberg-DeBoer, J., and M.A Lopez-Pereira. 1988. Risk assessment for herbaceous biomass crops: Thecase ofperennial grasses. Southern Biomass Conference. July 26-28, 1988, Auburn University. Greene, D.K, KD. Johnson, J.H. Cherney, andJ.J. Volenec. 1988. Biomassyield and chemical composition ofperennial grasses grown on marginal lands. 

### Agron. Abst. p. 127. Cherney, J.H., KD. Johnson, J.J. Volenec, and KS. Anliker. 1989. Chemical composition of herbaceous grass and legume species grown for maximumbiomass production. 

### Biomass 17:215- 238. Lowenberg-DeBoer, J., andJ.H. Cherney. 1989. Biophysical simulation for evaluating new crops: The case ofswitchgrass for biomass energy feedstock. 

### Agric. 

### Systems 29:233-246. Greene, D.K, KD. Johnson, J.H. Cherney, andJJ. Volenec. 1989. Feasibilityofinterseeding sorghum into cool-season grass 

### sod.Agron. Abst. p. 132. Greene, D.K, KD. Johnson, J.H. Cherney, andJ.J Volenec. 1990. Biomass yield and chemical composition ofdoublecropped sorghum andrye. 

### In Proc. Forage and Grassland Con[., 6-9 June, 1990, Blacksburg, VA, pp. 324-328.

### •



# ..

.. 1. 2-11. 12-21. 22. 23. 24-33. 34.

57. 58. 59. 60. 61. 62. 63. 64-73. 74. 75. 76. 77. 78. 79. 80-81. 82. 83. 84-88. 89. 90. 91-95. 96. 97. R. S. Carlsmith J. H. Cushman J. W. Johnston J. W. Ranney 

### G. A Tuskan A F. Turhollow R. I. Van Hook 

### 33 ORNL/Sub/85-27412/5&Pl INTERNAL DIS1RIBUTION 35. 36. 37-51. 52-53. 54. 

### 55. 56. 

### L L Wright Central Research Library ESD Library Laboratory Records Dept. Laboratory Records, RC ORNL Patent Office ORNL Y-12 Technical Library EX1ERNAL DIS1RIBUTION C. S. Accola, 1496 Agronomy Hall, Iowa State University, Ames, lA 50011 I. C. Anderson, Dept. of Agronomy, Iowa State University, Ames, lA 50011 P. C. Badger, Southeastern Regional Biomass Energy Program, National Fertilizer and Environmental Research Center, Tennessee Valley Authority, CEB IS 742-M, Muscle Shoals, AL 35660-1010 J. Berning, Electric Power Research Institute, 3412 Hillview Ave., P. 0. Box 10412, Palo Alto, CA 94303 D. Bransby, Dept. ofAgronomy and Soils, Auburn University, Auburn University, AL 36849 J. L. Butler, Coastal Plain Experiment Station, Agricultural Research Service, P. 0. Box 748, Tifton, GA 31793 D. R. Buxton, Dept. of Agronomy, Iowa State University, Ames, lA 50011 J. H. Cherney, Department of Agronomy, Purdue University, West Lafayette, IN 47907 M. Collins, University of Kentucky, N-122 Agricultural Sciences Bldg.-N, Lexington, KY 40546-0091 J. S. Cundiff, Department of Agricultural Engineering, Virginia Tech, Blacksburg, VA 24061 W. 

### Lee Daniels, Department ofAgronomy, Virginia Tech, Blacksburg, VA 24061 C. L Dobbins, Dept. ofAgricultural Economics, Purdue University, W. Lafayette, IN 47907 B. C. English, Dept. of Agricultural Economics and Rural Sociology, P. 0. Box 1071, University ofTennessee, Knoxville, TN 37901-1071 D. 0. Erickson, Animal and Range Science Dept., North Dakota State University, Fargo, ND 58105 J. E. Ferrell, Biofuels Systems Division, Department of Energy, MS CE-341, Forrestal Building, 1000 Independence Avenue, S.W., Washington, DC 20585 G. W. Fick, Department of Agronomy, Cornell University, Ithaca, NY 14853 G. Grinnell, Office of Energy, U.S. Dept. ofAgriculture, Administration Building, Route 194E, 14th and Independence Ave., Washington, DC 20250..2600 D. K. Green, Dept. of Agronomy, Purdue University, W. Lafayette, IN 47907 T. L. Grove, Department ofAgronomy, Cornell University, Ithaca, NY 14853 K. D. Johnson, Dept. ofAgronomy, Purdue University, W. Lafayette, IN 47907 E. J. Kladiuko, Dept. of Agronomy, purdue University, W. Lafayete, IN 47907 F. J. Kuzel, Council of Great Lakes Governors, 310 S. Michigan Ave., lOth Floor, Chicago, IL 60604 D. J. Lathwell, Department ofAgronomy, Cornell University, Ithaca, NY 1485398. 99. 100. 101. 

### 102. 103. 104. 105. 106. 107. 108. 109. 

### 110-119. 120. 121. 122. 

### 123. 124-133. 34 

### J. Lowenberg-DeBoer, Dept. ofAgricultural Economics, Purdue University, W. Lafayette, IN 47907 A Mdafri, Dept. of Agricultural Economics, Purdue University, W. Lafayette, IN 47907 D. W. Meyer, Agronomy Department, North Dakota State University, SU Station, Fargo, ND 58105 D. 

### J. Parrish, Department of Agronomy, Virginia Tech, Blacksburg, VA 24061 P. V. Preckel, Dept. of Agricultural Economics, Purdue University, W. Lafayette, IN 47907 M. W. Phillips, Dept. of Agronomy, Purdue University, W. Lafayette, IN 47907 N. Rader, Public Citizen, 215 Pennsylvania Ave, S.E., Washington, D.C. 20003 D. Rhinebolt, NWEA, 1730 N. Lynn St., Suite 610, Arlington, VA 22209 

### J. C. Roetheli, USDNSPPS, 14th and Independence Ave., S.W., Suite 342, Aerospace Bldg., Wshington, DC 20251-2200 D. Stucky, Dept. of Agricultural Economics, Purdue University, W. Lafayette, IN 47907 W. Tyner, Dept. of Agricultural Economics, Purdue University, W. Lafayette, IN 47907 D. H. Vaughan, Department of Agricultural Engineering, Virginia Tech, Blacksburg, VA 24061 

### J. J. Volonec, Dept. of Agronomy, Purdue University, W. Lafayette, IN 47907 W. Tolles, Applied Science Associates, Lee Highway, Fairfield, VA 24435 D. D. Wolf, Department ofAgronomy, Virginia Tech, Blacksburg, VA 24061 N. A Wright, Geophyta, Inc., 2685 C. 

### R. 254, Vickery, OH 43464 Office of Assistant Manager for Energy Research and Development, Oak Ridge Operations, P.O. Box 2001, Department of Energy, Oak Ridge, TN 37831-8600 Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831



### •