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PRODUCTION PAPERS

Optimum Planting Procedures for Eastern Gamagrass

^a Dep. of Agron., Iowa State Univ., Ames, IA 5001
^b Dep. of Stat., Iowa State Univ., Ames, IA 5001

^* Corresponding author (lgibson{at}iastate.edu)

Received for publication August 30, 2002.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Eastern gamagrass (Tripsacum dactyloides L.) is a warm-season, perennial bunch grass with great potential for use in grazing, cut forage, and conservation systems. Current recommendations for planting eastern gamagrass during the winter (November to February) are suitable for many areas but are inadequate in locales were the ground is frozen during most of this period. The objectives of this study were to determine the best combinations of planting date, planting depth, and seed stratification for eastern gamagrass in the northern range of its adaptation. Unstratified and stratified gamagrass seed was planted in mid-August, late October–early November, mid-April, mid-May, and mid-June at 2.5- and 5.0-cm planting depths over two growing seasons. Planting in the late summer and fall resulted in better stand establishment than planting in the spring and early summer. The net seedling survival from plantings in April and May was 39 and 48% less than from summer and fall plantings of unstratified seed in 1999–2000 and 2000–2001, respectively. Seed stratification was beneficial to April plantings in only one year of the study and did not improve May or June plantings. At most planting dates, depth had little influence on final stand. Full stands contained at least one plant per 25 cm of row. Plantings producing stands above this level were the August, November, and June plantings in both years and the April planting of stratified seed in the first study year. While the June plantings resulted in adequate final stand numbers, stand establishment was delayed for more than 10 mo because most of the plants did not emerge until the following spring.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
EASTERN GAMAGRASS is a warm-season, perennial bunch grass found growing naturally from the northeastern and north-central United States and south into Mexico, Central America, the Caribbean, and into Bolivia and Paraguay in South America (Newell and de Wet, 1974). It has agronomic (Brejda et al., 1994; Dickerson and Van Der Grinten, 1990; Fine et al., 1990; Joost and Roberts, 1996) and quality characteristics (Burns et al., 1992; Fine et al., 1990; Horner et al., 1985) that make it excellent forage for grazing or mechanical harvest. It also has a number of conservation uses, including grass hedges for reducing runoff and erosion in row-crop fields, use in riparian zones, buffer strips, and conservation reserve program (CRP) acres in low-lying or wetter locations (Dewald et al., 1996).

The potential of eastern gamagrass for pastures, cut forage, and conservation has been well documented, but there are several factors currently limiting its adoption. Poor stand establishment resulting from seed dormancy remains one of the greatest factors. Seed viability is generally high, but laboratory germination of dry, intact, and cupulated seed is often less than 10%. Cold, moist stratification has been recommended and adopted as practice for breaking eastern gamagrass seed dormancy (Ahring and Frank, 1968), but there are several associated problems. Seed must be stratified for 6 wk before planting (by either the seed supplier or the person planting it). Stratification requires appropriate facilities, and the seed must be kept cold during shipping. Once the seed is stratified, it must be stored cold to prevent heating and desiccation. Moist seed also complicates the planting operation because it does not flow through a drill or planter as freely as dry seed.

Many groups including the USDA-NRCS (1986, 2002), some state extension services (Ohlenbusch and Kilgore, 1999; Roberts 1991), and seed producers (Anonymous, 1999b) have developed planting guidelines for eastern gamagrass. Winter plantings may be one of the more successful practices for establishing eastern gamagrass because winter conditions trigger natural processes that break seed dormancy (Ahring and Frank, 1968; Anderson, 1985). Many of these recommendations appear to be based on experiential knowledge and studies of cold, moist stratification on germination and emergence.

Mueller et al. (2000) reported significantly greater stand establishment of eastern gamagrass in North Carolina with November through February plantings than March and April plantings. These results provide satisfactory recommendations for planting of eastern gamagrass in areas with moderate winter temperatures. However, they are not sufficient for northern areas of eastern gamagrass adaptation because soils are typically frozen during the November to February period. In addition, production of full-season summer annual crops in much of the U.S. Corn Belt often limits the amount of time available for establishment of forage and conservation plantings in the spring and fall months. The objectives of this study were to determine the best procedures and provide recommendations for planting eastern gamagrass in the northern range of its adaptation.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
A 2-yr field experiment was conducted beginning in August 1999 at the Iowa State University Sorenson Farm near Ames, IA (41°59' N, 93°55' W), on a Canisteo silty clay loam [fine-loamy, mixed (calcareous), mesic Typic Haplaquoll]. Eastern gamagrass was seeded in a randomized complete block design with four replicates in a factorial combination of five planting dates, two planting depths, and two seed treatments. The planting dates were 16 Aug. 1999, 1 Nov. 1999, 14 Apr. 2000, 15 May 2000, and 16 June 2000 for Year 1 and 15 Aug. 2000, 31 Oct. 2000, 17 Apr. 2001, 15 May 2001, and 15 June 2001 for Year 2 of the study. The two planting depths were 2.5 and 5.1 cm, and the two seed treatments included cold-moist stratification and no stratification.

The experimental areas were previously in a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation, with corn in 1998 and soybean in 1997. The experimental areas were soil-tested on 19 Nov. 1998 and contained 30 mg kg^-1 P, 200 mg kg^-1 K, 58.5 g kg^-1 organic matter, and a buffer pH of 6.6. They were limed on 2 Dec. 1998 to bring the soil pH to 6.8. Nineteen ninety-nine was a fallow year in preparation for the experiments. Field preparation included two double-disking operations, followed by field cultivation. A John Deere Model 71 Flexi-Unit planter with double-disc openers (Deere & Co., Moline, IL) was used to plant. Depth bands were used to precisely control the planting depth. The seed was planted in rows spaced at 76.2 cm at a rate of 15.7 seeds m^-1 row in plots that were four rows wide and 6.1 m long. The plots received no fertilization during the experiments. AAtrex 4L {atrazine[6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine]} (Syngenta Crop Protection, Greensboro, NC) was surface-applied for weed control at 2.05 kg ha^-1 a.i. on 5 May 2000 and 10 May 2001. The plots were hand-weeded as needed throughout the duration of the experiment.

Seed of ‘Pete’ eastern gamagrass used for this experiment was purchased from Gamagrass Seed Co., Falls City, NE. Seed planted in Year 1 was harvested in 1998, and seed planted in Year 2 was harvested in 1999. Seed (0.7 kg) for the cold, moist stratification treatment was placed in a cloth bag, soaked in 1 L of 2.5 g kg^-1 thiram [bis(dimethylthiocarbamoyl) disulfide] solution, drained after 24 h, and placed in cold storage for 6 wk at 4°C and 40% relative humidity. Unstratified seed was continuously stored dry in 4°C and 40% relative humidity until planting.

A standard germination test, with three replicates, was begun on both stratified and unstratified seed on the day of each planting. Fifty seeds were placed in 13- by 13- by 3.5-cm covered containers containing two layers of Anchor Steel Blue seed germination paper (Anchor Paper Co., St. Paul, MN) moistened with distilled water. The tests were performed at alternating temperature of 20 and 30°C (Ahring and Frank, 1968) with light supplied by four 40-W cool-white fluorescent lights vertically oriented on both the left and right sides of the germinator and 30°C for 8 h daily. Germination counts were made every 7 d for 28 d. Seeds were considered germinated if the coleoptile exceeded the seed in length and the seedling was normal according to the seedling evaluation criteria of AOSA for comparable grasses (AOSA, 1992). Normal seedlings were removed as they were counted. Water was added to each germination box as needed to maintain optimum moisture levels. After 28 d of incubation, ungerminated seeds were examined by tetrazolium (TZ) tests (AOSA, 1998) and classified as dormant or dead.

In the field studies, total live seedlings, newly emerged seedlings, and newly dead seedlings were counted weekly during the growing season. A seedling was considered emerged when it was about 3.0 cm in height and visually discernable from other grass seedlings. Seedlings were considered dead when they wilted, became completely chlorotic, and showed no sign of recovery. The total number of live seedlings at 1 yr after planting was converted to a percentage of the total number of seeds planted per plot and reported as net seedling survival. Accumulated emergence over the first year after planting was calculated by adding each week's newly emerged seedlings to the accumulated emergence for the previous week and converting to a percentage of the total of number of seeds planted per plot. Seedling mortality was calculated by dividing the total number of seedlings that died in the first year after planting by the total number of plants emerging in each plot during this period and converting to a percentage. Because of considerable emergence in the second year following planting, net seedling survival and mortality counts were taken on 28 May and 11 June 2002 for the 17 Apr. 2000 and 15 May 2000 plantings, respectively. Precipitation (Fig. 1) and temperature (Fig. 2) were monitored at the Iowa State University Agronomy–Agricultural and Biosystems Engineering Farm approximately 2 km northwest of the experiment site.

View larger version (33K): [in this window] [in a new window]   Fig. 1. Monthly average precipitation from August 1999 to June 2002 for the Iowa State University Agronomy–Agricultural and Biosystems Engineering Farm near Ames, IA.

View larger version (51K): [in this window] [in a new window]   Fig. 2. Monthly mean temperature from August 1999 to June 2002 for the Iowa State University Agronomy–Agricultural and Biosystems Engineering Farm near Ames, IA.

Statistical analysis of emergence rate was performed using tests for equality of survival curves (Hosmer and Lemeshow, 1999). Replicates of each treatment (combination of planting date, planting depth, and seed treatment) were summed to define a cohort of individuals. To compare rates of emergence between treatments, the weekly counts of newly emerged seedlings were used to compute the time from planting to emergence for every ungerminated seed. The time to emergence for seeds that did not germinate was a censored value (an unknown value longer than the length of the study) (Dixon and Newman, 1991). The null hypothesis that treatments have the same emergence curves was tested using the nonparametric log-rank test (Hosmer and Lemeshow, 1999) computed using the LIFETEST procedure in SAS.

	RESULTS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Net Seedling Survival
Analysis of variance revealed that net seedling survival was influenced by interactions of planting date, planting depth, and stratification treatments (Table 1). The planting date x planting depth, planting date x stratification, and planting date x planting depth x stratification interactions were significant in 1999–2000. The main effects of planting date were also significant. In 2000–2001, the planting date and stratification main effects and planting date x depth and planting date x stratification interactions were significant for net survival. Interactions in both seasons indicated that the combined effects of planting date, depth, and stratification influenced the success of the eastern gamagrass plantings.

View larger version (50K): [in this window] [in a new window]   Fig. 3. The effects of combinations of planting depth, seed stratification, and planting date on net survival of eastern gamagrass at 1 yr after planting. Because of considerable emergence in the second year after planting, counts for the 17 April and 15 May 2002 plantings were extended to 28 May and 11 June 2002, respectively.

Although the planting date x depth interaction for net seedling survival was significant in both study years, very few differences in net seedling survival between the 2.5- and 5.0-cm planting depths were found when the effects of planting depth were analyzed at each planting date. The shallower depth resulted in greater net seedling survival in the 16 June 2000 and 15 Aug. 2000 plantings but less net seedling survival in the 1 Nov. 1999 planting (Fig. 3).

Accumulated Seedling Emergence and Seedling Mortality
The final net seedling survival (total number of live plants at 1 yr after planting) was a function of the accumulated seedling emergence (Fig. 4 and 5) and seedling loss through mortality (Fig. 6). Accumulated emergence was monitored with weekly stand counts after planting. When the emergence curves were statistically analyzed for each planting date using tests for equality of survival curves (Hosmer and Lemeshow, 1999), differences among treatments were significant at P > 0.001, except 17 Apr. 2001, which was not significant.

View larger version (26K): [in this window] [in a new window]   Fig. 4. The effects of planting date and seed stratification combinations on mortality of eastern gamagrass seedlings in the year after planting. Each bar represents the average of seedlings for planting depths of 2.5 and 5.0 cm. Because of considerable emergence in the second year after planting, counts for the 17 April and 15 May 2002 plantings were extended to 28 May and 11 June 2002, respectively.

View larger version (32K): [in this window] [in a new window]   Fig. 5. Emergence patterns of eastern gamagrass planted in the fall at various combinations of planting date, depth, and seed stratification.

View larger version (36K): [in this window] [in a new window]   Fig. 6. Emergence patterns of eastern gamagrass planted in the spring at various combinations of planting date, depth, and seed stratification.

Tests for equality of survival curves were made for the emergence curves of the two stratification treatments at each planting date and depth combination. For 1999–2000, the curves were statistically different for all of the planting date and depth combinations except the 2.5- and 5.0-cm depths planted on 16 June (Fig. 4 and 5). In the 16 August planting, emergence from stratified seed was greater than unstratified seed in the weeks immediately after planting. However, there were greater amounts of emergence of unstratified seed in the following spring. Emergence from the 1 November planting did not begin until the following spring, and unstratified seed produced greater emergence than stratified seed. Emergence in the planting season was greater for stratified seed in the 14 April and 15 May plantings. Great amounts of emergence from the unstratified seed in the spring following planting resulted in similar accumulated emergence at 1 yr after planting in the stratified and unstratified seed planted on 15 May.

Accumulated emergence was greater at 5.0 than 2.5 cm for the 1 November stratified and unstratified plantings and the 14 April unstratified plantings. In contrast, emergence was greater at 2.5 than 5.0 cm for the 16 June plantings of stratified and unstratified seed.

Main effects of planting date and stratification treatment on seedling mortality in the first year after planting were great in 1999–2000 (Table 1). In addition, the planting date x stratification interaction was significant. Seedling mortality was above 40% in the 16 August and 1 November plantings of both stratified and unstratified seed and the 14 April planting of stratified seed (Fig. 6). It was below 30% in the 14 April planting of unstratified seed and the 15 May and 16 June plantings of both stratified and unstratified seed. Seedlings from stratified seed had increased mortality compared with unstratified seed for 16 August, 14 April, and 16 June plantings but not the 1 November and 15 May plantings.

The relative contributions of accumulated emergence and seedling mortality to net seedling survival of the 1999–2000 plantings varied by planting date. Net seedling survival for the 16 August planting was greater for unstratified than stratified seed because emergence was greater and mortality was less for the unstratified seed. In the 1 November planting of unstratified seed, mortality was similar for the two planting depths, but emergence was less at 2.5 than 5.0 cm. Accumulated emergence and seedling mortality were similar for the 2.5- and 5.0-cm stratified plantings on 1 November. Net seedling survival for the 14 April planting of stratified seed was more than double that of unstratified seed because emergence was more than three times greater for the stratified seed. However, greater seedling mortality in the stratified seed somewhat diminished the emergence advantage. For the 15 May planting, net seedling survival, accumulated emergence, and mortality were similar in all of the stratification and planting depth combinations. The 2.5-cm unstratified planting had the greatest net seedling survival of the 16 June plantings. It had greater amounts of emergence than the other three plantings and less mortality than the 2.5- and 5.0-cm stratified plantings.

In 2000–2001, accumulated emergence at 1 yr after planting was 41% for unstratified seed compared with 36% for stratified seed when averaged across the five planting dates. There were no significant effects for planting date or the planting date x stratification interaction.

Emergence curves for unstratified and stratified seeds were statistically different in all planting date and depth combinations except 5.0 cm planted on 15 August and 2.5 and 5.0 cm planted on 17 April. Emergence in the spring following planting was greater for the unstratified than stratified seed in the 15 August planting at 2.5 cm and 31 October plantings at both depths. For the 15 May and 15 June plantings, the emergence during the season that the seed was planted was greater for stratified than the unstratified seed. Ultimately, the unstratified seed produced greater accumulated emergence at 1 yr after planting in the 15 May planting because a greater number of seedlings emerged from the unstratified seed in the spring following planting. Similarly, emergence in the second season from unstratified seed resulted in similar amounts of accumulated emergence at 1 yr after planting for the stratified and unstratified seed planted on 15 June. The emergence curves for planting depth were different for stratified seed planted on 15 August and unstratified seed planted on 15 August and 31 October. In all three of these situations, the 2.5-cm planting depth resulted in greater emergence.

Because planting date did not influence accumulated emergence at 1 yr after planting, seedling mortality was the major determinate of differences in net seedling survival among planting dates in 2000–2001. Seedling mortality was greater than 30% in the 17 April and 15 May plantings, about 22% in the 15 June planting, and below 5% in the August and November plantings. Stratified seed had greater seedling mortality than unstratified seed in the 17 April plantings but lower mortality in the 15 May planting. Seedling mortality of the 15 August, 31 October, and 15 June plantings was not affected by stratification. Planting depth had no effect on seedling mortality of any of the planting dates in 2000–2001.

In both study years, emergence generally began about 4 wk after the April plantings and 3 wk after planting in the other months. Plants appeared over a 6- to 9-wk period for the April, May, and June plantings. Most plantings had some seedling emergence in the second growing season after planting. These plants generally appeared over a 2- to 4-wk period beginning the first week of May. The exceptions were the August and November plantings in 1999, in which completion of spring emergence took about 8 wk. Rate of emergence was generally unaffected by planting depth but appeared to be more rapid with stratified than unstratified seed for the 16 Aug. 1999, 16 June 2000, and 17 Apr. 2001 plantings.

	DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 
Research by Mueller et al. (2000) and recommendations by the USDA-NRCS (2002) suggest that eastern gamagrass be planted from November to February. These recommendations are appropriate for areas with moderate winter temperatures but are not well suited for the northern area of eastern gamagrass adaptation because the soil is typically frozen during this period. The results of our study demonstrated that the most successful stands in our northern location were generally achieved by planting unstratified eastern gamagrass in mid-August and late October–early November. Successful plantings at both of these dates suggested that the period between them was suitable for planting eastern gamagrass.

We did have one situation were fall planting of unstratified seed was ineffective. The low emergence in 2.5-cm plantings made on 1 Nov. 1999 likely resulted from dry, windy weather conditions the following spring when seeds began germinating and plants were first emerging. The warm winds dried out the topsoil and resulted in considerable soil movement in the plots. The resulting wind erosion problems could have been lessened by no-till planting methods or inclusion of a cover crop. Because summer and fall were ideal times for planting eastern gamagrass, further studies are needed to develop a planting system for this period that protects against soil erosion. These results also suggest that fall plantings of eastern gamagrass should be deeper than 2.5 cm to ensure that dry spring conditions do not adversely affect seedling emergence.

The poorest net seedling survival was generally obtained from April and May plantings although April plantings of stratified seed produced high net seedling survival in one of the two study years. The net seedling survival from April and May plantings averaged 39 and 48% less than from the summer and fall plantings of unstratified seed in 1999–2000 and 2000–2001, respectively. In addition, the mortality from the April and May plantings could be as high or higher than that from summer and fall plantings. Although June plantings had a high net survival, most of the plants did not appear until the second growing season after planting. This left the soil exposed to erosion and weed infestation for more than 10 mo.

The summer and fall plantings of unstratified seed most closely mimicked natural conditions in which seed was dispersed in late summer and seed dormancy was naturally broken by cold, wet soil conditions during late fall, winter, and early spring (Anderson, 1985). The final net seedling survival from summer and fall plantings was similar, but there was greater seedling mortality in the summer planting of stratified seed in the first year of the study. Some plants from the summer planting emerged in the fall, especially when soil moisture was good and stratified seed was planted. These plants were at risk of being killed by the first frost, extreme winter conditions, or poor field conditions in the spring. However, this risk did not appear great enough to negatively affect the overall success of the summer plantings.

Results from the seed stratification treatments suggest that moist prechilling of eastern gamagrass seed should only be recommended for early spring plantings. Stratification nearly doubled the net seedling survival of April plantings in 1999–2000 but had no effect on net survival of April plantings in 2000–2001. Stratification did not influence net seedling survival of May or June plantings in either study year.

Seed stratification was not effective at promoting immediate seedling emergence in June plantings or the 15 Aug. 2000 planting. This suggested that stratified seed was sensitive to dry soil conditions and warm temperatures. This conclusion is further supported by the greater fall emergence in stratified than unstratified seed planted on 16 Aug. 1999 during a period of considerable precipitation. Poor stand establishment of eastern gamagrass from prolonged dry soil conditions has also been reported by Mueller et al. (2000).

The greatest net seedling survival in 2000–2001, at 45 to 52%, was higher than the 38 to 44% obtained in 1999–2000. The poorest net seedling survival in both 1999–2000 and 2000–2001 was 18 to 24%. The reasons for greater net seedling survival in 2000–2001 are not entirely clear. The two seed lots used in this study differed in germination percentage of stratified seed and viability (Table 2). The seed harvested in 1998 (Pete 98) and planted in the first year of the study had greater germination when seed was stratified than the seed harvested in 1999 (Pete 99) and used for the second year of the study. The viability of Pete 98 was lower than that of Pete 99, and the germination of dry seed was similar in both seed lots. Within seed lots, there was no significant difference in viability between stratified and unstratified seed.

There are no previous reports on the success of planting eastern gamagrass in late summer. Our data suggested that planting unstratified eastern gamagrass seed in August was generally better than planting either stratified or unstratified seed in April and May. This information will be valuable for updating eastern gamagrass planting recommendations in the U.S. Corn Belt where producers generally view spring as the most appropriate time for planting and workloads are generally less in late summer than the spring and fall.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION REFERENCES

 

• Ahring, R.M., and H. Frank. 1968. Establishment of eastern gamagrass from seed and vegetative propagation. J. Range Manage. 21:27–30.
• Anderson, R.C. 1985. Aspects of the germination ecology and biomass production of eastern gamagrass (Tripsacum dactyloides L.). Bot. Gaz. 146:353–364.
• Anonymous. 1999b. The gamagrass grower's guide [Online]. Available at http://www.gamagrass.com/grwguide.htm (verified 2 Apr. 2003). Gamagrass Seed Co., Falls City, NE.
• AOSA. 1992. Seedling evaluation handbook. Contrib. no. 35:84-87. AOSA, Las Cruces, NM.
• AOSA. 1998. Rules for testing seeds. AOSA, Las Cruces, NM.
• Brejda, J.J., J.R. Brown, J.M. Asplund, T.E. Lorenz, J.L. Reid, and J. Henry. 1994. Eastern gamagrass silage fermentation characteristics and quality under different nitrogen rates. J. Prod. Agric. 7:477–482.
• Burns, J.C., D.S. Fisher, K.R. Pond, and D.H. Timothy. 1992. Diet characteristics, digesta kinetics, and dry matter intake of steers grazing eastern gamagrass. J. Anim. Sci. 70:1251–1261.[Abstract]
• Dewald, C.L., J. Henry, S. Bruckerhoff, J. Ritchie, S. Dabney, D. Shepherd, J. Douglas, and D. Wolf. 1996. Guidelines for establishing warm season grass hedges for erosion control. J. Soil Water Conserv. 51:16–20.
• Dickerson, J.A., and M. Van Der Grinten. 1990. Developing eastern gamagrass as a haylage crop for the northeast. p. 194–198. In Proc. Forage Grassl. Conf., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA. 6–9 June 1990. Am. Forage Grassl. Counc., Georgetown, TX.
• Dixon, P.M., and M.C. Newman. 1991. Analyzing toxicity data using statistical models for time-to-death: An introduction. p. 207–242. In M.C. Newman and A. Mclntosh (ed.) Metal ecotoxicology: Concepts and applications. Lewis Publ., Chelsea, MI.
• Fine, G.L., F.L. Barnett, K.L. Anderson, R.D. Lippert, and E.T. Jacobsen. 1990. Registration of ‘Pete’ eastern gamagrass. Crop Sci. 30:371–372.
• Horner, J.L., L.J. Bush, G.D. Adams, and C.M. Taliaferro. 1985. Comparative nutritional value of eastern gamagrass and alfalfa for dairy cows. J. Dairy Sci. 68(10):2615–2620.[Abstract/Free Full Text]
• Hosmer, D.W., Jr., and S. Lemeshow. 1999. Applied survival analysis. Wiley–Interscience, New York.
• Joost, R., and C.A. Roberts. 1996. Eastern gamagrass [Online]. Available at http://muextension.missouri.edu/xplor/agguides/crops/g04671.htm (verified 2 Apr. 2003). Agric. Publ. G4671. Dep. of Agron., Univ. of Missouri, Columbia.
• Mueller, J.P., T.S. Hall, J.F. Spears, and B.T. Penny. 2000. Winter establishment of eastern gamagrass in the southern Piedmont. Agron. J. 92:1184–1188.[Abstract/Free Full Text]
• Newell, C.A., and J.M.J. de Wet. 1974. Morphological and cytological variability in Tripsacum dactyloides. Am. J. Bot. 61:652–664.
• Ohlenbusch, P., and G. Kilgore. 1999. Forage facts: Eastern gamagrass. Kansas State Univ. Agric. Exp. and Coop. Ext. Serv., Manhattan, KS.
• Roberts, C. 1991. Eastern gamagrass establishment. Missouri Univ. Tech. Rep. Vol. 9, no. 2. Univ. of Missouri Ext., Columbia.
• SAS Institute. 1999. SAS/STAT user's guide. Version 8. SAS Inst., Cary, NC.
• [USDA-NRCS] U.S. Department of Agriculture–Natural Resources Conservation Service. 1986. Pasture and hayland planting. Eastern gamagrass: Establishment techniques and determination of seeding rate. USDA–SCS, Salina, KS.
• [USDA-NRCS] U.S. Department of Agriculture–Natural Resources Conservation Service. 2002. Eastern gamagrass—plant fact sheet. USDA-NRCS Plant Materials Progr., Washington, DC.

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This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Aberle, E. Z. Articles by Hintz, R. Search for Related Content PubMed Articles by Aberle, E. Z. Articles by Hintz, R. Agricola Articles by Aberle, E. Z. Articles by Hintz, R. Related Collections Forage Management Other Forage Crops Seed Establishment