Table of Contents
Wright, N.A. 1990. Screening of herbaceous species for energy crops on wet
soils in Ohio. p. 263-267. In: J. Janick and J.E. Simon (eds.), Advances in
new crops. Timber Press, Portland, OR.
Screening of Herbaceous Species for Energy Crops on Wet Soils in Ohio*
- EXPERIMENTAL METHODS
- CROP ESTABLISHMENT
- Harvest Frequency
- Table 1
- Table 2
- Table 3
Utilization of lignocellulosic crops for energy is rooted in the need for the
United States to become less dependent on non-renewable sources of energy when
such commodities become scarce. With a limited supply of fossil fuels, it
becomes imperative to search for renewable energy sources. Such a source
exists in grass and legume herbage for direct combustion or possible conversion
to ethanol. This need was recognized by the U.S. Department of Energy (USDOE)
with the beginning of the Herbaceous Energy Crops Program (HECP). The
objective of the HECP is to screen herbaceous species under various crop
production management practices on marginal land.
The Office of Technology Assessment (1980) stated in Energy from Biological
Processes that grasses could contribute 29% of the potential bioenergy
supply with the use of existing technology. They also suggested key research
and development needs for utilization of energy crops. One such need was the
selection of the most promising high yielding grasses and legumes, the first
objective of the USDOE (1978) Fuels from Biomass Program for agricultural and
nonwoody plants in 1978. Identification of potential species was initiated by
Benson et al. (1978) but screening species on marginal land remains to be
accomplished. For example, selection of high yielding grasses on very poorly
drained land has not been explored. Marginal land utilization for energy,
crops is in accordance with views that biomass species should be energy
conserving by requiring little fertilizer, thriving on poor soil, and
tolerating both wet and dry soils. The problem is that marginal soils often
have many, production limitations. Growing cost effective energy crops on such
soils will require exact matching of species, management levels, and soil
Bungay (1981) pointed out the costliness of getting high productivity on
marginal land where ",water is the yield limiting factor. Crops selection must
be geared also toward tolerance to wet, poorly drained soils. Of the nine
possible forage grasses mentioned by Wedin and Helsel (1980) as suited for the
north central region of the United States, only four have characteristics that
show promise for maintaining prolonged productivity on wet, poorly drained
soils. Birdsfoot trefoil (Lotus corniculatus L.) will grow on poorly
drained, infertile soil (Seaney, 1973) and tall fescue (Festuca
arundinacea Schreb.) shows good tolerance to poorly drained soils vet is
also drought tolerant (Buckner and Cowan 1973). Probably the most flood
tolerant grass currently in use is reed canarygrass (Phalaris
arundinacea L.); tolerance to spring flooding of 49 or more days has been
reported for mature plants (Martin and Heath 1973). Establishment practices
for low fertility soils have been described by Kroth et al. (1976). Perennials
with these characteristics are the most likely to survive on very poorly
drained soils of low fertility. Fertilization along with weed control will be
the most important and expensive management inputs for energy crop production.
The objective of this project is to screen herbaceous species that appear
promising for energy uses on soils which are marginal due to wetness.
Three sites were selected to screen ten crops under two levels of weed control
management and two fertility levels in a randomized complete block design with
three replications of each treatment combination. Species being screened
include alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus
corniculatus L.), timothy, (Phleum pratense L.), tall fescue
(Festuca arundinacea Schreb.), reed canarygrass (Phalaris
arundinacea L.) switchgrass (Panicum virgatum L.), rye (Secale
cereale L.), sorghum x sudangrass(Sorghum bicolor L. Moench),and two
forage sorghum (Sorghum bicolor L. Moench) varieties. Rye and sorghum x
sudangrass are used in a double cropping system. All three sites are located
on Mollic Haplaquept silty clays with varying degrees of internal drainage,
slope, and initial fertility. Site one contains subsurface drainage file,
adequate soil pH, high fertility, and 0-2% slope. Site two has no tile,
adequate soil pH and fertility, and 2-6% slope. Site three has no file, low,
soil pH, low available phosphorus, and 0-2% slope. These three sites span the
range from best to worst for a Toledo silty, clay of lacustrine origin.
Management treatments for all sites include two weed control and two fertility
levels. Level zero weed control involves no control measures. Level one weed
control consists of chemical control used in normal production of these
species. Level zero fertility represents adequate fertilizer additions to
maintain initial soil nutrient levels and allowing nitrogen deficiency symptoms
to develop just before harvest. Level one fertility represents an excess of
fertilizer additions to eliminate fertility as a yield limiting factor during
screening. All species at all sites are harvested once at the end of each
growing season. An additional treatment at site one involves harvest of
certain species twice each season.
The difficult nature of crop production on marginal soil was fully expressed
during perennial establishment by conventional tillage. Three failed attempts
at establishment of smooth bromegrass at all sites resulted in its elimination
from the species fist. Tall fescue at site two and reed canarygrass at site
three were deleted after three seeding failures. Tall fescue at site three was
established on the third attempt. All sorghum species during each year
exhibited the same problem but not to the extent of the perennials. The
difficulty in establishment was due to soil crusting and later by winter freeze
and thaw upheaval of young plants seeded during late summer. Soil crusting is
one of the hazards of conventional tillage establishment of crops on silty
clays. The necessity of pulverizing the soil for proper soil to seed contact
always leaves the soil vulnerable to crusting. A no-till seeding study is
underway to determine if these difficulties can be reduced by the presence of a
residue mulch. Also, fall and spring seeding will be compared to determine if
winter survival of seedlings can be increased by spring establishment.
Yield differences in 1986 due to species were significant at all three sites
(Table 1). The two leaders in dry matter production were forage sorghum at
14-22 t/ha and the rye and sorghum x sudangrass double crop system at 22-24
t/ha. Switchgrass was the third highest producer with only 4-6 t/ha.
Increased fertilization resulted in overall yield increases at all sites. At
site one, yield differences between the high and low fertility levels was
solely a response to nitrogen for the grasses. The two legumes (alfalfa and
birdsfoot trefoil) did not respond to nitrogen. A 2.0 t/ha forage sorghum
yield response to higher fertility at site two was due to additions of
nitrogen, phosphorus, and potassium. Lime, nitrogen, phosphorus, and potassium
additions were responsible for 1.6-5.8 t/ha yield increases for timothy,
switchgrass, forage sorghum, and rye-sorghum x sudangrass at site three. Weed
control did not increase biomass yields in the first year with the exception of
metolachlor to sorghum species where yield increases of 4.1-11.9 t/ha resulted.
Dry matter yields for 1987 were higher for most of the perennials and similar
for the annuals compared to 1986 (Table 2). Two forage sorghum cultivars,
yielded 18-26 t/ha, and the rye-sorghum x sudangrass double crop system,
yielded 19-24 t/ha. Significant yield responses to increased fertility were
detected in the second year for most species at one or more sites. Benefits of
weed control were more apparent in year two. For example, application of
atrazine doubled yield of switchgrass from 3 to 6 t/ha.
Table 3 is a breakdown of site one yields according to the number of cuttings
removed per season in 1987. Both alfalfa and timothy under a one harvest per
year plan suffered loss of dry matter when compared to the first of two
harvests under the two cut system. Timothy dry matter losses were due to loss
of the seed head upon drying and some lower leaf decay. Tall fescue, reed
canarygrass, switchgrass, and birdsfoot trefoil all exhibited higher yields for
the first harvest under both systems. These species were able to continue
accumulation of dry matter even after seed maturity and did not lose as many
leaves from decay as alfalfa and timothy. The only species to yield more under
a one harvest system than the sum of two cuttings was birdsfoot trefoil.
Whether increased yields from two harvests per season are enough to merit the
expense of an extra trip over the field remains to be determined. Since forage
quality in terms of livestock use is not a factor, it may be more economical to
harvest only once at the end of a growing season.
Two years of data concerning the screening of herbaceous species for energy
crops has led to some preliminary suggestions for the best species and
management for lignocellulose production on wet, marginal land. Establishment
has proven very difficult on the silty clay soils in this study. Problems of
establishment must be considered when performing any economic analysis. A new
study underway will compare conventional tillage to no-tillage establishment
methods on the same soil type used for yield screening. No-till methods of
seeding may increase the chance of successful establishment and reduce costs of
production. Annual species showed a yield response to weed control additions.
For all grass species, higher fertility resulted in higher yield. Additional
yield was also achieved by harvesting twice each season compared to one harvest
at the end of the growing season. An economic evaluation will determine if the
additional dry matter gained from two harvests offsets the additional cost of
the second trip over the field. These preliminary findings indicate that the
most desirable perennials for energy crops on seasonally wet soils in Ohio
would be reed canarygrass and birdsfoot trefoil, both yielding 6-7 t/ha.
Annuals with the most promise include forage sorghum and a rye-sorghum
sudangrass doublecropping system, yielding 18-24 t/ha.
- Benson, W.R., A. Allen, R. Athey, A. McElroy, M. Davis, and M. Bennett. 1978.
Systems study of fuels from grains and grasses, phase I, final report.
ALO/3729-1. National T-d R.F. Barnes (eds.) Forages. Iowa State Univ. Press.
- Bungay H.R. 1981. Energy, the biomass options. Wiley. New York.
- Kroth, E.M., L. Meinke, and R.F. Dudley. 1976. Establishing reed canarygrass on
low fertility soil. Agron. 68:791-794.
- Marten, G.C. and M.E. Heath. 1973. Reed canarygrass. In: M.E. Heath, D.S.
- Metcalfe, and R.F. Barnes (eds.). Forages. Iowa State Univ. Press. Ames.
- Office of Technology Assessment. 1980. Energy from biological processes:
Technical and policy options. Westview Press. Boulder, CO.
- Seaney, R.R. 1973. Birdsfoot trefoil. In: M.E. Heath, D.S. Metcalfe, and R.F.
Barnes (eds.). Forages. Iowa State Univ. Press. Ames.
- U.S. Department of Energy. 1978. Fuels from biomass program summary. U.S.
Government Printing Office. Washington, DC.
- Wedin, W.F. and Z. Helsel. 1980. Plant species for biomass production on
marginal sites. I: Forage grasses and legumes. In: J.S. Robinson (ed.) Fuels
from biomass: Technology and feasibility. Noyes Data Corp. Park Ridge, New
*This research is supported by the United States Department of Energy.
Biofuels and Municipal Waste Technology Division Herbaceous Energy, Crops
Program, through subcontract # 15X-27114V between Martin Marietta Energy
Systems, Inc. and Geophyta.
Table 1. Yields under one harvest per season management in 1986.
|Dry matter yield (t/ha)|
|Weed control||Fertility level|
|Site and species||Overall||Without||With ||Low||High|
|Rye + Sorghum x Sudan||23.6||24.1||23.0||22.6||24.6|
|LSD (0.05)||0.6||- 1.0 -||- 1.0 -|
|Rye + Sorghum x Sudan||22.2||21.9||22.5||21.5||22.8|
|LSD (0.05)||1.1||- 1.6 -||- 1.6 -|
|Rye + Sorghum x Sudan||22.2||20.2||24.3||20.3||24.2|
|LSD (0.05)||0.9||- 1.3 -||- 1.3 -|
Table 2. Yields under one harvest per season management in 1987
|Dry matter yield (t/ha)|
|Weed control||Fertility level|
|Site and species||Overall||Without||With ||Low||High|
|Site # 1:|
|Alfalfa ||4.2 ||4.2 ||4.2 ||4.2 ||4.2|
|Timothy ||4.7 ||5.1 ||4.4 ||4.3 ||5.2|
|Switchgrass ||4.7 ||3.0 ||6.4 ||4.1 ||5.4|
|Tall fescue ||5.1 ||4.7 ||5.4 ||4.4 ||5.7|
|Birdsfoot trefoil ||6.7 ||6.6 ||6.7 ||7.0 ||6.4|
|Reed canarygrass ||7.1 ||7.3 ||7.0 ||5.7 ||8.6|
|Forage sorghum-FS25E ||17.9 ||15.5 ||20.2 ||15.6 ||20.1|
|Forage sorghum-S214 ||20.7 ||20.5 ||21.0 ||20.6 ||20.9|
|Rye + Sorghum x Sudan ||24.3 ||24.2 ||24.4 ||20.8 ||27.8|
|LSD (0.05) ||1.3 ||- 2.0 - ||- 2.0 -|
|Alfalfa ||3.8 ||3.8 ||3.7 ||3.8 ||3.8|
|Timothy ||3.8 ||4.2 ||3.5 ||3.2 ||4.5|
|Switchgrass ||4.1 ||2.3 ||5.8 ||3.4 ||4.7|
|Birdsfoot trefoil ||6.7 ||6.4 ||6.9 ||6.6 ||6.7|
|Reed canarygrass ||6.0 ||5.9 ||6.2 ||5.4 ||6.6|
|Forage sorghum-FS25E ||21.0 ||18.9 ||23.1 ||22.0 ||20.0|
|Forage sorghum-S214 ||20.2 ||19.8 ||20.5 ||18.6 ||21.8|
|Rye + Sorghum x Sudan ||21.0 ||20.9 ||21.1 ||18.3 ||23.7|
|LSD (0.05) ||1.6 ||- 1.2 - ||- 1.2 -|
|Alfalfa ||3.8 ||3.7 ||3.9 ||3.8 ||3.9|
|Timothy ||3.2 ||3.6 ||2.9 ||2.8 ||3.6|
|Switchgrass ||3.0 ||1.9 ||4.1 ||2.5 ||3.5|
|Tall fescue ||3.6 ||3.6 ||3.5 ||2.8 ||4.3|
|Birdsfoot trefoil ||5.9 ||5.5 ||6.3 ||5.2 ||6.6|
|Forage sorghum-FS25E ||17.1 ||15.3 ||18.8 ||19.0 ||15.0|
|Forage sorghum-S214 ||25.7 ||28.8 ||22.7 ||24.3 ||27.1|
|Rye + Sorghum x Sudan ||19.0 ||18.1 ||19.9 ||17.5 ||20.5|
|LSD (0.05) ||1.4 ||- 1.0 - ||- 1.0 -|
Table 3. Yields separated by harvest frequency at site one in 1987.
| ||Dry matter yield (t/ha)|
|Species ||1 ||2|
|Alfalfa || ||4.6|
| || ||2.7|
| ||4.2 ||7.3|
|Timothy || ||5.7|
| || ||1.5|
| ||4.7 ||7.2|
|Switchgrass || ||3.9|
| || ||3.0|
| ||4.7 ||6.9|
|Tall fescue || ||4.7|
| || ||3.0|
| ||5.1 ||7.7|
|Birdsfoot trefoil || ||4.3|
| || ||2.0|
| ||6.7 ||6.3|
|Reed canarygrass || ||6.1|
| || ||3.2|
| ||7.1 ||9.3|
|Rye ||3.5 ||3.5|
|Sorghum x sudangrass || ||5.1|
|Sorghum x sudangrass ||20.8 ||18.2|
| ||24.3 ||26.8|
|LSD (0.05)-Totals ||1.3 ||1.3|
Last update March 6, 1997