ENERGY GARDEN CROPS

The following is
a list of the crops currently growing in the Sebastopol Energy Garden as well
as those selected for the 2008 growing season. The crops have been categorized
by the major anthropocentric functions they fulfill and the morphological plant
parts of use. By assessing the crops in this manor we can correlate them with
their appropriate zone within the garden. In addition to providing the common
names and functions of the selected crops, optimal planting conditions are
provided for annuals, and background information is provided for profile crops.

PROFILE CROPS

Profile Crops support
the goals of the Sebastopol Energy Garden by offering local means of energy
security, food production, soil improvement, and water conservation. These
crops are most often cultivated in Zone 2 of the property.

Energy Security: Crops that function as potential sources of
energy are those high in calories (carbohydrates and lipids) grown for human
consumption, biofuel production, and anaerobic digestion.

Food Production: Crops grown as
local sources of food are chosen as profile crops if they display stacked
functions, are area-and-weight-efficient crops, or are beneficial
non-conventional crops.

Soil Improvement: Crops which
improve the soil are those capable of accumulating large quantities of minerals
and producing large amounts of carbon. These crops provide the required materials
for onsite preparation of compost and mulch, as well as function biologically
in the improvement of the health of the soil.

Water Conservation: Crops grown
for the purpose of water conservation are those which require low amounts of
water or those which improve the quality of water by functioning as
hyperaccumulators of water contaminants.

The following is the background
information of selected profile crops. They are organized by function in the
same order as above.

Switchgrass: (Panicum
virgatum) is a perennial grass native to North America. Because it is
native, switchgrass is resistant to many pests and plant diseases as well as
being very tolerant of poor soils, flooding and drought. It is easily
germinated from seed, and capable of producing high yields with very low
applications of fertilizer. Switchgrass makes for a great energy crop because
it grows fast, capturing lots of solar energy and turning it into chemical
energy which it stores as cellulose. Switchgrass reaches its full yield
potential after the third year planted, producing approximately 6 to 8 tons per
acre; that is 500 gallons of ethanol per acre. At maturity, widely spaced
switchgrass plants can measure 20 inches in diameter at ground level.
Switchgrass has a huge, permanent root system that penetrates over 10 feet into
the soil, and weighs as much as the above-ground growth from one year. It also
has many fine, temporary roots. All these roots improve the soil by adding
organic matter, and by increasing soil water infiltration and nutrient-holding
capacity.

Miscanthus: (Miscanthus
x giganteus) is a tall perennial grass that has been evaluated in Europe
during the past 5-10 years as a new bioenergy crop. Like other energy crops,
the harvested stems of miscanthus may be used as fuel for production of heat
and electric power, or for conversion to other useful products such as ethanol.
Because the crop is a sterile hybrid it is established by planting pieces of
the root, called rhizomes, which develop into the mature plant. Miscanthus is
ready for harvest within 2 years and yields continue to improve until they
level off around the 5th or 6th year. Speculating from European data, under
typical agricultural practices over large areas, an average of about 3 tons per
acre dry weight may be expected at harvest time.

Miscanthus
exhibits:

Relatively high yields 8-15 t/ha (3-6 t/acre)
dry weight.

Low
moisture content (as little as 15-20%).

Annual harvests, providing a regular yearly
income for the grower.

Relatively good energy balance and
output/input ratio

Low
mineral content, which improves fuel quality.

Jerusalem Artichoke: (Helianthus
tuberosus L.) is an annual flowering plant native to North America.
It grows 1-3 meters tall with flowers similar to the sunflower but much smaller
(4-8cm in diameter). Jerusalem artichokes are grown throughout the temperate
world for their tubers, which are used as a root vegetable. The tubers are
gnarly and uneven, vaguely resembling ginger root, with a crisp texture when
raw. Unlike most tubers, but characteristic of members of Asteraceae (Sunflower
family to which it belongs), the tubers store the carbohydrate inulin instead
of starch. The inulin is isolated on the basis of its high solubility in hot
water; by boiling the tuber and allowing it to cool polysaccharides can be
extracted. Yields tend to vary with soil conditions, cultivar and season, but
fresh weights in excess of 100 tons per hectare have been recorded, which is
around 8 tons per hectare of sugar. For this reason, Jerusalem artichoke tubers
are an important source of energy.

Sugar Beet: (Beta
vulgaris L.), a member of the Chenopodiaceae family, is a biennial plant
whose root contains a high concentration of sucrose, accounting for 30% of the
world's sugar production. During its first growing season, it produces a large
(1–2 kg) storage root whose dry mass is 15–20% sucrose by weight. Sugar beets
have the potential to produce 30-40 tons of roots per hectare under
non-irrigated conditions and 50-70 tons per hectare with irrigation. The
research done by the Agronomic University of Bucharest in the South zone of
Romania has recorded ethanol production at 5,508 liter ethanol per hectare. The
sugar beet may become, in the future an important energy crop.

Soybean: (Glycine max)
is an annual legume (Fabaceae). It may grow prostrate, not growing higher than
20 cm (7.8 inches), or stiffly erect up to 2 meters (6.5 feet) in height.
Soybeans provide the principal oil being utilized for biodiesel in North
America. To produce soybean oil, the soybeans are cracked, adjusted for
moisture content, rolled into flakes and solvent-extracted with commercial
hexane. According to the U.S. Department of Agriculture's (USDA) Farm Service
Agency, one bushel of soybeans yields approximately 1.4 gallons of biodiesel.
Soybeans contain about 20% oil, so it takes almost 7.3 pounds of soybean oil to
produce a gallon of biodiesel. In addition soybeans enhance the nitrogen
content of the soil and provide the soil with many nutrients.

Dale Sorghum: (Sorghum
bicolor L.) is an annual tropical grass that is easily propagated from
seed. A prolific producer, averaging
about twelve feet in height at maturity; sorghum is a short rotation crop,
meaning that it can be harvested multiple times throughout the year. Sweet
sorghums have been selected for their high sugar content and are normally grown
for molasses production. Dale Sorghum is a drought resistant variety of sweet
sorghum that requires less intensive irrigation. It is an early maturing (115
day) variety with superior disease resistance to many older common varieties
and is well adapted for syrup production, which can be converted to methane or
ethanol. It produces on average 40 tons per hectare of cane, 25 tons per
hectare of juice, and provides a grain yield of 2-6 tons per hectare. It is
estimated that for each ton of cane yield 40 liters of ethanol can be produced,
that is 1600 liters of ethanol per hectare of Sorghum.

Peredovik Sunflower: (Helianthus
annuus) is an energy and protein rich annual that at maturity (12 weeks
after germination), reaches a height of 4 feet. Second only to soybeans,
sunflower oilseed varieties are the most important source of high-quality
vegetable oil in the world. This Russian cultivar produces small, black seeds
that yield more oil than most other sunflowers (approximately 952 liters of oil
per hectare). While typical sunflower seeds contain 25–35% oil, the peredovik
sunflower can contain up to 50% oil. According to the Duke handbook of Energy
Crops, a hundred kilograms of dry seed will yield about 40 kilograms of oil,
15–20 kilograms of hulls, and 40 kilograms of proteinaceous meal.

Rapeseed: (Brassica
napus) contains erucic acid, which is mildly toxic to humans in large
doses. The word "canola" is derived from "Canadian oil,
low acid;" it is a particular cultivar of Rapeseed developed
to produce low amounts of erucic acid. Rapeseed is the third leading source of
vegetable oil after soybean and oil palm, and the world's second leading source
of protein meal. The oil content runs 42.0–44.5%, and oil yields of more than 1
MT/ha are reported. Due to this high oil production per unit of land area
rapeseed oil is the preferred oil stock for biodiesel production in most of
Europe. The crop is particularly of interest because it not only produces
higher yields during the autumn growing period but the oil percentage of the
harvest is higher as well.

Flax: (Linum
usitatissimum L.) is an erect annual with slender stems that is
grown for its seed and fiber. It is not generally a crop that is spoken of in
relation to alternative fuel sources; however, there are groups looking into
the possibility of using the long tough stem fibers of oilseed flax as
feedstock for large scale burners. Flax seeds contain 20–30% protein, and are
the source of linseed oil. Flax straw has a per ton heating value similar to
soft coal that is much greater than other crop residues. Not only is the straw
cheaper than conventional fuels; it is also carbon neutral fuel; meaning that
the plant takes carbon from the air during the growing season to produce the
straw, reducing the amount of greenhouse gasses in the atmosphere. With seed
yields of 1000–4000 kilograms per hectare, and reported oil content of 34–37%,
flax has the potential to yield 1500 kilograms of oil per hectare.

Safflower: (Carthamus
tinctorius) is a member of Asteraceae; it is a thistle-like plant growing
30-150 cm tall with globular flower heads (capitula) of commonly, yellow,
orange or red flowers. . Safflower is grown exclusively for its oil which is
high in essential unsaturated fatty acids. Oil yields approach 50%, leaving a
meal with 21% protein, 35% fiber, and 1-3% fat, a great source of nutrients for
feedstock. According to Khoshoo (1982), the BTU value per gallon of safflower
oil is 130,730. The crops viscocity of 32.7 has been described in concern;
however, tractors were run on 100% safflower oil for over 90 hours to cut hay
and cultivate in Australia, and diesel engines fueled with safflower oil were
run more than 700 hours in Idaho with no obvious difference ascribed. It has
been reported that for every 212-262 gallons of extractable oil harvested per
hectare 25 gallons of fuel is required. (Khoshoo, 1982). High oleic safflower
oil is virtually free of sulfur.

Castor Bean: (Ricinus communis), a member of Euphorbiaceae,
has been cultivated for centuries because of the energy rich oil it produces in
its seeds. The seeds contain between 40% and 60% oil that is rich in
triglycerides. The crop grows 3 to 10 ft, producing several branches with
terminal spikes that are 6 to 12 in. long. Each spike bears 15 to 80 capsules,
which contain within each of them three seeds. Yields of about 2,200 lb/acre
have been reported in Nebraska tests. Average production is estimated at 750
kilos per hectare. The seeds and roots of the plant contain high concentrations
of ricin, a poison, which is also present in lower concentrations throughout
the plant making it a great gopher poison.
The crop is also harmful to humans and livestock and for this reason
caution must be taken in disposal of the crop after cultivation.

Sesame: (Sesamum indicum L.) belongs to the Pedaliaceae
family. It is an annual herb that can grow to a height of 60 inches. The seeds
that it produces, which have been estimated to achieve yields of as much as
2,300 lb/acre under irrigation in California, consist of approximately 50% oil
and 25% protein. Sesame seeds contain 825 calories per cup of which 644 are
from fat. Among edible oils, sesame oil has the highest antioxidant content,
namely due to the presence of the compound sesamin; this allows for greater
shelf life plus improved flavor. In addition the seeds with hulls are rich in
calcium (1.3%) and provide a valuable source of minerals for both human and
livestock consumption.

Quinoa: (Chenopodium
quinoa) is grown primarily for its highly nutritious edible seeds, which
are small yellow flattened spheres, approximately 1.5 to 2 millimeters in
diameter; however, the leaves of the plant can also be eaten. The seed coat
contains bitter saponin compounds that must be removed before human
consumption, but it is this bitter pericarp that keeps the crop nearly
untouched by birds. In addition to containing a balanced set of essential amino
acids for humans, quinoa’s protein content (12%–18%) is very high, making it an
unusually complete foodstuff; this means it takes less quinoa protein to meet
one's needs than it does wheat protein. Quinoa is a good source of dietary
fiber and phosphorous and is high in magnesium and iron; it is gluten free and
considered easy to digest. There are about 1480 calories in one pound of quinoa
flour or seeds (55.3% carbohydrates, 13.1% protein, 5.8% fat, 13.6% fiber,
9.3% water, and 2.9% minerals).

Oats: (Avena
sativa) are an annual grass that reach 1.3 meters in height. Producing an
average of 125 bushels per acre, which is 8,000-12,000 pounds per acre of biomass,
oats are primarily grown for livestock feed; in fact less than 5% of the total
production in this country is for human consumption (mainly as oat flour). Oat
is the only cereal containing a globulin or legume-like protein, avenalins, as
its major (80%) storage protein. The protein content of the hull-less oat
kernel, or groat, ranges from 12–24%, the highest among cereals. Oats help
conserve soil, they require relatively less chemical fertilizers, pesticides
and herbicides; they reduce water contamination by agricultural chemicals, and
provide nutritional benefits to both humans and animals.

Corn: (Zea mays
L.), the single largest U.S. crop, is increasingly being used as a biomass
fuel. It is currently harvested from 30 million hectares within the United
States, which is almost ¼ of all the harvested cropland in the country. The
average yield of moist corn grain is 8600 kilograms per hectare; that is
approximately 150 bushels per acre. According
to the National Corn Growers Association, 1.3 billion bushels of corn were
allocated towards ethanol production in 2004. David Pimentel, a
professor from Cornell estimates that one acre of U.S. corn can be processed
into about 328 gallons of ethanol, but planting, growing and harvesting that
much corn requires close to 140 gallons of fossil fuels and costs $347 per
acre; that is $1.05 per gallon of ethanol before the corn even moves off the
farm, meaning that 70% more energy is required to produce ethanol from corn
than the energy that ethanol contains. No research has been done; however, as
to whether corn may serve as a sustainable energy crop when grown organically
and at a much smaller scale. Corn residues, including the stalk and cob may
also prove useful in future energy production.

Energy Inputs to Corn Production

Nitrogen fertilizers (all fossil
energy)

Phosphate, potash, and lime (mostly
fossil energy)

Herbicides and insecticides (all
fossil energy)

Fossil fuels: diesel, gasoline,
petroleum gas, and natural gas

Electricity (almost all fossil energy)

Transportation (all fossil energy)

Corn seeds and irrigation (mostly
fossil energy)

Infrastructure (mostly fossil energy)

Labor (mostly fossil energy)

Potato: (Solanum
tuberosum) a member of Solanaceae, ranks with wheat and rice as one of
the most important staple crops in the human diet around the world.Within 10 g of the tubers are 80 calories (320
kJ). A medium potato (150g/5.3 oz) with the skin provides 27 mg vitamin
C (45% of the Daily Value), 620 mg of potassium (18% of Daily Value), 0.2 mg vitamin
B6 (10% of Daily Value) and trace amounts of thiamin, riboflavin, folate, niacin,
magnesium, phosphorus, iron, and zinc. Moreover, the fiber content of a potato
with skin (2 grams) equals that of many whole grain breads, pastas, and cereals.

Buckwheat: (Fagopyrum
esculentum) is a short season crop that does well on poor, sandy, somewhat
acidic soils. Plants will begin blooming in about 40 days from seeding, with
the first seeds mature after an additional 40 days. This rapid production
allows for many harvests throughout the year makes the crop ideal for growing
as a local source of calories. The seed is an achene, similar to a sunflower
seed, with a hard outer shell and soft inner meat. Most of the buckwheat grain
utilized as food for humans is marketed in the form of flour but whole grain
may be used in poultry scratch feed mixtures as they are high in protein. As
well as being a food crop, buckwheat is used for its biomass.

Amaranth: (Amaranthus sp.)
with 60 recognized species, makes up its own family, Amaranthaceae. The
herbaceous annual grows 5 to 7 feet, with broad leaves and a showy flower head
of small, red or magenta, flowers. The seed heads resemble corn tassels, but
are somewhat bushier, composed of tiny (1/32"), lens shaped seeds that are
a golden, creamy, tan color. Amaranth resists heat and drought; it has no major
disease problems, and is among the easiest of plants to grow. Each plant is
capable of producing 40,000 to 60,000 seeds that like buckwheat and quinoa,
contain protein that is unusually complete for plant sources. The leaves also
are a very good source of vitamins including vitamin A, vitamin B6, vitamin C,
riboflavin, and folate, and dietary minerals including calcium, iron, magnesium,
phosphorus, potassium, zinc, copper, and manganese. Several studies have shown
that like oats, amaranth seed or oil may benefit those with hypertension and
cardiovascular disease.

Black Salsify: (Scorzonera
hispanica) is a member of Asteraceae cultivated for its calorie rich black taproot
which grows up to one meter long and up to 2 cm in diameter. In ½ cup of Black
Salsify are 50 calories; potassium, calcium, phosphorus, iron, sodium, and vitamins
A, B1, E and C are also present. In addition to the root, the foliage is edible
and functions as a great nutrient source for livestock as well as a source of
salad greens for humans. Because the crop is relatively untroubled by pests and
cold tolerant it makes an easy to manage crop for the organic farmer.

Parsnip: (Pastinaca sativa) a member of Apiaceae, offers a great source of calories during the
winter while the rest of the garden is dormant. Parsnips are very frost
resistant; in fact, frost is necessary to develop the flavor and nutrients for
the hardy root crop. In 100
g of parsnip root are 55 calories; that is 230 kJ of energy. Parsnips are richer
in vitamins and minerals than its close relative the carrot, and in addition to
providing calories to the diet, they are a good source of fiber, folate,
magnesium, potassium (600 mg per 100 g), Vitamins C and E, calcium, iron, thiamin,
riboflavin, niacin, and B6.

Barley: (Hordeum vulgare)
a member of Poaceae, can be grown in both spring and autumn. It retains yields
under harsh conditions
and poor soils where other grains don’t produce well. Barley contains twice as
many fatty acids as wheat which accounts for its 10% higher calorie count. In
addition barley contains 68% more thiamin, 250% more riboflavin and 38% more
lysine than wheat, giving barley a more balanced protein. One hundred grams of
barley contains 135 calories and provides 54.5% of the recommended daily
fiber (both soluble and insoluble fiber). It has been documented in both
the Journal of the American College of Nutrition and the American
Journal of Clinical Nutrition that increase barley consumption correlates
with cholesterol reduction.

Lentil: (Lens culinaris)
a member of Fabaceae, grows 15 inches tall and produces many pods which contain
within each of them two seeds. Estimated yields in excess of 2,000 lb/acre have
been achieved at small levels of production. Protein content of the crop ranges
from 22 to 35%, but the nutritional value is low because lentil is deficient in
the amino acids methionine and cystine. In 100g of lentil are 371 calories. Apart
from a high level of proteins, lentils also contain dietary fiber, vitamin B1,
and minerals. Red (or pink) lentils contain a lower concentration of fiber than
green lentils (11% rather than 31%). Lentil provides more folic acid than any
other unfortified food. One cup of cooked lentils contains 90% of the
recommended daily allowance. As a result consuming lentil effectively reduces
homocystein blood levels, reducing risk for heart problems.

Rye: (Secale cereale) a member of Poaceae, grows in both spring
and august and function as a cover crop in addition to providing carbon and
calories for the small scale farm. Yields of 70 to 80 bu/acre can be obtained
with good management. The food value of rye consists of 1.5% fat, 73.9% complex
carbohydrates, and 12.2% protein. The energy content of the grain is
intermediate to that of barley and wheat. It contains 335 calories within100g
(1402kj). Although rye flour does not develop true gluten, it is the only
cereal grain other than wheat to have the necessary qualities to make bread.

Millet:
(Panicum miliaceum) a member of Poaceae, grows well on poorly fertilized and dry soils and fits well in hot
climates with short rainfall periods and cool climates with brief warm summers.
For this reason it is considered a staple food crop among 1/3 of the world’s
population. Millet is highly
nutritious, non-glutinous and like buckwheat and quinoa, is not an acid forming
food so it is easy to digest. In fact, it is considered to be one of the
least allergenic and most digestible grains available and it is a warming grain
so will help to heat the body in cold or rainy seasons and climates. Millets
are rich in B vitamins, especially niacin, B6 and folacin, calcium, iron,
potassium, magnesium, and zinc. The
seeds are also rich in phytochemicals, including Phytic acid, which is believed
to lower cholesterol, and Phytate, which is associated with reduced cancer
risk. Contained within 100g of millet seed are 228 calories with 66,000
to 81,000 seeds/lb. Each seed contains nearly 15% protein. Yields up to 2500 to
2800 lb/acre are realistic for this climate.

Fababean: (Vicia faba ) is
the plant for which the bean family, Fabaceae, was named. At about 25% protein,
the crop is very nutritious and high in energy, and is frequently cultivated
for human and livestock consumption. Average yields of 2261 lbs/acre have been
achieved under irrigation. Frost hardy to about 7°F,
it is one of the most important winter crops for human consumption in the
Middle East. More so than a food crop, fababeans are the most efficient of all
legumes at fixing nitrogen within the soil. The crop is capable of fixing up to
200 pounds of nitrogen per acre. In addition their extensive root system breaks
up soil to 2 feet deep, and brings up soluble nutrients from 10 feet deep.

Alfalfa: (Medicago
sativa) is a cool season perennial legume, growing to a height of 1 meter.
Like other legumes, its root nodules contain bacteria, Sinorhizobium
meliloti, capable to fix nitrogen (estimated to fix 83–594 kg N/ha/yr),
producing a high-protein feed, giving it the highest feeding value of all
common hay crops. Forage yields are 5–75 MT/ha per year (with 8–12 cuttings per
year). Seed yields are 186–280 kg/ha annually. Alfalfa grows well in the cool
months, producing enough vegetation to yield the energy equivalent of 2 to 7
barrels of oil per acre. Basing estimates on average alfalfa hay yields,
participants at the Fourth Annual Alfalfa Symposium concluded that we could get
nearly a ton of leaf protein per acre from alfalfa. This would mean 55 million
tons of protein from 62.5 million acres—about 10 times what Americans need in
their diet. Residues remaining after protein extraction would yield the
equivalent of 250 million barrels of oil in residues.

Hairy Vetch: (Vicia villosa) a member of Fabaceae, is the only vetch species that can be
fall-seeded and reach maturity the following July. Capable of enriching the soil with nitrogen up to 60 to 120
lb/acre, and aerating soil up to depths of 30-85 cm, the legume is used primarily
for soil improvement. Hairy vetch is also said to facilitate the availability
of potassium to other, shallower-rooted, crops The protein content of vetch hay
ranges from 12 to 20%; however, and can function as a beneficial food source
for livestock. Vetch produces a hay yield of 1.5 to 3.5 ton/acre dry weight.

White Clover: (Trifolium
repens) a member of Fabaceae, is the
world’s most widely grown clover. It is often under sown with cereals to
provide a perennial source of nitrogen and increase their yield. White clover yields of 100 lb of N/acre have
been documented. White clover can be “frost seeded” (in early spring when the
soil is still frosted) into existing grass pastures to improve pasture
production and quality. It is highly nutritious and palatable and aside from
improving the soil of the pasture is offers a source of winter forage for
livestock. The protein content of white clover will exceed 15% and the
digestibility 70%. Dry matter yields will range from 2000 to 4000 pounds per
acre per season depending mainly on soil moisture. The crop tolerates trampling
and mowing, and can therefore be seeded as an alternative to conventional
lawns.

Comfrey: (Symphytum officinale L.) is a
prolific perennial herb belonging to the Borage family (Boraginaceae) that has
long been recognized by organic gardeners for its great usefulness and
versatility, both medicinally and as a fertilizer. Because the majority of
comfrey under cultivation is hybridized, it is typically propagated from root
cuttings. It is a sturdy plant, reaching a height of 2 to 3 1/2 feet with very
large, hairy lower leaves, as much as 15 to 20 inches long. Its roots draw
nutrients from deep in the soil to produce the energy rich foliage that offers
many methods of application as a fertilizer.

Comfrey
offers many uses as a fertilizer:

-
Comfrey as a compost activator

-
Comfrey as liquid fertilizer

-
Comfrey as a mulch

-
Comfrey as a potting mixture ingredient