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During growing season, in-between cash
crops (as summer pasture ley fallow)
Crops such as babala, forage sorghum, cowpea, soybeans, mung
beans, dolichos lablab, velvet bean, sun hemp and jack bean can
be used. These multi-specie systems should preferably be grazed
twice in the growing season, once in early summer to maximise
root growth (five times more root growth after first grazing) and
once in late summer to increase organic matter decomposition
(see
Photo 3
). If required, crop growth could be terminated with her-
bicides or with a knife roller. Time of termination depends on the
need to store or conserve soil water for the next crop.
During growing season, simultaneously with
maize (as intercrop)
Non-climbers (such as cowpea, mucuna or velvet bean) or climbers
(dolichos lablab and velvet bean) can be sown two to eight weeks
after planting maize. Later plantings have less impact on maize
yield, however. The earlier the ley crops are sown, the greater the
soil protection and weed suppression obtained.
In smallholder systems, intercrops are also planted as food source,
such as dry beans or cowpeas, which residues could also be used
for animal feed (see
Photo 4
).
Pasture ley crops for a specific purpose
A suite of cover crops are available for producers to plant for a
specific purpose and can include the following (
species listed are
not limited and other options do exist
):
Quick forage which can be grazed
Oats, forage radishes, turnips, triticale and stooling rye, and annual
ryegrass, teff for dry lands, babala, forage sorghum and barley.
Start up or enhance no-till
Forage radish, turnips, babala and forage sorghum. Babala and for-
age sorghum can result in very high residue amounts for soil cover.
Prevention of soil erosion
Grasses have fibrous root systems to bind soil, and the best
grass cover crops include babala, forage sorghum, cereal rye,
annual ryegrass, oats, wheat and barley. Other cover crops include
lablab, buckwheat (with a shallow fibrous root system), cowpea and
winter pea.
Pasture ley crops for soil carbon build-up
(to increase C:N ratio)
Summer annuals: Babala and forage sorghum.
Winter annuals: Cereal rye, annual ryegrass, triticale, oats, wheat
and barley.
Perennials: Sub-tropical grasses, for example Rhodes grass, Smuts
finger grass, weeping love grass, Guinea grass, blue buffalo grass
and tall fescue (see
Photo 5
).
Pasture ley crops for soil nitrogen increase
(to decrease C:N ratio)
Summer annuals: Cowpea, soybeans, mung beans, dolichos lablab,
velvet bean, jack bean and sun hemp.
Winter annuals: Winter pea, red clover, sweet clover, vetch, serradel-
la and lupines.
Perennials: Lucerne, poor man’s lucerne and fine stem stylo.
Requires no herbicide to kill
Oats, cowpea, winter pea, forage radish and turnips.
Reduction in compaction (deep rooted)
Babala, forage sorghum, annual ryegrass, forage radish, sweet clo-
ver, cereal rye, oats and dolichos lablab.
Recycle excess nutrients (nitrogen,
phosphorus)
Forage and tillage radish, turnips, annual ryegrass, cereal rye, oats,
wheat, babala, forage sorghum, sweet clover, winter pea, cowpea,
red clover and vetch species.
In general, legumes need P for N fixation but are unfortunately
poor users of P in the soil. Since legumes can contribute to soil acidi-
fication, it can result in P becoming more available when P is fixed
and limiting.
In general, grass cover crops store and supply more P than leg-
umes because they have a finer root system and more surface area
than legumes with a taproot. In mixed legume-grass pastures, the
legume cycles N to the grass and the grass cycles P to the legume.
Natural herbicides or allelopathic effects for
weed suppression
Cereal rye, forage radish, oats, barley, babala and forage sorghum.
Annual ryegrass, cereal rye, and sorghum may be used for control-
ling soybean cyst nematodes.
Attract beneficial insects
Buckwheat, sweet clover, red clover and other selected clover and
vetch species, sun hemp, sunflower, dolichos lablab and sorghum.
Tolerate wet soils
White clover, red clover, other selected clover species, annual rye-
grass, cereal rye, wheat and oats.
Tolerate heat and drought
Dolichos lablab, cowpea, vetch species, mung beans, sweet clover,
sorghum, babala, barley and teff.
Cold tolerant
Stooling rye, oats, wheat, triticale, winter pea and selected clover
species.
CONSERVATION AGRICULTURE
ON FARM LEVEL
Conservation agriculture