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t
his article is the twelfth in a series of articles highlighting
a specific pasture crop species that can play an imperative
role in conservation agriculture (CA)-based crop-pasture
rotations. Besides improving the physical, chemical, hydro-
logical and biological properties of the soil, such species,
including annual or perennial cover crops, can successfully
be used as animal feed.
Livestock production systems are in many ways dependant on the
utilisation of pasture species, in this case as a pasture ley crop,
and can therefore become an integral component of CA-based
crop-pasture rotations. It is imperative however to identify a
pasture species fulfilling the requirements of a dual purpose crop,
i.e. for livestock fodder and/or soil restoration.
This article focuses on an annual pasture crop commonly used in
a short one winter season rotation as a cover and green manuring
crop either succeeding a summer annual or perennial species. Green
manure cropping is a practice not well understood or economical-
ly justified in South Africa, as it seems expensive, because of the
seedbed preparation, establishment and potential waste or rather
the unknown value of incorporation.
With the rising cost of fertilisers and the objective of sustained soil
fertility and soil health improvement, these options can provide op-
portunities.
Avena sativa
/oats/
hawer
Common oats is a cool-season, annual cereal crop, and is becom-
ing a very well-known quick cover crop that has the ability to meet
numerous soil conservation priorities. Its tropical relative, the “black
oats” variety, has also received support from many who have used
it in certain no-till systems and other agricultural systems in other
parts of the world.
Common oats is an upright, annual grass that can reach a height
of 1,5 m. It has a fibrous root system and its growing cycle can be
anything between 60 to 75 days depending on the cultivar and the
environment in which it is grown. Its seed is inexpensive and there
are many adapted varieties.
Agro-ecological distribution
Oats prefers cool, moist climates on well-drained soils, but this crop
is adapted to many soil types. It can tolerate soil pH levels ranging
between 5,5 to 7, but some varieties can tolerate soil pH levels as
low as 4,5. It has a wider pH adaptability than wheat or barley, and it
has a low lime requirement.
This crop has the ability to grow much better in wet soils than other
cereal crops, however, it only requires approximately 350 mm of
moisture for growth and is therefore regarded as a good crop for
moisture conservation. There are numerous cultivars available
from various seed merchants.
Management and utilisation
Broadcast or drill seed to a depth of 1 cm - 2,5 cm and disk lightly.
Seeding rates of up to 100 kg/ha can be used in winter rainfall areas
or under irrigation. In summer rainfall areas under dryland produc-
tion, 50 kg/ha - 75 kg/ha of seed can be planted.
If the soil is sufficiently moist, shallow seeding promotes rapid
seedling emergence with reduced incidence of root rot disease. Of-
ten this species is not fertilised with nitrogen (N), as it is used to
soak up excess nitrogen in the profile and prevent it from being lost
through leaching.
WAYNE TRUTER,
University of Pretoria,
CHRIS DANNHAUSER,
Grass SA,
HENDRIK SMITH,
Grain SA and
GERRIE TRYTSMAN,
ARC-Animal Production Institute
Integrated crop and pasture-based
livestock production systems
– Part 12
AGRICULTURE
Conservat ion
Series
“
If the oats is to be used
for cattle production, it can
either be grazed with
sufficient periods of rest
for regrowth, or hay and/or
silage can be made.
“
ON FARM LEVEL
Conservation agriculture
Februarie 2015
36