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tomicro-nutrient poor soil. It is therefore imperative that such soils
which indicatemicro-nutrient deficiencies, are amended to improve
thequalityof thepasturewhereneeded.
Since bottle brush grass is known to be a palatable grass under
harsh growing conditions, it can be used confidently as both a
summer andwinter grazing (foggage). Bottlebrushgrasshasproven
itsvalue in theNorthWest provinceas anexcellent foggage species.
One of the most important contributing factors to this was leaf
abundance andquality.
Management challenges
As previouslymentioned, bottle brush grass has verywoolly seeds
and the establishment of this seed can therefore be difficult on a
windyday.
Wind erosion and waterlogged conditions can create problems for
successful establishment. Seed coating technologies can facilitate
this process to ensure better establishment of the seed. There have
been reports that bottle brush grass should not be irrigated, since
this led to rust which affected the health of the plant and resulted
in its degeneration. This grass is also not recommended for hay
production.
Soil conservation and health benefits
Bottle brush grass has shown its tolerance to dry conditions, this
is normally strongly correlated to verypoor quality soils.
Quite often the soils which are planted to bottle brush grass are
sandier soils that are susceptible towind erosion. This species how-
ever, has the potential to grow in theses sandy and often nutrient
poor soils andbinds these soils toprotect them against eroding.
Asa resultof thisspecies’ excellentwaterandnutrientuseefficiency,
the amount of nutrients and water used for growth from the soil is
replaced by an insurmountable soil organic matter that is deficient
before. Indirectly this creates better soils structure, improveswater
holding capacity and provides an energy source for soil micro-
organisms which are subsequently responsible for better nutrient
availability and assimilation.
Animal production aspects
With regards to bottle brush grasses’ production and quality, it
has been noted that it can be expected to carry one large stock unit
(LSU) per 5 ha - 6 ha under dryland conditions in the drier bushveld
regionswith a rainfall of approximately 400mm.
In higher rainfall conditions of approximately 600 mm per growing
season, it ispossible to carryone LSUper 2ha - 3ha. Actual grazing
capacity numbers obtained in the Vaalwater region, have indicated
that one LSU/ha for 80 days in the summer is achievable, and as
a result, up to 112 kg/ha of beef can be produced according to
Dickinson
et al
., (1990).
This amounts to 0,4 LSU/ha/180 days or 2,5 ha/LSU/180 days. In the
western regions of theNorthern Cape Province, Fourie
et al
., (1984)
obtained 100 LSU grazing days per hectare onmature bottle brush
grass. This results in a grazing capacity of 0,5 LSU/ha/180 days or
3ha/LSU/180days.
It is commonly known that bottlebrushgrasshas a lower drymatter
(DM) production than the other well-known drought tolerant blue
buffalograss.
A general rule of thumb used to estimate dry matter production,
is 0,75 ton/ha per 100 mm rain received. As a result of a higher
utilisation percentage (± 90%), this will compensate for the lower
DM production obtained, since livestock production is generally
muchbetter thanwith this grass.
Research in the FreeState has shown that the crude protein content
of bottle brushgrass can vary between 6% and 10% in the summer,
and in winter it can go below 6%. The digestibility has also been
measured tobe approximately 55% in thegrowing season and even
as low as 50% inwinter in the summer.
Conclusion
The drought tolerant sub-tropical bottle brush grass has been a
reliable pasture for many decades. In areaswhere soils are nutrient
poor and the rainfall is low, this species has the ability to provide
goodqualitypasture for optimal livestock production.
Where soils have become depleted through intensive tillage in an
area where a relatively acceptable rainfall is received, this species
will flourishandprovideanopportunity to improve thesoil’sphysical
condition and to some extent its nutritional status, while providing
goodqualitygrazing throughmoreof thegrowing season right up to
themiddleof winter.
For more information, contact Dr Wayne Truter at
wayne.truter@
up.ac.za
, Prof Chris Dannhauser at
Dr Hen-
drik Smith at
orMr Gerrie Trytsman at
ON FARM LEVEL
Conservationagriculture
CONSERVATIONAGRICULTURE
