The phosphorus (P) status of these soils planted to this species
should be in the order of 15mg/kg - 20mg/kg soil, and if potassium
(K) shortages of less than 80 mg/kg soil are noted, potassium
chloride (KCl) shouldbeused to increase these soil K-levels.
Very little is knownabout thepotential valueof existingcultivarsand
ecotypes of this species, especially under different environmental
conditions. A tremendousamount of research is required tobedone
regarding the best management and utilisation practices for this
species.
There is evidence that white buffalo grass reacts best to mild
defoliation, and that frequent defoliation below a height of 10 cm
can negatively affect the regrowth potential of this species. Correct
rotational grazingwith theemphasisongrazingheight and frequency
of defoliation inaddition to themaintenanceof good soil fertility,will
ensure a highqualitypasturewithhigh yields overmany years.
Yields of up to 20 tons/ha under irrigation have been obtained. Dry
matter yields of between 6 tons/ha - 14 tons/ha, however, aremore
realistic. This depends onmany factors, such as rainfall, climate and
soil quality.
Management challenges
In order to ensure good production of this species, it is important
to have the correct amount of rainfall or irrigation. It is however
sensitive towater-logged soils, and if irrigated, it should be on soils
that arewell-drained. If planted in dry areas, it is important to plant
the species in 1m to 2mwide rows.
Medium to high annual fertiliser applications are essential to ensure
high production as well as the survival of a stand of white buffalo
grass, especially in sandy soil. Red soils (Hutton types), haveproven
to produce good stands of Guinea grass, heavy soils however, not
as good, and sandy soils should more likely be avoided. Regular
overgrazing (below 10 cm height) can significantly reduce the
lifespanof this grass.
It is difficult to make hay from this species, as it produces high
volumes of material which dries out slowly and preferably requires
amower with a crimper and significant windrowing to prepare it for
baling. When hay is made from this species, it offers high quality.
This species can contain an anti-quality factor such as oxalic acid;
it can occur under stressful growing conditions and horses are for
instance sensitive tohigh values.
Soil conservation and health benefits
Research has shown that white buffalo grass has the ability to grow
on saline soils. As with Rhodes grass, it is important that soils that
are often planted to grain crops and especially under irrigation, can
be cropped in rotationwithwhitebuffalograss.
This practice will help reduce the impacts of high salinity caused
by excessive irrigation. Not only will this grass grow on these
saline soils, the species will assimilate some of the salts, whichwill
contribute to the inherent palatability of the species. The excess
levelsof remaining saltswill be leached from the root zonewhile the
perennial pasture is being irrigatedover time.
Animal production aspects
This species is known to have a relatively good grazing capacity
of one to two livestock units (LSU) per hectare. An additional
advantage of this grass is the good nutritional value during winter,
which confirms its foggage value. During winter, this species can
have a digestibility valueof approximately 45%with a crudeprotein
content of at least 6%. One of the main reasons for this species to
retain its quality in winter is due to the fact that the carbohydrates
and other important nutrients are stored in the aboveground plant
components andnot the roots likemanyother species do.
In the summer it can be expected to achieve digestibility values
of anything between 53% - 62% with a crude protein value of a
minimum of 6% - 11%, whereas some studies have noted crude
protein values of up to 20% - 23%, under intensive fertilisation and
irrigationpractices.
Grain crop production
After establishing a typical ley crop system using white buffalo
grass for aperiodof around fiveyears, the soil shouldbe sufficiently
restored to cultivate annual grain crops under a CA-system.
Herbicides kill the pasture quickly and the pasture residues remain
on thesoil surfaceprovidingcover that limitserosion, enhancewater
infiltration and reduces their rateofmineralisation.
Onceadecision ismade to terminate the ley, all pasturecomponents
should be considered as “weeds” that need to be removed. They
shouldno longer be regarded as a sourceof fodder for livestock.
Dependingon thepasturespeciesandsituation (e.g. dryorwet area/
season), the pasture could be killed a season before planting grain
crops toallow the soil profile tobe replenishedwithwater. In certain
situations/areas, an annual legume could be planted directly after
termination of the ley crop, such as grazing vetch (
Vicia villosa
) as
a winter crop or soybeans (
Glycine max
) in the following summer,
followedbymaize (
Zeamays
) in the crop rotation.
The water requirement of the first crop planned after pasture will
influence the timing of removal of the pasture, especially in the
dryer,westerngrainproduction regionsofSouthAfrica. Reliableand
timely seasonal rainfall forecastsmay assist in this planning.
Following thepasturephase, grain cropyield indryer regionswill be
restrictedunless thesoilwater profile is replenished.After removing
the pasture, weeds in the fallowmust be controlled to conserve soil
water to maximise the benefit of the ley. A suitable no-till planter
should be used to plant the grain crops directly into the residues of
the pasture crop, without any other cultivation practice disturbing
the soil.
Normal integrated fertiliser (based on soil fertility levels and yield
targets),weedandpest control practices shouldbe followed. During
the transformation phase, after newly established CA grain fields
(e.g. during the first five years after termination of a ley crop), a
30% increase in N-fertilisers is recommended onmaize, due to the
immobilisationof N in the soil.
Conclusion
White buffalo grass is definitely a sub-tropical grass species that
shows tremendous potential in South African integrated crop and
livestock production systems. Not only does it produce high yields
and quality grazing, it has the potential to produce good quality
foggage and silage, and is essential in any fodder flow programme,
unless the climate and rainfall restricts its use.
This species also has the ability to be grown on saline soils and
provides the opportunity to rest and help restore cropping lands
under irrigation systems. Although it should always be kept inmind
that proper nitrogen fertilisationshouldbedoneand thephosphorus
andpotassium status of the soil has tobe as suggested earlier.
ON FARM LEVEL
Conservationagriculture
CONSERVATIONAGRICULTURE
Julie 2014
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