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Fertilisation during establishment is important, and lime will not
necessarilyensuresignificantlyhigheryields,however,raisingthesoil
pH toabove6,will facilitateoptimal assimilationofnutrients required
for growth and resistance to growth limiting factors. It is imperative
that thephosphorus (P) content of the soil shouldbe sufficient, since
research has shown that blue buffalo grass seedlings have a high
P requirement.
If general fertiliser recommendations are adhered to, it will not be
necessary to fertilise P within three years. The following year’s
superphosphate can be applied to maintain the soil P content at
15 mg/kg soil and above. In highly productive areas, it can be
beneficial to split P applications between spring and summer.
With regards to nitrogen (N) fertiliser recommendations, it often
very difficult to obtain a clear recommendation since it is largely
dependent on the rainfall being the determining factor. A very
common recommendation based on research findings at Mara
Research Station, ranges between 40 kg - 100 kg N/ha for an area
receiving a rainfall of 400mm - 800mm.
Theseapplicationscanbesplitover twoperiods.With theproduction
of hay, and the resultant high removal of potassium (K),Kwill need to
be applied regularly in the formof potassium chloride (KCl) at a rate
of 50 kg - 100 kgK/ha.
Management challenges
One of themost important factors that determine the quality of the
blue buffalo grass is the age of the material since the last harvest.
The older the material, the less acceptable the hay will be for
the animal.
Digestibility and therefore nutritional value will decrease substan-
tially as the plant becomes more mature. For these reasons, the
farmer should try to cut hay every six to eightweeks (approximately
750mm tall).
Higher hay yields canbe obtained, but possiblywith lower quality if
intervals between harvests are longer, therefore less harvests. The
quality of hay cut at the correct stage, can be sufficient tomaintain
dry andpregnant cattleduring thewintermonths.
With respect to grazing, animals tend to graze the leaf material
more selectively than the stem. If the animals are forced to eat the
stem material, it can be expected that an insufficient amount of
feedwill be available andwill negatively affect animal production.
A good practice to revitalise grazed blue buffalo grass pasture is to
aerate the pasture with a tined implement every two to three years
depending on the soil texture and themoisture content of the soil.
A clay soil is less dependent on this practice thanmost other soils,
and it is advisable to apply this practicewhen soils arenot toodry.
Soil conservation and health benefits
Blue buffalo grass is a species that is widely adapted and has the
ability togrow invarious soil conditionsandcanoptimallyuseall the
resources available to it. Since it iswell adapted to drier conditions,
it becomesveryattractive touse thisspecies to rest soilsand restore
soil quality under extreme climatic conditions.
With the amount of dry matter produced under variable moisture
conditions, this species has the ability just as many other sub-
tropical grasses have, to lower the soil temperatureswhich facilitate
further seed germination, as well as preserving moisture from soil
evaporative loss. This preserved moisture is rather used for plant
growthwhichwill ultimately contribute toorganicmatter which can
partly be used for animal feed, decomposed to soil organic matter
and thenalsobeacompetitor forunwanted,worthlessweedspecies.
Animal production aspects
It isgenerallyknown that bluebuffalograsscanbecomeunpalatable
theolder it becomesandespeciallywhen it growsout too tall.At this
stage toomany thick stems developwhich the animals avoidwhen
grazing.
Just as production is affected by rainfall and fertiliser, so also will
the grazing capacity. Grazing capacity values established in thepast
were 1,2 LSU/ha/180 days on average for both the Bloemfontein
and Mara district with a long-term average rainfall ranging from
400 mm to 550 mm. On the Springbok flats grazing capacities of
1,1 and 1,5 LSU/ha/180 days have been determined; however it can
be as low as 0,8 LSU/ha/180 days whereas high rainfall or irrigated
areas it can increase to 2,5 LSU/ha/180days.
Animal productiononbluebuffalograsscandeliver liveweightgains
of 140 kg/ha - 185 kg/ha and can go up as high as 345 kg/ha. Many
researchers and authors recommend that this species only be used
for younggrowing animals for themost economic results.
On theotherhandhayproductioncanbeas lowas2 tons/ha in lower
rainfall regions, however yields of up to 12 tons/ha in high rainfall
regions have been obtained. With a six to eight week regrowth of
bluebuffalograss, that hasbeen fertilisedwell, crudeproteinvalues
of up to 12%, crude fibre values of 35% - 50%, and a digestibility of
55% - 65% canbe achieved.
As part of an animal production system, it is important to have
alternative uses for pasture species and blue buffalo grass has the
potential to also be used as a foggage. This species can therefore
retain some quality in winter to maintain animal weight with the
supplementationof awinter lick.
Grain crop production
In theNorthWest and central parts of our countrywhere grain crop
production is prominent, blue buffalo grass can typically be used in
acroppingsystem for aperiodof around fiveyears.After thisperiod,
thesoil shouldbesufficiently restored tocultivateannual graincrops
under aCA-system.
Herbicides kill the pasture quickly and the pasture residues remain
on the soil surface providing cover that limits erosion, enhance
water infiltration and reduces their rate of mineralisation. Once
a decision is made to terminate the ley, all pasture components
should be considered as “weeds” that need to be removed. They
shouldno longer be regarded as a sourceof fodder for livestock.
Depending on the pasture species and situation (e.g. dry or wet
area), the pasture could be killed a season before planting grain
crops toallow thesoil profile tobe replenishedwithwater. Thewater
requirement of the first cropplanned after pasturewill influence the
timingof removal of thepasture.
Reliable and timely seasonal rainfall forecasts may assist in this
planning. Following the pasture phase, grain crop yield will be
restrictedunless thesoilwater profile is replenished.After removing
the pasture, weeds in the fallowmust be controlled to conserve soil
water tomaximise thebenefit 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
(basedonsoil fertility levelsandyield targets),weedandpest control
practices shouldbe followed.
Conclusion
Cenchrus cilliaris
(bluebuffalograss/
bloubuffelsgras
) is regarded as
oneof thebest pasture species adapted todryandwet conditions. It
has theability toproducegoodqualitypasture ifmanaged correctly.
As with many other sub-tropical species, this species can also be
mismanaged and then provide very little value at all. With good
establishment, rainfall and fertility (irrespective of howmuch), this
species can offer fantastic grazing and high quality hay for animal
production, while restoring the soil for futuregrainproduction.
For more information, contact Dr Wayne Truter at
wayne.truter@
up.ac.za
, Prof Chris Dannhauser at
Dr Hendrik Smith at
or Mr Gerrie
Trytsman at
