55
May2014
ON FARM LEVEL
Conservationagriculture
An important condition for using Smuts finger grass as foggage is
that thepasturehas tobe rested frommid-January for the rest of the
growing season. If this pasture is tobe fertilisedbefore it is used for
foggage, thenmid-January is also themost suitable time todo this.
WhenSmuts finger grass is to be used as a green pasture, it is very
seldom that it is ready for grazing before the middle of November.
Once grazing commences it can be used until end of April and if
good foggage is prepared, it canbeuseduntil the endofMay.
Rotational grazingwithhighgrazingpressure isessential tooptimally
utiliseSmuts finger grass, especiallywith sheep. Cattlecanhowever
utilise this pasture efficiently using a continuous grazing system. If
Smuts finger grass is fertilised well, year old weaners or slaughter
lams are the most profitable group of livestock to be kept on such
pastures.
Smuts finger grass is regarded as a very goodhay crop, particularly
with regards to the palatable leaves and stems. The grass however,
cannot be cut, dried andbaledon the same day, as these processes
take a bit longer than
Eragrostis curvula
for instance. If these
aforementioned processes are completed before being spoiled by
rain, then extremely highquality hay canbeproduced.
Management challenges
Theproductionandgrazingcapacityof thisgrassdependsgreatlyon
the soil type, fertilisation level, rainfall andmanagement. A common
growth trend isnoted forSmuts finger grass,where it startsgrowing
around themiddleof October and stops growing inMarch/April.
The most active growth stage is the middle of November until the
end of January. The growth distribution on a percentage basis is as
follows: 15% for November, 35% for December, 28% for January,
12% for February, 6% forMarch and 4% for April.
As canbe seen,mostmanagement activities such as cutting, baling
and fertilisation need to be conducted in December/January if this
pasture is to be used as a dual-purpose pasture. This is however in
the middle of the peak rainy season, which highlights the evident
management challenges. Even though this pasture crop is grownon
a varietyof soils, it will not survivewaterlogged conditions.
Animal production aspects
Dry matter (DM) production values of as high as 12 tons/ha to
18 tons/ha has been achieved under optimal climatic conditions
and good fertilisation practices. The common production values
expected for summer rainfall areas in the western parts of the
countrywhere the rainfall is between 400mm - 800mmper annum,
canbe as low as 1,5 tons/ha to 7 tons/ha.
For optimal production under grazing conditions, it is imperative
that Smuts finger grass should never be grazed shorter than 50mm
from the soil surface. A rest period of 30 to 60 days is essential for
sufficient regrowth tooccur before thenext grazing cycle.
The grazing capacity of Smuts finger grass can vary between areas
receiving different rainfall, and can be anything between 0,5 - 2,5
mature large stock units (LSU)/ha. The digestibility of this grass
can vary between 60% - 65% in the summer and drop to as low as
40% in winter. During the growing season a crude protein content
of between 12% - 22% can be achieved with good fertilisation and
rainfall, but canhowever beas lowas5% inwinterwithnoattention.
Soil conservation and health benefits
Smuts finger grass is a highly recommended pasture ley crop for
shallowandstonysoils. Themajor limitation to this recommendation
is that the grain cropped land will need to be removed from crop
production for at least five years since this grass establishes slowly.
Even if Smuts finger grass is known to establish slowly, the primary
valueof this pasture is endless, particularly from an animal nutrition
perspective as provided by hay, foggage, silage and summer and
autumn grazing. It is often noted that the secondary value of such
a pasture lies in the higher degree of soil nutrient build-up through
animal dung when highly palatable and nutritious pastures are
grazed.
With the increased occurrence of degraded natural veld, Smuts
fingergrasscanalsobe regardedasan important grass tobeused to
reinforcesuchpoorqualityveld.Aspreviouslymentioned, thisgrass
has an inherent palatability and awide adaptabilitywhichmakes it a
suitablegrass to interseed intodegraded areas.
Grain crop production
After establishing a typical ley crop system usingSmuts finger for a
period of around five years, the soil should be sufficiently restored
tocultivateannual graincropsunder 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 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.
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.
A profitable pasture
Smuts finger grass is regarded as one of the best quality and
adaptable grasses in South Africa. Even though it takes some time
to establish properly, it will always be known as one of the most
profitable pastures in a long term ley cropping system. It is a strong
perennial pasture, with a vigorous root systemwhich can ultimately
improve soil quality and contribute to livestock and grain crop
profitability and sustainability.
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
CONSERVATIONAGRICULTURE
