ON FARM LEVEL
Conservationagriculture
t
his article is the seventh in a series of articles highlighting a
specific pasture crop species that canplay an imperative role
inconservationagriculture (CA)basedcrop-pasture rotations.
Besides improving the physical, chemical, hydrological 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 soil restoration.
Anthephora pubescens
/bottle brush grass
(
borseltjiegras
)
Bottle brush grass is a perennial, tufted grass with a single ear
inflorescence that grows on long, thin tillers.
The length of the tillers can vary from anything between 400 mm
- 1 200 mm. The leaves have a typical blue-green colour and vary
betweenhairy tohairless. Different ecotypesof thegrasshavebeen
evaluated in the past at the Vaalharts Research Station, however to
date, the two most common cultivars on the market are Common
andWollie.
Agro-ecological distribution
Bottle brush grass is found widely in South Africa and is adapted
to various growing conditions. It grows mostly on sandy soils and
is often grown on high clay content soils. The best production has
been achievedon soilswith a relatively neutral pHof 6,5.
One of themost attractive characteristics of the grass is that it can
grow insoilswitha relatively lowphosphorus (P) status. Bottlebrush
grass is naturally found inwarm and arid areas. It grows in regions
with an annual rainfall of between 250mm - 650mm.
Management and utilisation
Bottle brush grass should be established on a weed free and fine
compacted seedbed. If this species is to be planted on acidic soil,
the soil’s pHneeds tobe increased to 6,5byusing agricultural lime.
Soils with a low P content will require approximately 150 kg/ha -
200 kg/ha of superphosphate before the establishment of the
species. Bottle brush grass is however adapted to soils with a low
P content; this recommendation is to ensure a higher production.
Thebest time for seedingbottlebrushgrass is at theendof January
till the end of February. However, if weeds do not pose any threat
to establishment, earlier planting is a viable option. In this context
it can be said that this grasses’ seedlings are very competitive
with weed species compared to the seedlings of grasses such as
Cenchrus ciliaris
,
Digitaria eriantha
and
Panicummaximum
.
In general it is recommended that the best time for establishment is
the timeof the yearwhen the rainfall ismost reliable.
It is advisable that freshly harvested seed should rather not be
planted, but that the seed is allowed to ripen/mature for at least
nine to twelvemonths before planting. This species can be planted
at rates of 3 kg/ha - 5 kg/ha in 1,5m - 0,75m rows and up to 7 kg/ha
for broadcast seeding.
Good stands of bottle brush grass have been achieved in the
Molopo region at seeding rates of 2,5 kg/ha to 14 kg/ha. For optimal
stand densities, good quality seed at 5 kg/ha for row plantings
and 7 kg/ha to 9 kg/ha for broadcast seeding is recommended.
Row plantings are preferred in drier regions to make better use of
soilmoisture.
As previously mentioned, bottle brush grass has the ability to
surviveon soilswith low levels of P, but it is however recommended
tomaintain a soil P content of nothing lower than 12mg P/kg of soil
for highproduction.
Nitrogen (N) applications will mainly be determined by rainfall
received. During the dry season, N applications should be in the
order of 20 kg N/ha to be economical. If the rainfall is higher than
450 mm per year, an application rate of 75 kg/ha can be used to-
getherwith 25 kgP/ha and 50 kgK/ha.
Research in the Free State has shown that it is not only themacro-
nutrients that are important in this pasture species production, but
also themicro-nutrients.This research indicated that thezinccontent
can be lower than the grazing animal requires. This situation, like
many other cases withmicro-nutrient deficiencies, can be ascribed
WAYNE TRUTER,
University of Pretoria,
CHRISDANNHAUSER,
Grass SA,
HENDRIKSMITH,
Grain SA and
GERRIE TRYTSMAN,
ARC-Animal Production Institute
Integrated cropandpasture-based
livestockproduction systems
–Part 7
AGRICULTURE
Conservat ion
Series
September 2014
106
