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t
his article is the 16th in a series of articles highlighting a
specific pasture crop species that can play an imperative
role in conservation agriculture (CA) based crop-pasture
rotations. Besides improving the physical, chemical, hydro-
logical 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 to identify a pasture species fulfilling the require-
ments of a dual purpose crop, i.e. for livestock fodder and/or soil
restoration. This article focuses on a perennial pasture commonly
used to improve soil conditions and to provide a good grazing for
cattle and especially sheep.
Paspalum notatum
(Bahiagrass)
Bahiagrass is a summer growing perennial grass that develops
stolons (above-ground stems) and rhizomes (below-ground stems).
Reproduction takes place by seed, and bahiagrass spreads vegeta-
tively by short, heavy stolons.
Genetically, there are two types or two ploidy levels found in this
species that are cultivated: Diploids and tetraploids. This species
is originally from South America and is well-adapted to coastal
areas and plains. It establishes well in sandy soils with low water
retention and low fertility, and tolerates drought, sporadic flooding,
and continuous grazing.
Agro-ecological distribution
Bahiagrass is best adapted to sandy loams and tolerates low
fertility and low pH. It grows well on soils with acidic pH from 4,5 to
6,5 and the optimal soil pH is 5,5. At a pH greater than 6,5 the grass
shows chlorosis and stunted growth.
It survives well on soils that are susceptible to drought, where it
presents a more open stand to compensate for the low moisture
available. Bahiagrass grows vigorously under high temperatures
and when day lengths are long, and herbage production is greatest
from October to April.
More than 85% of the production occurs during the six warmest
months (October through to March). The most popular cultivars are
Pensacola, Tifton 9, TifQuik, and UF-Riata. These cultivars are dip-
loid, where Paraguay, Argentine, and "common” are tetraploids.
Management and utilisation
Bahiagrass is established by planting seed. An area where bahia-
grass is most likely to grow is on soils with good soil moisture
and which are well-drained. It is best to establish this species in
November. However, if irrigation is available, bahiagrass can be
planted as early as September.
It is essential to control weeds first before planting, since seed-
lings grow slowly, but once seedlings have emerged, apply fertiliser
following soil analysis recommendations. When seeding bahia-
grass, never seed too deep, and use sufficient seed.
Broadcast seeding rates can vary between 20 kg/ha - 25 kg/ha.
Use the correct seeding rate as this will result in the stand closing
quicker, and the opportunity for weeds to fill in the open spaces
will be minimised. After seeding, consolidate the soil with a roller to
seal the moisture in the soil.
Light fertilisation of bahiagrass will generally be necessary within
seven to ten days after seedling emergence. The initial application
should consist of 65 kg nitrogen (N)/ha, all of the recommended
phosphorus (P), and 50% of the recommended potassium (K).
Approximately 40 to 50 days after the initial application, an addi-
tional 100 kg of N and the remaining K should be applied. If manure
or bio solids are used as the main source of nutrients, apply the
entire annual application at one time after the plants are large
enough to withstand physical damage from the application. Well-
fertilised plants will form a dense stand in 60 to 90 days, at which
time a light grazing or mowing can be done.
The weed control in bahiagrass at seedling stage needs to be
done mechanically by mowing. From emergence to approximately
15 cm in height (seedling stage), bahiagrass does not tolerate most
herbicides. Bahiagrass seedlings are susceptible to phenoxy-type
herbicides (2,4-D, Dicamba and others), and they should not be ap-
plied until seedlings are at least 15 cm tall.
WAYNE TRUTER,
University of Pretoria,
CHRIS DANNHAUSER,
Grass SA,
HENDRIK SMITH,
Grain SA and
GERRIE TRYTSMAN,
ARC-Animal Production Institute
Integrated crop and pasture-based
livestock production systems
– Part 16
AGRICULTURE
Conservat ion
Series
Julie 2015
68
ON FARM LEVEL
Conservation agriculture