easily establish andgrowonpoor quality soils, it alsohas the ability
to utilise nutrients more efficiently. This is advantageous, since it
provides good quality pasture at a lower cost, because it uses
nutrients very efficientlywhile also restoring soil structure.
Animal production aspects
Weeping lovegrass can provide a grazing capacity of 1,5 MLU/ha -
4,0 MLU/ha. Other than the amount of available forage the species
provide, thenutrient valuewill play anessential role in thepalatability
of thepastureand theamountofpasture intakeby theanimal.Nitrogen
fertiliser can therefore have a positive effect on the digestibility of
the pasture and more importantly the crude protein (CP) content.
According toworkalreadyconductedbyRethman in the1980’s, it has
been shown that the crudeprotein can reach levels of up to 19%with
240 kgN/ha.
In addition to the nutritional value weeping lovegrass can provide
(with good nutrient management), the particular growth stage has
an influence on the quality of the material ingested as well. When
hay is produced in the pipe stage (that is just before the onset of the
reproductive stagewhen the inflorescencedevelops), better livestock
production can be expected. In terms of average daily gains (ADG),
researchhas shown that anythingbetween 240g/day - 650g/day can
be achievedon average. In total, as high as 750 kg/ha - 1 000 kg/haof
animalweight gaincanoccur over anentiregrowing season.
Grain crop production
After establishing a typical ley crop system using weeping love-
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 the soil surface providing cover that limits erosion and enhances
water infiltration aswell as 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 crop planned after pasture, will influence
the timing of removal of the pasture. Reliable and timely seasonal
rainfall forecasts may assist in this planning. Following the pasture
phase, grain crop yieldwill be restrictedunless the soil water profile
is replenished. After removing thepasture,weeds in the fallowmust
be controlled to conserve soil water tomaximise the benefit of the
ley. A suitable no-till planter shouldbe used toplant 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
Asa low-inputpasturecrop,weeping lovegrasscanplayasignificant
role in conservation agriculture. If a croplandhas been continuously
tilled for many years and the health of the soil has degraded, this
species can be planted very successfully, restoring the soil and
providing good quality hay or grazing at the same time. The dual
benefit of soil rehabilitation, together with livestock production
returns, proves the long-term value of pasture ley cropping in
conservation agriculture.
For more information, contact Dr Wayne Truter at
wayne.truter@
up.ac.za
,ProfChrisDannhauserat
DrHendrik
Smith at
and Mr Gerrie Trytsman at
Weeping lovegrass (
oulandsgras
).
51
April 2014
