20 / 44
Desember 2015
18
At the same time, with the use of
M. pruriens
, reductions in the dam-
age and mortality caused by Pythium, Rhizoctonia and Fusarium on
maize seedlings have been documented, probably due to the type
of organic matter that is incorporated into the soil, and the effects
of this on the soil’s microclimate and/or its allelopathic effects (Ver-
steeg & Koudokpon, 1990).
Management challenges
Although velvet bean is used to control weeds in agricultural set-
tings, it is an invasive species and can negatively impact on envi-
ronments outside of cultivation. Some agronomic disadvantages of
velvet bean include:
It is susceptible to burning during the dry season of the year,
especially when it is grown in areas that are managed by slash-
and-burn.
It is defoliated by some rodents.
It can attract certain sap sucking insects.
When a legume such as
M. pruriens
is grown in association or is
intercropped with maize, a reduction in maize yield often occurs dur-
ing the first cycle. The severity of such reduction depends on the
legume species as well as its density and management.
Soil nitrogen losses through leaching and volatilisation have been
recorded in research projects, because of the absence of a crop able
to absorb the nitrogen being released through decomposition – the
immobilisation of nitrogen at the same time when the crop has the
highest demand for this nutrient.
CONSERVATION AGRICULTURE
Animal production aspects
Despite velvet bean being such a useful forage crop, the seeds can
often be toxic to mammals, with reported cases in pigs. This fairly
high-protein fodder (greens and pods) can be eaten by most live-
stock, except pigs and chickens, since the seeds contain an anti-
nutritional factor that will retard the growth of non-ruminants.
Velvet bean in an early vegetative stage, looking promising.
Velvet bean in a late vegetative stage.
ON FARM LEVEL
Conservation agriculture