FEATURE
Conservation
Agriculture
By Givemore Ndlezane, Agricultural
crop and livestock extension officer
([email protected])
C
onservation Agriculture is a
farming system that promotes
maintenance of a permanent soil
cover, minimum soil disturbance (i.e.
no tillage), and diversification of plant
species.
It enhances biodiversity and natural
biological processes above and below
the ground surface, which contribute
to increased water and nutrient
use efficiency and to improved and
sustained crop production.
The principles of conservation
agriculture principles could be applied
to all agricultural lands and practiced in
all agro-ecological zones.
It entails optimum usage of
agrochemicals, organic and inorganic
fertilisers in ways and quantities that do
not interfere with, or disrupt biological
processes, in addition minimizing
or totally eliminating mechanical
disturbance to the soil.
Conservation agriculture (CA) facilitates
good agronomy, such as timely
operations, and improves overall
agricultural land using both irrigation
and rain-fed production.
It counters the concept of soil tillage/
ploughing prior to planting, additionally
marking it as being responsible for
destruction of soil organic matter, a
crucial element for the stabilization of
soil structure.
It is worthy to note that a soil left
without tilling for long allows crops
36 |November - December 2018
residues/mulch to remain on the
soil surface, as such protecting
the soil from rainfall, heat from
the sun and wind. It also stabilizes
temperature and moisture which
becomes conducive for beneficial
small and large organisms that help
in decomposition of the mulch for
stabilizing the soil structure.
Soils under conservation agriculture
have significantly higher water
infiltration capacities, with high
reduction in surface runoff that
causes soil erosion.
PRINCIPLES OF CONSERVATION
AGRICULTURE
Minimum mechanical soil
disturbance
• Direct seeding or planting
Direct seeding involves growing
crops without mechanical seedbed
preparation and with minimal soil
disturbance since the harvest of the
previous crop. The term direct seeding
is understood in CA systems as
synonymous with no-till farming, zero
tillage, no-tillage, direct drilling, etc.
Planting refers to the precise placing
of large seeds (maize and beans for
example); whereas seeding usually
refers to a continuous flow of seed as
in the case of small cereals (wheat and
barley for example).
The equipment penetrates the soil
cover, opens a seeding slot and places
the seed into that slot. The size of
the seed slot and the associated
movement of soil are to be kept at the
absolute minimum possible. Ideally
the seed slot is completely covered
by mulch again after seeding and no
loose soil should be visible on the
surface.