Home' Partners : Partners: The dryland agriculture revolution Contents 12
winter 2013 PArtnerS
BY MeLISSA MArInO
onservation agriculture (CA) is not
a ‘one-size-fits-all’ approach. while
its key principles of minimal soil
disturbance, permanent soil cover
and crop rotations remain consistent,
the methods used to realise them can vary.
in Pakistan, ACiAr-funded CA research has
centred on the use of permanent raised beds.
this is largely through 10 years of work in the
north-west, near Peshawar, led by western
Australian soil physicist Greg Hamilton.
in this part of Pakistan, maize–wheat crop
rotation systems are common, as distinct from
the rice–wheat and cotton–wheat systems
found throughout the Punjab region, which
covers Pakistan’s centre and south, as well as
the north of india. As the work concentrated on
maize–wheat, most of the results and the best
outcomes are from this system.
Mr Hamilton says results from two trial
sites and several hundred hectares of farmer
adoption in Mardan, north-east of Peshawar—
where permanent raised beds using furrow
irrigation are used to replace flooding
irrigation—found many advantages. these led
not only to an improved environment but also
a greater overall profit.
From 1999 to 2010, through two
ACiAr projects interspersed with Pakistani
government funding over 24 cropping
seasons, farmers across the Mardan district
achieved an average increase in gross margin
profits of 23–25%, Mr Hamilton says. this is due
to several factors.
First, a raised-bed system requires less
seedbed preparation compared with flood
irrigation, replacing three or four separate
field operations with one or two. this provides
significant cost savings in labour, fuel and
herbicides. Labour and herbicide use were
also reduced because the system aids weed
suppression. raised beds have 30–50% fewer
weeds than traditional systems, he says.
water savings too were significant, with
30–50% less water used. And deeper and
improved root zones, created by a deep-blade
loosening and furrow making, led to increased
yields. there was a 10–20% yield increase in
wheat and maize yields grew by 30–50%, Mr
Dr Christian roth, who was ACiAr research
program manager for land and water resources
at the time of the project, says the raised beds
worked well for maize–wheat crop rotations,
bringing the dual benefit of major water
savings and improved soil structure.
Mr Hamilton says healthier soils improve
water usage. “Over three or four years, soils
developed that were much more stable to
wetting and irrigation efficiency improved
dramatically,” he says.
Soils in Pakistan’s north-west have been
degraded over centuries due to over-cultivation
and flood irrigation. “excessive cultivation
removes all the root material and soil organisms
that feed off the root material, making the
soil less physically stable and fertile,” he says.
“Soils in this condition fall apart when irrigation
water is applied and the water is far less able to
penetrate the soil.”
improved farming systems are urgently
needed because Pakistan is one of the most
water-insecure countries in the world and
highly dependent on irrigated systems for
food. Over time, cultivated land has suffered
substantial productivity declines, which
have been estimated to be as high as 25% of
Mr Hamilton’s project replaced flood irrigation
with raised beds and furrow irrigation. the
system uses two machines: a no-till disc seeder;
and a bed-former deep-blade loosener that
creates a bed in which the crop is grown and
excavates two furrows that align with tractor
wheels, creating a controlled-traffic environment.
this machinery applied CA principles,
ensuring there was minimal soil disturbance and
maximum root retention. But the precise nature
of the machinery is also one of the key reasons
that, despite the success of the trials, the system
has not been more broadly adopted.
while it is not complex, the machinery is
specific, Mr Hamilton says, and therefore has to
be specially manufactured. Australia provided
three sets of machinery for the trials and
ongoing use, but manufacturing and selling the
machines in Pakistan has proven problematic.
the machines, by local standards, were
expensive to produce and parts hard to
source. Attempts to adapt the machinery
using cheaper, more readily available materials
Raised beds prove their worth
The versatility of conservation agriculture was demonstrated in Pakistan, where trials
were found to vastly decrease hardships for wheat–maize croppers. But no progress is
ever truly possible without a broader social coalition willing to drive it.
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