SEMI-ARID GRAINS PRODUCTION
Grains production in the semiarid, rain fed areas of Australia has been revolutionised
through dramatically improved (soil) water use efficiency, leading to both more
guaranteed harvests as well as greater crop frequency (up to five harvestable crops in a 2
year period have been reported). Achievement came from the cumulative effect and
synergy of 3 CA practices (zero till, controlled traffic and rotation/cover crops) in a
farmer-led, simplified cropping system. Zero till not only ensured metal-on-soil
compaction was greatly minimised but also that tractor size, use of tractors and diesel
consumption have all decreased with associated reductions in costs, fossil fuel use and
potential for global warming. Further, controlled traffic (with all tyres running in
permanent, fixed tracks) has ensured eradication of wheel-induced compaction in the
crop-growing zones. Adding to these positive effects, combinations of commercial crops
and cover/rotation crops have ensured a wide spectrum of soil benefits: organic matter
enrichment for increased soil stability, cover for erosion minimisation, continuous food
supply for earthworms (and the less visible, vital microbiological activity). Real
outcomes include enhanced organic matter incorporation, fertility enrichment in casts,
and continuous macropores for maximum soil profile refill and reduced surface water
ponding (reducing potential for both evaporative water loss and erosion). The working
harmony of the three CA elements has not only provided more assured, long term
sustainability but also as one farmer said, “ has made farming so much easier as the soil
response (to cropping) has become much more predictable”.