Take More Care of Soil at Harvest

As printed in Grower February 2011

James Powrie and Dan Bloomer LandWISE Inc.

In November LandWISE, FAR and Horticulture NZ held combined field visits to 7 cropping farms.  Visual soil assessments were performed at a range of sites and discussions held about what was seen.

Each farm is experiencing common challenges with soil quality.  All of the farmers visited want more soil quality because of what it means for the future of their operation…and almost all are getting less.  When we say less… digging soil from under a fence shows where the soil has come from, or its natural state.  When this is compared to the cropped soil, there is always a difference.  Often compaction damage is seen as big hard lumps with plant roots growing around their edges. Virtual rocks.

Farmers wanting to move their soil back toward this state have a range of options.
Reduce the use of powered implements –  Powered implements use PTO power to turn a tool at speed.  Soil structure is shattered at point of impact, rather than a natural line, worms and other life are destroyed and the natural flow pathways and porosity are interrupted. Depending on severity, full destruction of soil structure can result.  Often the progressively damaged structure requires increasing use of powered implements to create tilth.

Reduced traffic – Any practical mechanised system involves field traffic and compaction of soil, usually by wheels. Wheels cause soil damage, but this can be limited to a small proportion of field area by restricting all heavy wheels to permanent traffic lanes. Adoption in NZ and other countries has demonstrated the effectiveness and practicability of Controlled Traffic Farming (CTF) systems in very different cropping environments.  Less trafficking means less remedial tillage is required to remove compaction and this can mean fuel savings and fewer operations.

Comparisons between CTF and conventional “random traffic” cropping systems in NZ are also showing improvements in soil quality, crop performance, time savings and a range of other gains.  Data from extensive grain production systems in Australia indicate that CTF could provide a major reduction in cropping emissions and massive improvements in hydrology.  CTF can improve productivity, and all measures of sustainability; it also overcomes some important constraints to the adoption of conservation agriculture.

As precise guidance becomes progressively cheaper, machine system width compatibility remains the only real barrier to a significant improvement in food security and the environmental footprint of cropping.  Imagined barriers can include tradition, stubbornness or resistance to change.

If soil is recognised as a primary asset on the farm and improvement a goal, then the cost is justified as an investment in the future.  It may be easier to make changes than you expect.  Some changes can create immediate improvements and savings.  With the urgency of better soil care becoming clear, be sure its not rocks in your head causing the rocks in your paddocks.

For more information on how farmers in NZ are making these changes and support with yours, talk to James Powrie (LandWISE) or Dan Bloomer.. Funding for this work has come from the Sustainable Farming Fund ‘Advanced Farming Systems’ and ‘Holding it Together’ programs.

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