Cover Cropping

I developed this video with Stuart Smith, Senior Research Officer with Primary Industries. I asked him about the history of cover cropping in the North.

“We’ve been working to get adoption of cover crops for about 20 years because if you don’t use them the soil just slumps and loses its structure over the wet season or gets washed away. None of these soils have much structure to begin with, but if you leave them exposed over the wet, whatever structure exists is lost and it packs down like concrete. A cover crop can stop that happening.

“Entomologists have found that cover crops can reduce nematode numbers over the wet season and increase crop yield over the dry.

“I suppose 50% of farmers use cover cropping. In the Top End farmers tend to use sorghum and in Katherine they use millet. Both crops need to be slashed regularly during the wet season to stop in growing too much. If that happens, when its cut at the end of the wet there is too much trash on the ground that takes too long to break down.

Stuart received funding under the Australian Department of Agriculture, Fisheries and Forestry’s Action on the Ground Initiative. The initiative assists farmers and land managers to undertake on-farm trials of greenhouse gas abatement technologies, practices and management strategies.  

“Under our Action on the Ground project we want to demonstrate practices that reduce nitrous oxide emissions. Nitrous oxide is mainly produced when soil gets to about 60% water filled pore space, and when it’s hot. Cover crops absorb that nitrogen and so it’s used for plant grow rather than released into the atmosphere.”

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