Rotation combats costly nematode issue
Author: Sarah Jeffrey | Date: 27 Aug 2015
The move to a cane/peanut crop rotation has dramatically changed the nature of farming for Bundaberg district growers Neville and Jason Loeskow over the past 20 years.
Not only has it generated substantial improvements in crop productivity, input costs for the management of nematodes have also been slashed since the mid-1990s delivering savings of nearly $200,000 a year.
The Loeskows purchased the 1600 hectare property in the 1960s and operated it as a cattle enterprise before expanding into irrigated cane production during the 1970s and 1980s.
However by the 1990s they had begun incorporating peanuts as a rotational break crop to help control rapidly escalating root lesion (Pratylenchus zeae) and root-knot (Meloidogyne spp) nematode populations.
In the past, the family regularly applied nematicide at a cost of approximately $2 per tonne of cane produced but the introduction of a non-host crop like peanuts into the farming system has meant that the costly nematicide applications are no longer required.
While that alone has heralded significant improvements to crop gross margins, Jason Loeskow said there have been additional agronomic, yield and operational benefits of shifting to a legume rotation.
“On this marginal soil, it’s very important to incorporate a rotation crop like peanuts - it has increased our cane yields to where we expect an autumn planted crop to average 140 tonnes per ha, the first ratoon about 120t/ha and the second at about 100t/ha,” Mr Loeskow said.
“With no rotation, we had 80t/ha, 60t/ha and 40t/ha on the initial, first ratoon and second ratoon respectively. This was largely due to no legume, no rotation, no break crop.
“It has also given us a wider range of options for weed control and enables us to keep our workforce employed for the full 12 months of the year as the peanut season fits into the quieter time of year for the sugarcane.”
Department of Agriculture and Fisheries (DAF) senior agronomist and project leader of the Grains Research and Development Corporation (GRDC) funded Coastal Solutions Group, Neil Halpin, said nematode survey work had highlighted the severity and extent of the issue in the Bundaberg cropping region and therefore the need for growers to consider a long term rotational farming system.
“Survey work undertaken by Dr Graham Stirling from Biological Crop Protection found that plant parasitic nematodes were a much larger issue in cane growing regions than previously thought with Pratylenchus zeae found in every paddock sampled in the central coastal region of Queensland,” Mr Halpin said.
“Local trial work has shown that in a monoculture, six beneficial nematodes exist for every one plant parasitic nematode.
“But after a rotation, that ratio changes from 136 beneficial nematodes for every one plant parasitic nematode, clearly demonstrating the enormous benefits of a well-planned and well-executed rotational cropping program to soil biology, soil health and plant production.
“The challenge remains to further improve soil health; to build suppression to adverse biology. Crop rotation, controlling traffic, retaining crop residues and reducing tillage are our current ‘tools of choice’ in managing the nematode threat in coastal sugar-based farming systems.”
Elise McKinna, DAF Media & Communication Officer
07 3087 8576
Sarah Jeffrey, Senior Consultant Cox Inall Communications