Northern farming systems are becoming increasingly reliant on grain growers to assume the role of ‘soil custodians’ to preserve farmland productivity.
More than 100 growers and advisors attended a recent More Profit from Crop Nutrition (MPCN) workshop near Kingaroy to learn about soil nutrient management and its critical function in a healthy and profitable farming system.
The workshop was a collaborative effort between the Grains Research and Development Corporation’s (GRDC) MPCN initiative and the Inland Burnett Grower solution group and provided growers with best practice advice on nutrient removals, soil testing and fertiliser placement as well as research findings from local trials.
Department of Agriculture, Fisheries and Forestry (DAFF) researcher and project leader, Dr Kaara Klepper said the workshops reinforced that an “out of sight, out of mind” approach to soil management challenges had the potential to significantly impact the sustainability and profitability of farming, forage and livestock farming systems.
“Many growers are now realising that we have to replace nutrients that we have taken or are taking out,” Dr Klepper said.
“So it is extremely important to regularly measure existing soil nutrient levels and ensure that adequate amounts are being supplied to maintain production.”
Dr Klepper said many northern soils were depleted in phosphorus (P) in the 10 to 30cm layer even if starter fertilisers have routinely been applied with the seed.
“This occurs because the roots forage moisture and nutrients at depth and unlike nitrogen (N), nutrients like P and K don't move in the soil profile,” she said.
“Testing has shown that Potassium (K) reserves are very low in some cases and perhaps fertiliser application required.
“Sulfur (S) on the other hand can move like nitrogen in the soil and thus sampling to maximum soil depth is advised.
“It is critical for growers to remember that all nutrients need to be well supplied - if one nutrient is deficient money can be wasted applying other nutrients because there will be no yield increase.”
Workshop attendees were advised that nutrient testing needed to be conducted separately at appropriate frequencies – N testing should be carried out on a crop-by-crop basis, K and S levels should be checked regularly while P levels can be checked at 3 to 5 year intervals as long as the deeper layer is checked and growers use the Colwell and BSES methods.
Other topics discussed included the application of nutrients and in particular the widespread suitability of bagged fertiliser where growers have checked the analysis of nutrients and calculated the quantity required to correct any deficiencies indicated by soil tests.
The N benefits of rotating legume and cereal crops were covered during the workshops and growers were alerted to the fact that much of the N produced by the legume is removed in the grain.
“There can be some contribution from the left-over stubble however the key is to grow the biggest plant possible which will probably mean the application of P, K, S or zinc fertilisers but not N,” Dr Klepper said.
“Taking care with the seed inoculant is the key to helping the legume produce the ‘free’ nitrogen.
“Building the organic matter of the soil was also agreed to be a very valuable aim and practices that are beneficial to maintaining soil organic matter include the incorporation of a grass-legume pasture rotation into the cropping system, growing a large amount of stubble and retaining it, minimum or zero tillage, and adding manure or other organic materials.”
More information on any of these topics is available from the GRDC website www.grdc.com.au.
Caption: More than 100 growers and advisers from across the inland Burnett region attended the recent More Profit from Crop Nutrition workshop at Kingaroy.
Elise McKinna, DAFF Media & Communication Officer
07 3087 8576
Sarah Jeffrey, Senior Consultant Cox Inall Communications
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