Soil tips for big savings

WITH fertiliser prices almost doubling, farming operations are looking at ways to be more efficient with their fertiliser inputs with one dairy project showing there could be savings of up to 20 per cent.

Luke Taylor, principal consultant from AgAssist, along with Bill Cotching and Ross Corkery have been working on a research project funded by Dairy Australia, Tasmanian Institute of Agriculture and NRM South looking at spatial variation of soil nutrients within dairy pasture paddocks.

The results from the project found there was a wide variation of nutrient levels within the paddock, and from these findings some simple rules of thumb could be followed to improve fertiliser input efficiency with savings of up to 20 per cent.

“With the high fertiliser prices you can’t afford to be applying nutrients on paddocks or areas within the paddock which have elevated P and K levels as you simply won’t get a response,” Mr Taylor said.

In the project, eight paddocks under perennial pasture were sampled on six commercial dairy farms in Tasmania, on a grid with 32 to 40 topsoil samples points taken from each paddock at 0–100 mm depth.

The samples were analysed for soil pH and the plant available nutrients of phosphorus, potassium and sulfur.

Soil nutrient levels were highly variable within paddocks due to livestock concentration and fodder management.

“The project clearly showed that the phosphorus and potassium levels were high to extreme in the first 20 per cent of the paddock from the gateways in long-term dairy paddocks,” Mr Taylor said.
“This means there is a potential saving in most paddocks of up to 20 per cent in fertiliser cost if these areas are excluded from the fertiliser program.”

“Grid sampling like we did would be costly and would most likely not be viable, but following the simple rules from the findings will help improve nutrient efficiency.
“With the dairy operations it is a matter of being as efficient as possible with your fertiliser use.

“Cutting back too much will result is lost production but cutting back on the areas which don’t need fertiliser will maximise the efficiency of your fertiliser spend and reduce the risk of nutrient losses to the environment.
“Where effluent is being applied, the fertiliser rates need to be cut back or even excluded. The bigger the area that can be used for effluent the more potential there is to cut back on fertiliser inputs.”

For sheep and beef producers Mr Taylor offers a few tips.

“With current fertiliser prices nearly doubling, unfortunately it means if producers plan to spend a similar amount on fertiliser as they did last year they will only get half the tonnes,” he said.
“This means producers need to prioritise which paddocks to fertilise. The most obvious saving is to review your soil tests and not apply phosphorus or potassium on the paddocks with high levels.”

Mr Taylor said avoid applying fertiliser on high fertility areas within the paddock like stock camps.

“Any paddocks with recently sown pastures should be regarded as a priority to fertilise as it costs a lot to put them in and you need to look after them.
“You should also stick with the pasture renovation plans and apply capital P where required.

Skimping on this can be costly if it leads to poor establishment.

“Lime prices are relatively stable so use soil tests to identify paddocks which require lime, particularly newly sown pastures and pastures earmarked for renovation.”

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