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FARM SERVICES | 3 April 2009

Soil tests pay off at Croppa Creek

Paddy Coleman decided to take Sharon O’Keeffe’s advice on fertiliser rates for his 2009 winter wheat and barley crops, and why wouldn’t he?

Deep soil testing last year allowed the Landmark senior agronomist from Croppa Creek to recommend fertiliser at nutrition levels appropriate to targeted yields, and Mr Coleman reaped the rewards with 3.2 t/ha of wheat at an APH-winning 13.8% protein.

Yes, Mr Coleman says, he is “pretty happy” to keep discussing his cropping options with Ms O’Keefe, and Ms O’Keefe herself is also “pretty happy” with the quality of the business relationship with Mr Coleman.

That advice is backed by Landmark’s NutriWise program that uses laboratories that are accredited by the Australasian Soil and Plant Analysis Council (ASPAC) accredited laboratories and helps qualified agronomists make accurate and economic fertiliser and soil ameliorant recommendations for target crop yields.

Landmark Farm Services agronomists use NutriWise and other decision support software like the whole farm planner PaddockWise to deliver farm and paddock planning, soil testing, advice on variety and fertiliser selection, weed, disease and insect identification and control, water-use efficiency, natural resource management and precision farming.

Mr Coleman and his farm manager Jim Klowss have tested their soils for about 10 years – deciding fertiliser application rates in line with the district average recommended by agronomists and other farmers – and 2008 was the year they went into serious deep testing with Landmark and Ms O’Keeffe.

After soil testing, the 2009 wheat will receive Mr Coleman’s usual 50 kg/ha of starter fertiliser at planting time; pre-plant urea – followed by Kelly discs – has been applied already at 70 to 120 kgs/ha, “where our soil tests show the crop will give the most bang for a buck” according to Ms O’Keeffe.

“The aim is to spend fertiliser dollars where the yield will deliver the biggest response, and we decide where that is with deep soil testing. Tests of the top 10 centimetres of soil really aren’t much of an indication,” she said.

“Mr Coleman has just bought another block of country, and our deep soil testing there has shown it is likely to have some sub-soil constraints – notably sodicity – at depth and that has caused nutrient bulges where the roots physically can’t access the stored nitrogen

“Our deeper soil tests showed some other areas where an application of phosphorus would be beneficial upfront, but sulphur levels are OK at depth.”

Ideally Ms O’Keefe prefers to split nitrogen application in wheat – half the rate pre-plant and the other half top dressed once the season has established and realistic yield targets can be set– but Mr Coleman argues that the in-crop application cannot be managed as well as in pre-plant, with following rain necessary to ensure the nutrient benefit from the urea.

He does agree that Incitec’s Green Urea, which is protected from volatilisation loss for several weeks without rain, might work better in a split nitrogen application.

Mr Coleman hopes prices for zinc, sulphur and phosphorus fertilisers will continue to fall, to the point where they are economic to use again.

He knows they are essential to the long-term health of his soil, and that what is not applied when prices are high still has to be paid back in the long run.

The Blackjack aggregation of properties – 2500 ha with a bit more than 1300 of them arable – will have about 1000 ha under winter crop in 2009.

For the first time 160 ha will go under chickpeas – rocky country previously persuading Mr Coleman and Mr Klowss that, while the peas would grow well, they could be difficult to harvest – and there are 160 ha under Grout variety feed barley.

Mr Coleman says he eases off the nitrogen fertiliser with barley, experience having taught him that high levels of N will produce a big biomass that will yield pinched grain when there’s a dry end to the season.

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