Wednesday, 14 October 2015

Serious savings from whole-farm soil testing


Whole-farm soil testing saves Taranaki farmer Hayden Lawrence about $15,000 on fertiliser each year.

Hayden, who farms in equity partnership with his wife Alecia and parents in Taranaki, began whole-farm soil testing seven years ago. To date, he has reaped about $90,000 in savings and has increased pasture production from 14.5  to 18.6 tonnes per hectare on their 97ha property.

  • The Lawrences milk a maximum of 240 cows on an 85ha milking platform, using their hill country block to graze heifers.
  • They follow an 18-month cropping rotation that sees paddocks planted into silage, oats, chicory, and then into pasture.
  • They are trialling a three-year calving programme where cows will be milked for 450 days and calved twice.

Research from Dairy NZ shows the additional days of milking could increase milk yield and potentially decrease animal health issues by reducing calving. As part of the trial, they are also growing fodder beet and maize.

Hayden says whole-farm testing is a “no brainer” for the business. On average, it saves $162/ha from a blanket fertiliser application approach.

For us to whole-farm soil test 50 paddocks costs $2,500. We had been spending about $40,000 a year but that’s down to about $13,000 a year.

When we started, Dr Ants Roberts (Ravensdown’s Chief Scientific Officer) came down and did up a plan, which we still use. We have seven fertiliser mixes and one of those is no application.

Analytical Research Laboratories (ARL) analyses the annual soil samples, taken from GPS transects for accuracy, and uploads the results to My Ravensdown, our secure online farm-management tool. Based on the results, Hayden orders fertiliser and plans spreading with our joint venture Spreading Sandford, who collect and spread the various mixes.

The whole-farm testing results haven’t been hugely surprising, but Hayden has noticed how various crops and management programmes affect nutrient levels. It’s also been beneficial for knowing when they can mine nutrients and when they need to top them up.

“We were advised that on our Taranaki ash soils, the farm probably wouldn’t need large quantities of superphosphate. But after two years we saw sulphur levels start to bottom out. We’ve easily addressed this by using sulphur mixes combined into our last nitrogen application in autumn and our first nitrogen application in spring,” Hayden says.

ARL Technical Director Dr Hendrik Venter says the analysis of soil test results for samples submitted during 2014 showed that for pH, Olsen P, potassium, magnesium and sulphate-sulphur, there was a significant number testing above and below recommended science-based optimum ranges.

“A soil test will help ensure the application of enough fertiliser to meet the requirements of the crop, while taking advantage of the nutrients already present in the soil. Soil testing is one of the best management practices to achieve maximum production and with fertiliser being one of the largest input costs for farms. Flying blind is never advisable!,” Hendrik says.