Precision mapping of soil ‘next step in sustainability’ – Timaru Herald, April 2014

A new generation of soil mapping technology is giving farmers insights into what lies beneath the surface of their paddocks.

Four South Canterbury farmers have imported a Veris MSP3 machine from the United States that combines electrical conductivity (EC) mapping of paddocks for soil texture, infra-red measurement of organic matter and constant sampling for soil pH. The machine is towed behind a tractor and takes takes 20-25 ph samples per hectare; and 150-250 soil texture and organic matter samples per ha, feeding the data back to an on-board computer.

Colin Hurst, who farms at Makikihi, in Waimate District said the end result was a precise picture of the soil’s composition.

Hurst said data from the Veris would help farmers fine-tune inputs, use nutrients more efficiently, and reduce the risk of environmental damage. “We can see soil characteristics and how they vary in greater detail than ever before, and in a format that will allow us to programme machines to make variable rate applications across paddocks. It will make us all the more environmentally sustainable.”

Soil mapping was significant for irrigation as well. “We can identify the at-risk soils for n leaching, and identify the soils where you can save irrigation water using precision irrigation.”

While Hurst and the other three farmers involved – Michael Tayler, Nick Ward and Hugh Wigley – are all cropping farmers, they believe the machine will be equally useful in other farming systems including dairy and livestock farms to improve pasture management. “Grass is a crop just like any other: it needs the right soil pH to maintain nutrient availability to plant and animal, and soil texture and organic matter content are major factors in determining soil water holding capacity, a key consideration in scheduling irrigation.”

Traditionally, fertiliser, lime and irrigation are applied at one rate across a paddock or even block of paddocks, determined by the average pH or soil water holding capacity. The farmers established Smart Ag Solutions to offer the soil sampling.

Operations manager Seaun Lovell uses the data collected in the paddock to create maps for clients. “The map shows precisely where your applications can do the most good. With GPS, this allows both the Veris, and the farmer’s machines to identify exactly where they are at any point in time, and apply the right amount of an input, be it fertiliser, lime or water.”

Components on the Veris include a sapphire window on an optic shoe that sends an infra-red beam 62cm into the soil to measure organic matter. The data is bounced back into the computer in the tractor cab. Discs beside the optic shoe carry electrodes that analyse soil texture up to 91cm down into the root zone.