Business Rural Autumn 2023

98 | Mainland minerals on fine particle use Using fine particle, or the non-water-soluble granular fertiliser should be encouraged, according to Mainland Minerals Southern. Virginia Wright Mainland Minerals Southern supply custommade fertiliser mixes to farms south of the Waitaki River combining with two other regional suppliers to be the third biggest supplier of fertiliser in the country. It’s a family business run by Murray and Aimee Cockburn. With a strong emphasis on both science and sustainability they have worked closely with respected soil scientist Dr. Tim Jenkins researching the real-world outcomes of applying their signature, bespoke, fine-particle fertiliser mixes. Through research trials and analysis they worked out that using a combination of both fine particle and granular fertiliser, at different times dictated by soil testing, offers a sustainable, economically viable solution to fertiliser needs over both the short and the long term. They recognised a pattern in some regions where using only fine particle fertiliser saw a drop in phosphorus levels over the longer term, explains Murray, as what he describes as the ‘nutrient pantry’ was depleted. “We found we needed to keep the pantry sufficiently full with phosphorus and potassium to maximise the gains brought by the other nutrients and get the biology of the soil working.” One big aspect of the sustainable side of it is their use specifically of granular di-calcium phosphate, when it’s needed, in their fine particle applications. “It’s fully non-water soluble so it’s not at risk of leaching and 90% of it is available to the plants from the first week to a month. As opposed to superphosphate 090 which is 87% water soluble so basically when it gets wet it turns to a liquid so it’s at risk of leaching below the root zone and getting into the waterways. Phosphorus and nitrogen are the two key components for RURAL SERVICES » Mainland Minerals - Southern making algae,” says Murray. From the research Murray’s been part of, selfinterest not-withstanding, he’s surprised that New Zealand farming continues to prefer superphosphate as their number one fertiliser. “Our factories bring in the parent material and they put sulphuric acid with it to make superphosphate, then we put this water-soluble phosphorus onto all sorts of soil types. Some are fine because the soil has the ability to hold onto that fertiliser once it turns liquid, it’s called phosphate retention, so it’s not as much at risk of leaching; but when you put it on glacial soils through much of Central Otago, or sandy river soils, they’re no good at holding onto the phosphorus or the fully water soluble sulfate sulphur. First, the farmer misses out on a lot of the investment because if there’s a big rainfall it flushes through the soil below the root system and it’s gone, and second, it’s potentially going into those waterways. One of my biggest goals at the moment is to try and convert these farmers into using fine particle, or the non-water-soluble granular fertiliser, that we sell because I believe it’s a really good legacy to reduce what’s going into the lakes and rivers so we’re not causing pollution for the long term. I don’t believe using super-phosphate is the smartest thing for New Zealand’s soils and environment in the long term and the only countries where it’s still the number one fertiliser are us and Brazil.” In his former life as a structural engineer geology was a big part of Murray’s work, understanding soils came with the territory and problem solving the nature of the business. When he bought into the fertiliser industry with his wife and father-in-law he set about learning what he could about the industry and New Zealand’s soils. He quickly worked out that we needed to be ahead of the curve when it came to sustainability. That was his drive behind the fine-tuning of their application of fine-particle fertiliser, to be used as a foliar feed, which they combine with detailed soil testing to address specific needs, replenishing nutrients and stimulating soil biology at the same time. They’re working closely with farms stretching 50 kilometres along the banks of Lake Wakatipu from the Crown Terrace to just south of Kingston as well as farms in various catchments around Lake Wanaka. “That to me is a legacy, we’re looking after those lakes for our grandchildren,” says Murray. From the farmers’ point of view there’s nothing 25 Avon St, Gore | Proprieter ALLAN RIEPMA - 03 208 6380 For all your Machining & Welding Requirements EM will improve yield and performance in agriculture through enhancing soil biological activity and fertiliser inputs. · Improve Soil Health and Performance · Improve Yield · Enhance Fertiliser Inputs · Improve Root Structure · Improve Germination · Reduce Soil Compaction · Improve Organic Matter Breakdown P. 03 374 6323 | E. paul@emnz.co.nz www.emnz.com DYNAMIC MAINTENANCE LTD - PH 03 235 8833 22 Lorneville-Wallacetown Highway, Invercargill PROUD TO SUPPORT MAINLAND MINERALS Compressed Air and Water Engineers to lose and everything to gain according to at least one set of figures quoted by Murray. After 10 years of working with a dairy farm in Otautau in Central Southland, who are not a big user of nitrogen, they have increased their milk solids from around 900 kgs per hectare to around 1400kgs, with fewer animals. Murray would love to see Mainland Southern Minerals’ research picked up and developed further by the big players who don’t yet seem to be interested in changing their paradigm, but who could help change the future of sustainable farming in New Zealand.

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