Fert Options with Robin Boom Agronomic Advisory Services

In 1994 an article in ‘Straight Furrow’ covered a sharemilker on a peat soil near Hamilton had been losing nearly 10 per cent of his herd for three years running from milk fever-related problems, between 1988-1990, in spite of giving his cows lots of magnesium.

I’d called on the farmer in spring-1990, a year after starting my soil advisory business, and told him the soil would be all out of balance and by correcting this, the problem would go away.

Like many farms at the time, they’d been using 30 per cent potassic super in the spring and 15 per cent potassic super in autumn. The farm owner agreed to let me try and sort the problem out, so long as the fertiliser bill was no more expensive than the conventional fertiliser they’d been using. After doing soil and herbage tests, which showed big imbalances, I recommended some burned lime ash at 2.5 tonne/ha as a cheap calcium and sulphur source, serpentine dust at 1 tonne/ha as a cheap magnesium source, potash, salt, boron, copper, manganese and selenium. No superphosphate was applied for the next three years and no more cows died from metabolic problems – and, the farm production lifted by 30 per cent, hence the reason for the article.

Metabolic problems

As a result of this article the manager of a large Maori-owned station contacted me, saying he had just lost around 50 breeding cows from metabolic problems. So I did comprehensive soil tests and herbage tests and again identified major imbalances.

However, the station was being overseen by a farm consultant who did not understand my American soil tests. As my recommendations were to apply some lime, magnesium, potassium and trace elements, which he took issue with, he sent my report to a soil scientist based at Ruakura, who dismissed my recommendations and told them all they should do was continue applying 15 per cent potassic super. Needless to say the farm consultant made certain this happened so my recommendation was never applied and the problem would have probably continued.

Over the years my relationships with farm consultants has generally been conflicting, because they tend to be just NPK boys. And unless phosphorus is measured by the Olsen P method, they don’t want to know – and I’m not a fan of too much nitrogen being applied, which they often promote. The exception is consultants who have come from a veterinary background – they generally understand the importance of having good calcium, magnesium, boron and other trace elements being applied for animal health and performance.

Déjà vu moment

Two months ago, I found myself having a déjà vu moment with the same farm consultant I’d hadthe issues with back in 1994. I’d done some soil and herbage tests with recommendations on a large sheep and beef property and recommended a triple super-based fertiliser mix with some trace elements. The trustees had asked this particular consultant to look at what was being applied, and consequently dismissed my tests and recommendations and got a fertiliser rep from one of the co-ops to do some more tests and apply a superphosphate-based mix.

After 30 years in the industry I’d like to think my knowledge of soil chemistry, as it relates to pasture production and animal health and performance, is second to none; and also my knowledge of all of the different fertilisers companies and their products. But not this farm consultant. He got a fert rep who has been on the scene for a fraction of this time and has a lot less experience and expertise than myself and who works for a superphosphate manufacturing company. The fertiliser applied worked out to be 15 per cent more expensive per unit of P on the ground than the triple super I was able to source from a private importer. The farm consultant charged for his services, gets inferior advice and costs the client tens of thousands of dollars for a more expensive fertiliser. All up, a lose-lose situation.

Robin Boom, CPAg, member of the Institute of Professional Soil Scientists. Ph: 0274 448764.