Fert Options with Robin Boom Agronomic Advisory Services

Earlier this year I was invited by a Chilean-based fertiliser company called Bayovar Fosfato to present a series of talks to farmer groups, consultants, vets and agronomists there on the benefits of Reactive Phosphate Rock fertilisers.

Bayovar has its own phosphate mine in Peru in the Sechura desert, although the P content of this is lower than most RPR fertilisers, being around 7.5 per cent total P, but it is highly reactive at around 50 per cent Citric Solubility.

Ballance in New Zealand imported this product a couple of years ago and I was very happy to recommend it to clients because of its high reactivity, meaning it should all work over two to three years. It is far better than the BG4 product Ballance and Ravensdown have been selling to their clients the past 12 months which will take 20-30 years to fully work.

It is unfortunate that Ballance has not continued importing this Sechura as Bayovar had a contract with them to supply 80,000 tonnes, but only around 30,000 tonnes was ever purchased.

Bayovar also have the marketing rights for a 13 per cent P Sechura RPR in Chile which has a higher cadmium level than what is allowed here in New Zealand but still has excellent agronomic properties. The area Bayovar is based in Chile is around Osorno which is about 1000km south of Santiago on a similar latitude to Wellington and is right in the heart of the main Chilean dairying and beef-producing region.

Progressive farming

Progressive farmers over there have adopted a lot of New Zealand grazing management practices, use New Zealand pasture cultivars and with a similar climate and rainfall to what we have here, there is potential for them to produce as much per hectare as what we do. The soils in this region are volcanic-based, with deep topsoils, and most of it is flat or easy rolling in contour.

There is still quite a lot of land which is unfertilised and not well-managed which has huge potential. A big New Zealand based syndicate of farmers called Manuka currently farms 23,000ha milking more than 50,000 cows, and over the next few years hopes to grow to 40,000ha milking 100,000 cows.

Fonterra subsidiary Soprole is one of three main dairy companies operating there, the other two being Nestle and a local Chilean co-operative called Colun. Most of the dairy products and beef produced is for the local market, and the size and quality of the steaks are massive compared to what we are used to. I would imagine vegans would find dining there a bit of a challenge.

Double production

The average cow in Chile produces about double what our cows do, but there is a lot of grain and silage added into the diet. Since a lot of dairying supplies the fresh milk market, most farms milk all year round and are not seasonal. Labour efficiency is not great, and one farm I visited milking 400 cows had 17 staff on the farm.

Soil fertility advice, like here in New Zealand, is largely driven by companies selling products, with triple super being the main phosphate fertiliser used which is imported from China or Mexico. Sechura RPR is becoming increasingly popular through the efforts of Bayovar, as one of the main limiting factors to pasture production is aluminium toxicity which can be mitigated with the liming effect of RPR. Lime itself is very expensive in Chile since it needs to be trucked in from Argentina over the Andes.

Some farmers who used RPR commented that they observed a better response to RPR than Triple super, and I told them that is was probably not a P response they observed, but rather the liming value in reducing aluminium toxicity. Potassium and magnesium levels are generally okay, but sulphur and the trace elements boron and zinc are common deficiencies.

Length debate

Herbage testing is unfortunately very rare, and for soil tests, I had some interesting discussions as to how deep samples should be taken. The standard soil depth in Chile on pasture is 100mm which is the same depth the Australians use and which I also do, as I think it is better than the standard New Zealand depth of 75mm.

However the professor of soils at the local university there advocates 200mm sampling, and I had a lengthy debate with him on the pros and cons of this. Like in New Zealand, the Olsen P test is the standard phosphate test used, which is an issue for Bayovar as the Olsen P test does not pick up RPR very well, and they were interested in looking at other methods such as the Bray, Resin and Mehlich tests which are more suitable for acidic soils, and which other South American countries use.

Robin Boom CPAg, Member of the Institute of Professional Soil Scientists, phone 027 444 8764.