Free fertiliser – up to 200 kg of nitrogen per ha, every year. Energy rich, delicious grazing. Higher animal production.

White clover has a lot to give. But unless you choose carefully, there’s a risk this autumn neither you nor your animals will get the full benefit of this hero legume.

That’s because some seed mixes for pasture renewal are being sold with old, outdated or untested clover seed to keep costs down.

Given the big difference in performance between the latest clovers, and a common like Huia, which dates back to the 1950s, it’s well worth checking exactly what your mix contains before sowing.

“This is really important,” says pasture specialist Graham Kerr, “as you could be missing out on a lot of value.”

Ryegrass dominates most seed mixes sold for pasture renewal, to the point where farmers often order seed by the name of their preferred ryegrass. A good example is you asking your supplier for a ‘Maxsyn mix’.

Graham says sowing the right seed, of known provenance and quality, is key to getting the best possible result from any new pasture.

“White clover is the powerhouse of New Zealand pastures, and just like ryegrasses, not all clovers are equal. Far from it, in some cases. That means we need to pay just as much attention to exactly which white clover we’re sowing as we do to particular ryegrasses.”

How can something that only makes up a small portion of a seed mix be so important?

“Just ask your animals!” Graham says.

He’s only partly joking – sheep, beef cattle and cows love clover, and thrive on it, so the more you have in your pastures, the happier they will be.

In summer, when ryegrass goes to seed and loses quality, lambs grazing clover will gain 100 grams per day more than those grazing grass, and dairy cows will produce 30% more milksolids per kg of dry matter.

That’s not all, however. Clover fixes nitrogen out of the air, at around 25 kg nitrogen per ha for every tonne of dry matter grown.

(In fact, prior to widespread uptake of synthetic nitrogen in the 1990s, NZ pastoral farming was almost entirely reliant on clover to fix nitrogen.)

So again, the more clover you grow, the more nitrogen enters your system, naturally, sustainably and at no cost.

“This is a big win for the environment, too. Manufacturing nitrogen fertiliser, and transporting it to your farm, produces a lot more greenhouse gas emissions than having clover do the manufacturing for you, in your own paddocks,” Graham says

Potential gains in efficiency and production are significant. Research has shown pastures sown with modern white clovers produces up to 4.4-5.4 tonnes of extra dry matter per hectare, per year.

The key point here is ‘modern’. Plant breeders have made big gains in clover yield in recent years.

All you have to do is compare the yield of Apex with Huia.

“We’re talking about a difference in growth of approximately 36% over 12 months!” Graham says.

“In other words, all our clovers - Apex, Weka, Kotuku - are miles ahead. If you think about it in terms of animal genetics, growing Huia is a bit like using a bull or a ram from the 1960s. Why would you do that when today’s sires are so much more productive?”

Modern clovers have also been bred for faster establishment, increased persistence, and better tolerance to clover root weevil, he says.

“On the face of it, you might save $30-40 per ha on a ‘Maxsyn mix’ that includes unknown clovers.

“But when you factor in the risk of lower clover yield, and the opportunity cost of not only fixing less nitrogen, but producing less milk or meat than you might otherwise, cheap clover seed is a big cost.”

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