Irrigation is key to cropping

DRIVING ACROSS the Canterbury plains is a dull business if you are a tourist. The bright lights and pleasant parks of Christchurch, the South Island“s capital, are behind you and the spectacular mountain scenery is still to come.

But if you are a farmer, or involved in agriculture, it is fascinating, with a kaleidoscope of crops and enterprises.

First shock to the UK agri-tourist is the irrigation – it seems to be everywhere, and a good deal on grass for the region”s booming dairy sector.

However, Canterbury remains the country”s granary, with 84% of New Zealand“s wheat production.

That is partly thanks to the dairy boom, driving demand for feed grain, straw and land for overwintering stock. But the emergence of a host of new, high-value crops to compete with cereals is also helping.

About half the plain has access to irrigation and water dictates crop choice.

On dry land (without irrigation) cereals and grass dominate with few companies offering contracts for anything else. But where water is available vegetable processors and seed-houses are almost climbing over each other to sign up skilled growers with good land.

One such grower is Eric Watson, from Wakanui, near Ashburton, Mid-Canterbury. This harvest he will combine 10 different seed crops across his 490ha (1210 acre) silty loam farm, ranging from traditional forages, such as ryegrass, fescue, and kale, to speciality vegetable seeds such as pak choi, spinach and radish.

“The vegetable crops can be quite profitable if you get a good yield. In fact, they can be our most profitable crop, but they are also our most risky,” he notes.

That is even with irrigation, which is now available on 90% of his land. Without it he could not get a contract, he notes.

Annual margin from herbage seeds such as ryegrass and fescue (see table), including a cut of silage and winter grazing, more or less matches his wheats, which average 13.5t/ha.

But Mr Watson stresses that output is only possible because he invested in irrigation. Last harvest, after the worst drought for decades, his wheat still did 12.5t/ha.

“It had six or seven passes with the irrigator applying 45mm a time. At NZ$1/mm/ha (37p/mm/ha) that pushes up the growing cost quite a bit.”

But not all growers are achieving such returns, particularly on dry land. At Methven, John Wright and his brother”s wheat crops average 9t/ha, but last summer yields slumped to 5.5t/ha due to the drought. “

Last year was a real stinker. Two-thirds of our crop grows on winter moisture and we rely on some summer rain to top that up. We would be averaging 10t/ha but for last year.”

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