Are you ready to withstand a big dry?

Here in New Zealand, NIWA Scientists say the likelihood of hot conditions rises when global mean temperatures are higher; but NZ’s climate is also influenced by prevailing wind patterns.

Growing conditions on farms are very different depending on whether we have a La Niña or El Niño weather pattern. La Nina brings wet weather with more storms to eastern NZ, while El Nino brings hot dry weather particularly to east coast regions, and very often droughts.

If higher global temperatures also impact NZ we could be looking at hotter El Niño conditions than normal, which will affect our farmers and our food production. If you’re a home gardener the changes will also affect you.

Warmer weather can mean a longer growing season, so it can be good for growing fruit and vegetables -- if they get enough water at the right time. When temperatures are warmer the rate of evapotranspiration is higher, so water demands increase. And if there is less rain than usual due to the weather pattern, this also creates the need for water.

Too much heat is harmful to crops which stop growing at about 32 degrees C, but they can recover with water or cooler temperatures.

During hot weather, irrigation systems can struggle to keep up with watering requirements. Farmers who know a hot season is ahead need to budget their water use. Vegetables, fruit and grains require regular watering as part of their growth cycle, while grass is more drought resistant and can cope with longer gaps between watering.

While most of NZ’s vegetables, fruit, grapes and cereal crops are grown with irrigation, most sheep and beef farms don’t have irrigation and about 75% of dairy farms are not irrigated.

My family farmed through many years of drought in Australia, with much of our farm not having access to irrigation. During summer, temperatures were often in the 40s. When the temperature soars, water becomes the most critical issue on the farm. That includes keeping stock supplied with drinking water: they can survive for quite a while on minimal feed but can’t go without water.

When dry conditions are on the horizon, you have to be forward thinking. We looked at how to plan to have enough supplementary feed, as well as whether we could reduce stock before the peak drought period when we had the least feed on hand.

We were lucky to have part of the farm irrigated, and we had to be careful how we used our limited water allocation.

The drought in Australia continues to impact on farmers very severely. Warmer weather will throw up challenges for our farmers, however, NZ has the benefit of being relatively water-rich compared to Australia. In our east coast regions, irrigation is widely used and plays an important role in helping us weather hot spells.

Large-scale water storage, like the Waimea Dam and the Hurunui Water project, benefit farmers and urban communities. 

A look at Australia shows that a lack of water has wider impacts on the whole economy. We need to maintain NZ’s competitive advantage as an agricultural economy and ensure we can continue to produce food through all types of weather.

— Steve Breneger, formerly an NSW farmer, educates farmers and growers in irrigation efficiency.