In praise of aerial topdressing

(First published in the Nelson Mail and Manawatu Standard, April 15.)

Driving through the Wairarapa back country recently, I saw a truck loading superphosphate into a topdressing plane in a paddock beside the road. I just had to stop and watch.

I’m no aviation enthusiast, but something about aerial topdressing fascinates me. It’s partly the skill of the pilots, partly the fact that it’s such a distinctive element of our rural heritage.

New Zealand pioneered aerial topdressing, using former World War II pilots to drop fertiliser in otherwise inaccessible places. It was a job that called on all their aviation skills. They flew low over hair-raising terrain and the death toll was high, but their work transformed vast areas of previously unproductive land into pasture.

Topdressing is part of the same number-eight wire tradition that gave us the electric fence and the Hamilton jetboat. All were New Zealand innovations that caught on around the world.

Waikato farmer Bill Gallagher made his first electric fence in the 1930s. The Hamilton-based company he founded is now an international leader in the design and manufacture of high-tech animal control systems.

Sir William Hamilton – another farmer, this time from South Canterbury – ingeniously adapted the principle of jet propulsion to boats, realising it would be the ideal way to navigate the shallow, fast-flowing rivers of the Mackenzie Country. His ideas have been adopted worldwide in craft ranging from jet skis to coastguard and naval vessels.

Such men represented something of a golden era in New Zealand – a time when resourceful and imaginative individuals, often with little formal education, made significant contributions to the country’s economic development.

How much less efficient farming would have been without the invention of a fence that could be picked up and shifted around, providing farmers with previously unimagined flexibility; and how different the vibrant tourist industry would seem without jet boats operating on our spectacular rivers and lakes.

Topdressing’s economic impact has been huge too. I see from a comprehensive entry in Wikipedia, the online encyclopaedia, that a John Chaytor of Wairoa is credited with the first use of aerial means to enhance agricultural productivity. In 1906, he spread seed from a tethered hot air balloon.

By the 1920s, the Americans were using planes for crop dusting. (Any Alfred Hitchcock fan knows about American crop dusting from the famous scene in North By Northwest, in which Cary Grant is attacked by a crop dusting plane and hides in a cornfield.)

But it was New Zealand that pioneered the application of fertiliser from the air. To use a phrase from crime novels, it had both the motive (large areas of the central North Island were deficient in trace minerals but too hilly to fertilise using trucks or tractors) and the opportunity (a lot of ex-RNZAF pilots were keen to apply their flying skills in civilian life, and there were war surplus planes available for conversion).

Private farmers acting on their own initiative were among the pioneers of agricultural aviation but the government, recognising the potential economic benefits, got behind it too.

I was intrigued to read that in 1949 one Stan Quill, a WWII flying veteran whose son was a friend of mine at school nearly 20 years later, was appointed head of an RNZAF research and development wing with the task of carrying out topdressing trials. Those trials culminated in a demonstration drop before an audience of farmers and reporters near Masterton, where I’m writing this.

The 1950s wool boom, triggered by the demand for warm uniforms for troops serving in the bitter cold of the Korean War, came along just at the right time, providing farmers with surplus capital that they spent on fertiliser and other improvements. By 1958, according to Wikipedia, there were 73 aerial topdressing firms flying 279 aircraft.

I grew up in a country town during that period and the noise of topdressing planes was part of the soundtrack of my childhood. There was a farm airstrip just a few hundred yards along the road from our house where planes would land on a slight uphill gradient and take off using the downhill slope to gain momentum.

All manner of aircraft were adapted for topdressing – puny Tiger Moths, lumbering twin-engined Bristol Freighters, Lockheed Lodestars and DC3s, De Havilland Beavers, noisy Ceres (a civilian adaptation of the air force Harvard) and, of course, the ubiquitous New Zealand-built Fletchers.

The Fletcher was purpose-built for flying in difficult hill country, often operating off tiny airstrips fiendishly sited on wind-swept ridges and nasty-looking spurs – anywhere there was a few metres of land that was more or less flat.

Originally designed in the US as a short-takeoff military attack aircraft called the Defender, the Fletcher was modified for topdressing purposes and in time became, to all intents and purposes, a New Zealand aircraft. From 1961, it was made in Hamilton.

The Cresco, direct descendant of the Fletcher, is a Kiwi success story that deserves greater recognition. It’s bigger than the old Fletcher and has a much more powerful turbo-prop engine, but with the same unmistakeable buzz-saw engine note.

When I see these planes weaving low through hills and gullies, I can’t help stopping to watch. Once, driving through a narrow gully on a winding gravel road in a remote part of the King Country, I damn near wet myself when a Cresco suddenly appeared under full power only metres above my head.

Aerial topdressing peaked in the mid-1960s. With the wisdom of hindsight, we can now see that it had some adverse effects. One was fertiliser runoff, but perhaps a more damaging consequence was that some steep back country was turned into pasture when it would have been better used for forestry, thus avoiding erosion.

Still, we can’t – and shouldn’t – overlook the contribution aerial topdressing made to our most important industry.

Now that I’m living in a country town again, I often see and hear topdressing planes flying out at first light and heading back to base at dusk. They are the bookends of the rural day.

It’s a good sight – a sign that farmers are spending money. When topdressing planes are mothballed because farmers can’t afford to buy fertiliser, as happened in the 1980s, we should all start to worry. We forget too easily that much of this country’s wealth still comes from the land.