Auckland province at the top of New Zealand has peaty, organic soils, the result of high humidity and the rainforest that existed there before settlers cleared it for farming. The region is best for dairy and fat lamb production.
Active volcanoes dominate the plateau in the center of the North Island. Ash showers created the pumice soils which gave settlers and farmers many problems when trying to grow grass. Sheep and cattle became sick with cobalt deficiency until farmers top-dressed their land with cobaltized superphosphate.
The soils on the east coast of the North Island are seasonally dry and lime-rich. The Encyclopedia of New Zealand says they are fertile with deep, dark granular topsoils. The soils are best for intensive arable and sheep farming as well as apple and wine crops.
Mt. Taranaki-Egmont dominates the landscape on the west coast of the North Island and provides the rich volcanic soil. The yellow-brown loams come from the ash eruptions over thousands of years. They respond well to superphosphate topdressing and support mostly dairy and fat lamb production.
Wellington province has mostly yellow-brown earths formed under forests, which have nutty subsoils, according to the Encyclopedia of New Zealand. The soils need lime and superphosphate to make them productive. The land is mostly rolling, best for dairy and fat lamb production.
The South Island's Canterbury Plains have shallow, dry and stony soils. With irrigation from the rivers, the soils grow wool, cereal and pasture crops.
Westland, or the west coast of the South Island, has the highest rainfall of any region in New Zealand, at 100 inches per year, according to the Encyclopedia of New Zealand. The soil, formed under dense native forest, is wet and peaty. Only after extensive drainage has it become farmable.
The driest part of the South Island, under the wind-shadow of the Southern Alps, is Central Otago and the McKenzie Basin to the north. The stony soil is brown-gray and weakly acid to alkaline, according to the Encyclopedia of New Zealand. It supports fine (merino) wool growth and with irrigation, stone fruit.
