Farming was hampered by economic depression in the 1920s and 1930s, and labour shortages in the 1940s caused by the Second World War.
Between 1930 and 1950, the growth in sheep numbers slowed, and wool production and prices swung dramatically.
Dairying, however, continued to develop. The number of dairy cows more than doubled between 1920 and 1950. Dairy farmers used increasing quantities of superphosphate fertiliser to boost pasture production, and shifted from using fodder crops to feeding stock solely on pasture. Exports of butter and cheese increased from 75,491 metric tonnes in 1920, to 233,619 tonnes in 1950, and their value increased by over 450%.
Meat, wool and dairy products consistently earned over 90% of New Zealand’s export income. By 1950 New Zealanders enjoyed a high standard of living and, based on the average income per head of population, New Zealand ranked in the top five countries in the world.
During this period there were many technological advances that benefited farmers. For example, improved roading reduced the isolation of many rural communities and made the transportation faster and cheaper. The introduction of electric power to rural areas benefited farms, and tractors and new machinery made many jobs less labour intensive.
Science and agriculture
In 1926 the government established the Department of Scientific and Industrial Research (DSIR), which began with a strong focus on improving production in agriculture.
The Plant Research Station was set up in 1928, partly under the umbrella of the DSIR. That same year, Bruce Levy began a trial to identify superior strains of ryegrass and white clover for New Zealand conditions, and breed improved varieties. He became the leading advocate for increasing grassland production by sowing the best grass and clover species, liberally using superphosphate, and increasing stocking rates.
The native grass grub (Costelytra zealandica) is a serious pest in New Zealand. It is found throughout the country and causes millions of dollars of damage to pasture. In its larval stage, which lasts from early summer until the following spring, it feeds on the roots of white clover and ryegrass, the country’s two most important pasture plants.
Improving pastures was one way of increasing production; others were livestock improvement and better grazing management. In the 1930s, at Massey College, Geoffrey Peren and Francis Dry began work on improving the performance of Romney sheep in North Island hill country through breeding. This work led to the Perendale and Drysdale breeds.
In 1943 C. P. McMeekan was appointed superintendent of the Ruakura Animal Research Station near Hamilton, where he led a team of scientists working on animal nutrition, genetics, artificial insemination and improving the milking process. This research had almost immediate benefits for dairy farmers.
A major breakthrough was the discovery in the 1930s that bush sickness, which afflicted livestock in the central plateau, could be cured by applying cobalt to the soil. Other discoveries of trace element deficiencies in the 1960s, especially those related to selenium, molybdenum and sulfur, led to improved animal health and productivity in the South Island.
Concern had been growing over the environmental consequences of pastoral farming and land development in North Island hill country and South Island high country. Awareness increased in the 1920s and 1930s, as soil erosion became more obvious.
In 1925 the government appointed a committee to examine the deteriorating Crown lands west of Lake Taupō. In the late 1930s scientists from the DSIR mapped the badly eroded areas of the North Island, and concluded that some of the most affected country needed to be taken out of production. Serious flooding in Hawke’s Bay in 1938 made the wider public more aware of the problem.
Lance McCaskill, from Lincoln College, and Kenneth Cumberland, from Canterbury University, lobbied for a soil conservation agency to protect soils from erosion. In 1941 the government responded by establishing the Soil Conservation and Rivers Control Council. Between 1943 and 1948 catchment boards were established throughout the country to manage river control and soil conservation at a local level.
Nevertheless, production declined in both the North Island hill country and South Island high country. In dry areas rabbits numbers exploded in the mid- to late 1940s. Wool prices were low and farmers lacked capital to invest in improvements.