Uptake of electricity
From the early 20th century some larger isolated farm stations generated power from their own small hydroelectric plants. The first electricity on many smaller farms also came from hydroelectric generators.
Between the world wars, the extension of power lines to farms progressed. Tasks such as pumping water for stock, irrigation, drainage and spraying, became increasingly dependent on electricity. From only 456 electric motors in use on farms in 1921, the number soared to 61,826 in 1941, and 145,071 in 1958.
Electric tractor
To increase demand for electricity, in the 1930s Mr H. Kemp, engineer for the Ashburton Electric Power Board, designed a tractor with an electric motor. Power came from high-tension mains via a transformer mounted on a truck, linked to the tractor by a feeder cable. Eight such tractors were made, but they could not compete with models powered by cheap oil fuels.
Dairying
Electric refrigeration for milk tanks was advertised as early as 1928. Gradually, electric milking and separating machines replaced those run by internal combustion engines. Electric light made early morning milking more comfortable, and electric water heating meant farmers no longer needed to light fires to boil water for cleaning and sterilising.
The electric rotary platform was developed by Merv Hicks of Eltham in 1969, to make milking more efficient. Cows stand on a slowly rotating platform, and only a small number of operators are needed to milk them. Once milked, the cows back off the platform and make their own way back to pasture.
Fruit growing
Stationary spray systems with electric pumps were in use in orchards by the 1930s. Electric refrigeration was advertised for fruit stores after the Second World War, and an electric conveyor belt was developed for fruit sorting by 1949. By the mid-1980s electric turbines were used in vineyards to drive warm air downwards on frosty nights.
Stock management
The electric fence appeared around 1937 and became widely used, mainly in dairying. It is particularly helpful for break feeding – confining stock to one part of a pasture, and allowing the animals an additional area each day, to ensure no pasture is wasted. As mains supply increasingly reached into sheep-farming areas, electricity was used to power shearing machines.
Irrigation
Spray irrigation was being used on pasture from about 1947. From the mid-1980s large electrically powered spray irrigators were being used on pasture in flat, dry areas of the South Island.
Electronic technology
In the late 20th century a new wave of mechanisation began with the introduction of electronic technology. An early application was using lasers for determining levels when installing drains and earthworks in border dyke irrigation. From the late 1980s electronic machines were used for weighing stock and detecting pregnancy. Computerised spray irrigation allowed precise amounts of water to be delivered to different areas under a variety of conditions. Global positioning technology has made the delivery of fertiliser and pesticides, and the preparation of farm maps, more accurate.
Electronic record-keeping and computer databases became significant in planning and stock breeding. Computers transformed rural communications, though speed on the internet often suffered from the limitations of rural telephone lines.
