Southdown sheep no longer economical and smaller flocks averaged only 135 ewes apiece. The use of artificial fertilizers had gained ground, and the combine-drill, which sowed grain seeds and fertilizer together, rendered close-folding by sheep unnecessary. Gradually surrendering to basic arable farming changes, the Southdown became largely a grassland breed. During the interwar years, the United Kingdom was known for farm animal breeding, and pedigreed Southdowns were still being exported to most parts of the world, especially New Zealand. In 1937, the number of exported Southdowns reached 459 head. During the Great Depression, a severe and prolonged fall in the prices of
Southdown Power Station the plant and purchased the remainder in 2002. A third LM6000 gas turbine was added in 2007. This was operated in open cycle mode. Southdown was owned and operated by electricity generator Mighty River Power (now Mercury Energy), and complemented the company's renewable hydroelectric and geothermal stations. The station, strategically located in the south-central Auckland urban area, provided voltage support for the city, and helped to meet the peak demand requirements in the Auckland region. Southdown was also extensively used during dry periods, when there was insufficient water to run Mighty River Power's eight hydroelectric power stations on the Waikato