A case study of farm-based solutions to water logging and secondary salinity in southwestern Australia

Abstract

The ‘Ucarro’ farm is located in the upper catchment (33°S117°E) of the Carrolup River, a tributary of the Blackwood River in southwestern Australia. When the present owners of the farm took over the property in 1975, the stream running through the farm was becoming saline and access to the lower portions of the farm was frequently hindered by water logging in the wet winter months. The paper describes the decision made by the present owners to develop a whole farm plan to ameliorate water logging and prevent the development of secondary salinity. The plan included the grading of interceptor drains with a fall of 1:300 along the contour 150–200 m apart down the slope and the locating of dams along the drains to hold water for the dry summer months. Belts of three or four species of trees were planted on the down-slope side of the drains after leveling the spoil from the drain and deep-ripping the soil. The benefits of this plan included reduced water logging, salinity and wind erosion, and increased yields, stocking rates and lambing percentages. While the costs of the drains, trees and fencing were about US$ 2760 (US$ 1=AU$ 1.7, June 2000) per km, gross margins have increased by about US$ 2.70 ha −1 per year as a result of increases in cereal yields from 2.2 to 3.2 t ha −1, increased carrying capacity of the pastures from 8.5 to 11.0 dry sheep equivalents (DSE) ha −1, increased lambing percentages from 77 to 86% and increased income from aquaculture (fresh-water crustaceans) produced in the farm dams.