The influence of rate of stocking and application of superphosphate on the production and quality of wool, and on the gross margin from wethers

Abstract

From 1964-1969 wool production, liveweight, and wool quality traits were measured on Merino wethers stocked at rates ranging from 2 per acre (4.9 ha-1) to 8 per acre (19.8 ha-1) on plots receiving 50, 150 and 250 lb an acre (56, 168, and 280 kg ha-1) superphosphate annually. The effects of increases in the rate of stocking and the amount of superphosphate applied, on wool quality traits and gross margin returns during the entire period and on wool production from 1967 to 1969 are reported. In each year (1967 to 1969) wool production responded to an increase in superphosphate application from 50 to 150 lb but not to an increase from 150 to 250 lb. The response was substantial only in 1968. All wool traits were affected by the level of superphosphate in one or more years. In terms of gross margin returns ($/acre) it was profitable to apply more than 50 lb an acre of superphosphate in 1966 only. In 1969 it was clearly unprofitable to do so, and in 1965, 1967, and 1968 there was no economic advantage to any particular level of superphosphate application within the given cost structure.