Plant nutrition development

South Australia’s stone fruit industry has benefited from a range of plant nutrition research projects over the decades. Some the most significant projects include:

• Evaluation of sulphate of ammonia as a source of nitrogen for orchards – Blackwood Experimental Orchard 1932.
• Assessment of permanent sod cultures to overcome soil degradation problems associated with frequent cultivation of orchards – Blackwood Experimental Orchard 1950s.
• Studies on the role of calcium metabolism in internal breakdown of apricots in 1961–2.
• Use of zinc foliar sprays to overcome zinc deficiencies, along with assessment of zinc oxide vs zinc sulphate sprays in the early 1970s.
• Establishment of soil and tissue analysis laboratories at Loxton and Northfield. The Mill Laboratory annex of Loxton Research Centre was established in the mid 1960s and moved to the main Loxton Research Centre with construction of a new office and laboratory complex in 1981. The tissue analysis services from these centres provided orchardists with vital nutrient data over almost 40 years.
• Leaf analysis surveys (Dr Ben Robinson in cooperation with district horticultural advisers) were undertaken during the 1970s and 1980s to validate plant test standards used in North America and Europe for South Australian conditions.
• A major study of the nutritional status (using leaf tissue analysis) of the canning peach industry was commenced by P.R. Nicholas and J.B. Robinson in 1972. This surveyed 30 clingstone peach orchards over 3 years.
• Publishing of national standards for interpretation leaf analysis of horticulture crops (“Plant Analysis: A Manual” by Doug Reuter and Ben Robinson, 1986).

Improved knowledge of soil and water interactions along with better irrigation management has greatly reduced the range of nutrition difficulties experienced by orchardists.