Introduction
Trace elements, as the name suggests, are only required in very small amounts but deficiency can lead to considerable yield loss. Trace elements are required by the plant for many important functions such as photosynthesis, general metabolism, growth and nitrogen use.
Western Australian coastal sands are naturally deficient in almost all trace elements. To achieve maximum yield, potatoes require adequate applications of boron (B), copper (Cu), manganese (Mn), molybdenum (Mo), zinc (Zn) and sometimes iron (Fe).
Soil conditions and soil tests
Soil tests and associated recommendations for trace element fertiliser applications are available from commercial laboratory services within and outside Western Australia. If using Australian services, ensure the laboratory is NATA (National Association of Testing Authorities) accredited as this guarantees the tests meet minimum quality standards. Accurate soil tests allow accurate fertiliser recommendations which are important in correcting trace element deficiency, avoiding toxicity and maximising profit.
On alkaline soils, iron, manganese, copper and zinc may be poorly available while molybdenum may be poorly available on acid soils.
In both situations, factors such as waterlogging, nutrient interactions and environmental conditions may induce nutrient deficiency, even though the trace elements have been applied before planting. Deficiency may be alleviated by post-planting foliar applications.