The effect of zinc deficiency as a factor limiting sugarcane growth (SRC Project BS14S - Final Report)
Results from this project confirm that substantial yield responses to zinc application can be expected in deficient soils in North Queensland. Deficiency is commonly associated with lime application. Three soil and two foliar analytical techniques have been evaluated for detecting zinc deficiency. Currently used critical levels for zinc in cane third leaves have been confirmed as the most reliable index of deficiency. The carbonic anhydrase assay on fresh leaf extracts shows promise for measuring active zinc and providing a rapid and reliable foliar index of zinc deficiency. Critical levels for soil zinc have been established for the standard DTPA extract and for two hydrochloric acid extracts. Both acid extracts are more reliable than the DTPA extract.