Leaf testing is an important tool to have in your nutrient management toolbox.
Leaf testing compliments soil testing, evaluating the effectiveness of the fertiliser program.
Leaf testing is an important tool to have in your nutrient management toolbox.
Leaf testing compliments soil testing, evaluating the effectiveness of the fertiliser program.
Leaf testing enables nutrient trends on-farm to be identified and monitored over time. The data can also be used collectively to determine trends across a district, region or industry.
Leaf testing can be used as a diagnostic tool to:
Caution is needed when interpreting the results of leaf test as other factors such as; age of the plant, variety, moisture stress and pest and disease damage can influence nutrient levels in a plant.
SRA CRITICAL LEVELS FOR THIRD LEAF ASSAYS – Australian Sugarcane Nutrition Manual, 2018 |
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Third leaf assay |
Unit |
Critical level of assay |
Nitrogen (N) | % | November to mid-January: 1.9
Mid-January to February: 1.8 March to May: 1.7 |
Phosphorus (P) | % | 0.19 |
Potassium (K) | % | 1.1 |
Calcium (Ca) | % | 0.2 |
Magnesium (Mg) | % | 0.08 |
Sulfur (S) | % | 0.13 |
Copper (Cu) | mg/kg | 2 |
Zinc (Zn) | mg/kg | 15 |
Manganese (Mn) | mg/kg | 15 |
Boron (B) | mg/kg | 1 |
Molybdenum (Mo) | mg/kg | 0.08 |
Silicon (Si) |
% |
0.7 |