Kiwifruit Nutrition diagnosis of nutritional disorders
1. Factors for converting MAF Quicktest results to other units13.
| Note | Ca | K | Mg | P | S | |
| Reporting unit | ||||||
| µg/ml in extract | Ca × 25 | K × 4 | Mg × 1 | P × 0.05 | S × 0.2 | |
| µg/ml in soil | (1) | Ca × 113.6 | K × 18.2 | Mg × 4.55 | P × 1.0 | - |
| µg/g in soil | (2) | Ca × 125 | K × 20 | Mg × 5 | P × 1.1 | S × 1 |
| kg/ha-75 mm | (3) | Ca × 85.2 | K × 13.6 | Mg × 3.4 | P × 0.75 | S × 0.68 |
| me/100 g | (4) | Ca × 0.955 | K × 0.070 | Mg × 0.048 | - | - |
| me/100 g | Ca × 0.625 | K × 0.051 | Mg × 0.042 | - | - | |
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(1) Soil: extractant ratio 4.4:20 (v/v) for Ca, K, Mg, 1:20 (v/v) for P. (2) Approximate conversion for Ca, K, Mg and P based on a constant bulk density of 0.91 g/ml for prepared soil; note that this can vary between soils. Soil extractant ratio for S is 1:5 (w/w). (3) Assuming field soil has the dame bulk density as prepared soil (except S). (4) Assuming a constant bulk density of 0.91 g/ml and using experimentally determined relationships with exchangeable cations (determined at pH 7). (5) Theoretical conversion from µg/g soil, assuming constant bulk sensity of 0.91 g/ml and 100 per cent extraction. | ||||||
2. Frequently used units and abbreviations
g grams
µg micrograms (10-6 g)
mg milligrams (10-3 g)
kg kilograms (1 kg = 1000 g)
ha hectares (10 000 m²)
ml millilitre (1 litre = 1000 ml)
µg/g = mg/kg = ppm (parts per million)
µg/ml = mg/l = ppm (parts per million)
w/v weight per volume
w/w weight per weight
v/v volume per volume
3. Commonly used conversion factors
1 lb/acre = 1.121 kg/ha
1 cwt/acre = 125 kg/ha
1 ton/acre = 2.5 tonnes/ha
100 kg = 1.968 cwt