Samples
were analysed for Kjeldahl nitrogen (N), total phosphorus (P), total
potassium (K), total magnesium (Mg) and total calcium (Ca).
Kjeldahl N was determined using Buchi digestions and steam
distillation. Foliar samples were analysed for K, Ca and Mg
concentration by nitric/perchloric acid digest followed by atomic
absorption spectrophotometry using a Varian FS220 atomic
absorption spectrophotometer. Phosphorus was determined via
the Ammonium Molybdate colourimetric determination, using a
Cary 1E spectrophotometer.