The chemical composition of rainwater at Taita, New Zealand, 1956-1958

Abstract

Rainwater has been collected monthly for three years at the Taita Experimental Station, 5 miles from the coast near Wellington, and analysed for the main elements present. The salt found, excluding bicarbonate, averaged 190 lb/ac/yr (212 kg/ha/yr) of which nearly 80% was sodium and chloride. Sulphate, 22 lb/ac/yr, and magnesium, 10 lb/ac/yr, were next in amount, followed by potassium and calcium with 6 lb/ac/yr each. Phosphate was very low (less than 1 lb/ac/yr). Total nitrogen was measured for a period and found to be double the inorganic plus albuminoid nitrogen. Accessions to the soil of nitrogen are probably not less than 3 lb/ac/yr. The ionic ratios showed that in periods with southerly storms the salt tended to approach the composition of sea water, and at other times calcium and potassium, and to a lesser degree magnesium and sulphate, reached higher proportions.