Effects of calcium carbonate and ammonium sulphate on manganese toxicity in an acid soil

摘要: The effects of increasing rates lime and ammonium sulphate on French beans were studied an acid red basaltic soil (pH 4.5-4.8), rich in manganese, the north coast New South Wales. Addition resulted increased plant yield, a higher pH, marked reduction available manganese manganese. Applications 2 or more tons per acre corrected toxicity. Ammonium applications acidified soil, levels both tissue, frequency toxicity symptoms at less than acre. At pH 4.7-4.8, exchangeable water-soluble sensitive to slight changes reaction. Changes between 5.2 6.0 caused only alterations plants. Two reduced level about half that untreated whereas 3 was necessary halve Close linear relationships found application Hyperbolic plants also fractions. Toxic leaves varied seasonally yearly, usually appeared when content first mature greater 600 p.p.m. winter crop. Symptoms closely related high results this trial indicate analyses are useful for predicting soils.