EVALUATION OF N-RECOVERY FROM MUCUNA PLACED ON THE SURFACE OR INCORPORATED IN A BRAZILIAN OXISOL

Nutrient culture studies frequently involve the use of balancing ions to equalize concentrations of essential nutrient elements. In a pot experiment in controlled environment with Lupinus angustifolius, growth and nodulation were assessed following calcium treatment (15 m M) using the acetate, chloride and sulphate salts in various combinations. Chloride depressed nodulation at levels higher than 20 m M; nodule mass and number were highest at the maximum sulphate concentration (13 m M). At the lowest sulphate level (2 m M), nodulation and root growth were depressed by 4 m M or higher acetate. Nodulation (dry weight and numbers of nodules) was maximized at 13 m M sulphate/4 m M chloride. © 1990 Kluwer Academic Publishers.