The effect of molybdenum and of lime dressings on the copper and molybdenum contents of some pasture species in the Murray Valley.

Abstract

Dressings of 2 oz. and 2 lb. of ammonium molybdate with and without 1 ton of ground limestone per acre were applied to 0.03-acre plots of the natural pasture at Barooga Field Station in a latin square design with six replications; the other two treatments were 1 ton limestone only and untreated. In the autumn of the following gear one-half of each plot was retreated at the same rate of dressing as in the previous winter. Samples were collected at intervals of those species which formed an appreciable proportion of the pasture, and their copper and molybdenum contents determined. It was found that dressings with up to 2 lb. of ammonium molybdate or 1 ton of limestone per acre, or both, had no effect on the copper content of the pastures. The uptake of molybdenum varied considerably amongst the species; the legumes took up the greatest amount. The molybdenum content of Heliotropium europaeum was practically unaffected by the dressings used.