Efficiency with which yellow serradella and subterranean clover use superphosphate on a deep sandy soil near Esperance, Western Australia

Abstract

In 1984, the efficiency with which an early- and a late-flowering yellow serradella (cv. Pitman and strain DP4 respectively) and a subterranean clover (cv. Seaton Park) utilise phosphorus (P) from superphosphate was compared on a deep sandy soil near Esperance, W.A. Phosphorus applications ranged from 0 to 90 kg/ha P. For each legume there was an approximately linear relationship between the amount of P applied and either the yield of dry herbage and seed, or the P content of dry herbage. The efficiency with which each legume utilised applied P (kg/ha) was determined by calculating the slope of the relationships between dry matter production, or phosphorus content of this dry matter, and the amount of phosphorus applied; this varied according to the growth stage at which the legumes were sampled. Strain DP4 utilised P more efficiently to produce dry herbage, and Seaton Park to produce seed. Pitman was the least efficient at utilising P for dry herbage production in September, and Seaton Park in early October. For dry herbage production in September and early October, the relationship between yield and P content was similar for all 3 legumes, and yield depended on the amount of P present in the herbage. For each legume, the rate of phosphorus applied had no effect on seedling emergence, the period between sowing and commencement of flowering, senescence or the weight per seed.