Phosphorus acquisition of wheat, pea and narrow-leafed lupin under different P supplies

Abstract

The aim of this study was to compare wheat, pea and narrow-leafed lupin in terms of their ability to acquire P from soil. Two experiments were conducted at the Universidad Austral de Chile. Treatments combined (i) three species (wheat, pea and lupin) and (ii) two rates of P fertilization (0 (P0) and 50 mg P kg-1 (P1)). In Experiment 1 and 2, shoot biomass was affected (P < 0.01) by genotype, P rate and the genotype x P rate interaction. In wheat, pea and lupin P0 reduced this trait by 92, 76 and 41%, respectively, whereas in Experiment 2 these reductions were 86, 58 and 44%, respectively. P1 increased the P uptake of wheat, pea and lupin by 17, 5 and 3 times, respectively. Wheat, pea and lupin showed the highest, intermediate and lowest cumulative root length under P fertilization. The root: shoot ratio and P uptake per unit root length was affected by genotype, P rate and the genotype x P rate interaction. Wheat, pea and lupin showed the highest, intermediate and the lowest root: shoot ratio, respectively. In contrast, wheat and lupin showed the lowest and the highest P uptake per unit root length in both experiments. The present study showed consistent differences between wheat, pea and lupin regarding their sensitivity to P deficiency and the strategies that these species have developed to acquire P from soil. This information could help improve fertilizer management strategies and optimize soil P use.