Effect of forage legumes on phosphorus availability to the following wheat crop in a Black Chernozem

Abstract

Including forage legumes in rotation with annual crops could increase phosphorus (P) availability to the annual crop due to their deep roots and intensive mycorrhizal infection. However, the benefit of forage legumes to increase soil P availability to the subsequent crop has gained less attention in the western Canada. The aim of this study was to investigate the impact of short rotation forage legumes on P availability to the following crop. Forage legumes evaluated in this study were red clover and alfalfa in comparison to an annual legume (pea) and non-legume (flax). The study was conducted at four sites across Saskatchewan. This poster reports on the results at one site near Melfort, SK. In this experiment, two-year alfalfa rotation produced the highest (P = 0.015) biomass yield. Inclusion of short rotation forage legumes had positive impact on wheat grain yield (P < 0.001) , but it did not affect wheat straw P uptake (P = 0.76). The amounts of soil P fractions extracted from all treatments were generally similar. The results suggested that a two year rotation of legumes may be too short a time period to significantly enhance in soil P availability to the following crop.