Competition and persistence of strains of Rhizobium trifolii in relation to inoculation level and lime pelleting on white clover sown into cultivated soil

摘要

Abstract Five strains of Rhizobium trifolii were assessed for their ability to compete with naturalised strains in nodulating white clover (Trifolium repens) sown in cultivated soil. At the initial assessment 5 months after sowing, the inoculant strains at the normal rate of sluiry-inoculation had formed only a small percentage of the nodules present. Increasing the inoculation level to 10 times normal or lime pelleting increased the percentage of nodules formed by all strains apart from PDDCC 2163, which formed a low percentage of nodules irrespective of inoculation and pelleting treatments. The percentage of nodules formed by Strains 2153, 2666, and 2668 declined between the 5- and 18-month assessments so that the percentage of nodules formed by Strain 4144 after 18 months was about twice that of the other strains. Inoculating with Strain 4144 significantly increased %N and total N uptake in clover in spring, 10 months after sowing, compared with the other inoculant strains. However, there were no signi...