Variability in the growth and mineral nutrition of African clovers

Abstract

The effects of different P levels on the growth and N and P nutrition of 20 accessions from eleven Ethiopian clover (Trifolium) species were investigated in a glasshouse. The treatments were 0, 12.5, 25, 37.5, and 50 mg P/kg. Shoot and root dry matter yields plus N and P concentrations in the shoots were subjected to a numerical classification in order to simplify description and interpretation of the results. The classification separated the accessions into four main groups. These groups ranged from one which had accesions with low yield and low response to P to one which had accessions with high yield and high reponse to P. The most responsive group had also high uptake and utilization of N and P, but relatively low N and P concentrations in plant tops and low shoot/root ratios. Accessions in the two highest yielding groups responded to each increment in the P rate while accessions in the least responsive group did not respond to fertilizer above 12.5 mg P/kg. The fourth group had intermediate response between these extremes.