Constraints and opportunities for lucerne (Medicago sativa L.), Caucasian clover (Trifolium ambiguum M. Bieb), and Russell lupin (Lupinus polyphyllus L.) in the high country of New Zealand (PDF 48.1 MB)
Saman investigated a range of perennial legumes to identify which were best suited to the low fertility regions of the New Zealand high country. At Lees Valley, Canterbury Caucasian clover (Trifolium ambiguum) was the most persistent legume by Year 6. A pot experiment showed low pH and high aluminum (Al) soil suppressed the growth of fine roots and inhibited nodulation of lucerne (alfalfa; Medicago sativa), more than Caucasian clover. At Glenmore Station, the percentage of nodulated Russell lupin (Lupinus polyphyllus) plants was constantly over 75%. Nodulation of lucerne and Caucasian clover, nodulation decreased to zero and 25%, when >5 mg Al/kg soil. The main limitation for lucerne and Caucasian clover was nitrogen deficiency via depressed N fixation. Eight naturalized strains of Sinorhizobium meliloti were identified from lucerne nodules grown in different high country regions. This project was part of the High Country Forage Improvement programme funded by The New Zealand Merino Company Ltd. Saman was supervised by Prof. Derrick Moot, Dr Jim Moir and Associate Prof. Hayley Ridgway.