Persistence and growth of Maku lotus on contrasting aspects at high altitude

Abstract

Maku lotus plants were grown in snow tussock grasslands at 1460 m altitude on steep ungrazed slopes. A total of 960 plants were transplanted in spring 1980 to five sites. In March 1984 survival was 72% and 68% on two NW sites and 66%, 56% and 46% on three ESE sites. Survival rates did not differ between 100 and 300 kg/ha sulphur enriched superphosphate applied in the transplant year, but dense native vegetation appeared to contribute to poorer survival on the eastern slopes. Mean lotus plant size, expressed as an index of ground spread was consistently larger on NW than on ESE, and in February 1984 was three times larger (1422 cm² cf. 429 cm²). Mean DM yields per plant in February and March 1984 were from 1.3 to 3.0 times greater on NW sites. Ground spread indices and D.M. yields showed a response to the higher rate of fertiliser on some sites only. Higher air and soil temperatures on NW aspect, particularly in early spring and in autumn favoured a longer period of growth compared with E.S.E. The trials showed that Maku lotus could be a valuable herbage resource on warmer northerly aspects above 1000 m. In addition, the high variability amongst lotus plants suggested that production for such cool environments could be improved by selection within existing populations.