THE POTENTIAL FOR OVERSOWING; LUCERNE ON STEEPLAND SOILS IN NORTH AND CENTRAL OTAGO

Abstract

A summary of results is given from trials investigating the effect of sowing date, lime, altitude, aspect and seed treatment on the establishment and production of oversown lucerne at various sites in the semi-arid to sub-humid zones of North and Central Otago. , Spring sowings were generally more successful in establishing lucerne than autumn sowings. Early to mid-August sowings appeared more satisfactory on low altitude sunny country, while colder, shady aspect country responded to slightly later sowings. Higher numbers of plants established at the higher altitudes. Lime pelleting and heavy inoculation rates increased lucerne establishment when favourable environmental conditions followed sowing, but did not ensure establishment under adverse conditions. At pH 6.2 to 6.6, there was no consistent response in lucerne establishment to 1200 kg/ha lime, although up to 60% increases in establishment were obtained on some sites. Herbage yields of over 5 t/ha dry matter were recorded on the best plots, at lucerne plant densities in excess of 10 to 20/ms. With present techniques, oversowing of lucerne in this environment is not recommended, except on damper sites, as satisfactory lucerne establishment has not been achieved consistently in trial work.