Lucerne establishment studies on two types of uncultivated country : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Agricultural Science with Honours in the University of Canterbury, Lincoln College

Abstract

In the South Island of New Zealand there are more than ten million acres of tussock and danthonia grassland. Many research workers and farmers have shown that much of this area can be greatly improved by the introduction of clovers. However in the semi-arid (<20” rainfall) and parts of the sub-humid (20-40” rainfall) area of these grasslands, lucerne (medicago sativa L.) may have a considerable agronomic advantage over clovers. This agronomic advantage is the result of lucerne’s higher annual dry matter production, its lower variability between seasons and its capacity to maintain production considerable longer into the dry summer period than any of the clovers (Iversen, 1965). The introduction of clovers by the low-cost techniques of overdrilling into, or broadcasting on the uncultivated turf, has proved relatively straightforward in most of these unimproved areas, and as a consequence the practice is now widespread. However, as yet, the introduction of lucerne into these areas by other than the costly conventional means of drilling in to a well cultivated, limed seed-bed is not common due to low seedling vigour and soil acidity problems which require further investigation. It is well recognised that over the majority of the area where lucerne would be of value on the unimproved grasslands, unless satisfactory alternatives to the conventional introduction methods are found, topographic and economic factors will prohibit its use. While considerable attention has been given to reducing the liming costs when establishing lucerne in these areas, little work has been conducted on alternative seed-bed preparation techniques to thorough cultivation. This thesis work was initiated to investigate sowing methods and seed-bed preparation techniques which could overcome the economic and topographic barriers to the widespread use of lucerne on these unimproved areas.