Legumes improved dryland grazing systems in New Zealand

Abstract

In this paper we summarize the use of lucerne (Medicago sativa L.) and subterranean clover (Trifolium subterraneum L.) in dryland grazing systems in New Zealand over two decades. These systems are located in the rain shadow of the Southern Alps. Low annual rainfall (350–800 mm) and high potential evapotranspiration (1400–1600 mm) are coupled with strong Northwest winds that produce daily evapotranspiration rates up to 8 mm. Together the climate and high soil variability (60–300 mm of water holding capacity) leave a 3–4 month window of reliable pasture growth. Each year the spring-born lambs are sold for export or finishing by specialist producers to enable the farm to destock and avoid the dry summer period. We aimed to develop sustainable grazing systems in this environment. This required plants to maximize spring water use efficiency, and provide a bulk of nutritious animal feed for grazing in situ during and shortly after lactation. This paper summarizes 15 years of on-station research and on-farm demonstration that has transformed some of these dryland farms. The research was based on first principles associated with the need to convert limited water to high quality feed to meet animal demand.