Pasture legume establishment from oversowing in drought-prone hill country

Abstract

Plant and environmental factors that affect pasture legume establishment from oversowing were examined in a series of experiments at Poukawa Research Station near Hastings. A combination of 2 sowing seasons and 2 soil conditions gave cool/ dry, cool/wet, warm/dry and warm/wet. The rainfall in the trial year (1992) was 933 mm compared with the mean of 771 mm. Eleven species (5 annual and 6 perennial legumes) from Lotus, Medicago and Tr$olium genera were used. Establishment was poor, less than 10% of total herbage yield (6 and 8 months after oversowing for the cool and warm seasons, respectively) being contributed by any of the legume species. The major cause of poor establishment was poor germination. Eighty percent of sown seed failed to produce a seedling. Although germination was worse under cool (8°C) conditions, particularly for subterranean clover, the major cause of poor germination was not identified. The usefulness of new legume species in dryland hill pastures will depend on the species being suited to establishment from oversowing and a better definition of the factors that affect successful oversowing. Keywords: drought, herbage yield, hill country, Lotus, Medicago, moisture, oversowing, pasture establishment, plant density, temperature, Trifolium