Evaluation of the agronomic potential of pasture legume introductions on droughty outwash soils

Abstract

Lucerne is no more productive than traditional clovers on drought-prone, low fertility soils with acid subsoils. Introductions of a variety of alternative legumes, and in particular Lotus corniculatus (birdsfoot trefoil), were compared on a high country yellow-brown earth soil developed on outwashed plains with acid subsoils. Lines and cultivars were scored for a variety of agronomic attributes, the most important in this environment being dry matter yields, autumn production, persistence, and drought tolerance. Principal component analysis was used to order the large amounts of data. Several cultivars and lines of L. corniculatus originating from Mediterranean/mild temperate, maritime Europe/cool temperate climates and South America were superior to other legume species and to other cultivars and lines of L. corniculatus. Individual plants which were consistently superior were selected to be cloned to produce an experimental "Dry land" cultivar.

Weed Suppression in Only-Legume Cover Crop Mixtures

“…Therefore, all treatments produced more or less equal biomass and suppressed weeds with the same efficiency. This finding was contrary to expectations for AC, as this species was supposed to be negatively affected by drought conditions [29,52,53] and consequently its strength to suppress weeds would be lower. The unexpectedly outstanding performance of AC in the dry season, in 2016, suggests that the effect of water level in limiting the growth of AC might be alleviated by other factors (e.g., soil physical, chemical, and biological properties).…”

“…Therefore, all treatments produced more or less equal biomass and suppressed weeds with the same efficiency. This finding was contrary to expectations for AC, as this species was supposed to be negatively affected by drought conditions [29,52,53] and consequently its strength to suppress weeds would be…”

“…BM is a fast-growing perennial legume [29,46] that is well adapted to warm and dry conditions [47,48], has a short-medium growth habit that forms a superior ground cover, and regrows fast after cutting [49][50][51]. AC is a slow-growing perennial legume that is drought-sensitive and well adapted to cool and wet conditions [52,53] and has an upright growth habit with a single crown from which multiple florets are produced [54]. Therefore, the two legume species are supposed to represent asynchrony in growth rates and asynchrony in response to environmental conditions; thus, strongly suppressing weeds.…”

Effects of mixing two legume species at seedling stage under different environmental conditions

“…The lower germination percentage of AC than of BM under dry conditions ( Figs. 2A , 3A – 3D , 5A and 5B ) is in agreement with some studies reporting AC’s sensitivity to dry conditions ( Chapman, Dodds & Keoghan, 1990 ). However, in a recent study by Elsalahy et al (2020) , it was found that the drought resilience of AC is higher than of BM.…”

“…Nonetheless, it was also reported for BM that the optimal range of temperatures lies between 10 °C and 20 °C ( Sharpe & Boyd, 2019 ). Conversely, AC is a more slowly growing and comparatively drought-sensitive perennial ( Chapman, Dodds & Keoghan, 1990 ), with less tolerance to drought or high temperature ( Sheaffer et al, 2003 ), and best adapted to cool and wet areas ( Döring et al, 2013 ; Nation, 1989 ). The minimal germination temperature of AC has been given as 2 °C ( Kahnt, 2008 ) or 5 °C ( Hartmann & Lunenberg, 2013 ).…”