Can summer-active perennial species improve pasture nutritive value and sward stability?

Abstract

Although generally well adapted and productive, the summer-dormant perennial pastures of southern Australia do not provide a year-round, high nutritive value feed base, they fail to respond to summer rainfall, and they are inefficient in using stored soil water, which can contribute to dryland salinity. An experiment was conducted to test the hypothesis that deep-rooted, summer-active perennial pasture species, matched to soil type, can be grown successfully in southern Australia to increase pasture and animal productivity and to provide high quality feed in summer–autumn. Specifically, the experiment compared a traditional perennial ryegrass (Lolium perenne L.) pasture system with two systems based on summer-active species: the triple system with lucerne (Medicago sativa L.) and tall fescue (Lolium arundinaceum (Schreb) Darbysh), and the novel system with chicory (Cichorium intybus L.) and kikuyu (Pennisetum clandestinum Hochst. ex Chiov). The experiment incorporated three livestock systems (two sheep and one cattle) and took into account the three main soil types occurring on the DPI Hamilton research farm. After 4 years the perennial ryegrass, lucerne, and tall fescue components were all persisting well and providing feed with high nutritive value (all with frequency scores >70% in the last year of the experiment). The chicory and kikuyu pastures declined over the life of the experiment and were contributing little at the end (frequency scores <15% in the final year). Lucerne, tall fescue, and perennial ryegrass cv. Banquet were able to respond to summer rainfall events to provide valuable, high-quality feed at a time when the quality of perennial ryegrass pasture is normally at its lowest; April 2007 crude protein per cent dry matter values were Avalon perennial ryegrass 16.6, Fitzroy perennial ryegrass 15.6, kikuyu 24.2, lucerne 25.8, and tall fescue 20.3 following a 98 mm rainfall event in late January 2007. This study has shown that the triple and ryegrass systems were persistent and of high nutritive value, with the sown perennial species contributing the majority of the sward dry matter during the growing season.