Ground Cover Supplement : GC Supplement - Pastures
GROUND COVER PASTURES 9 ANNUAL LEGUMES BISERRULA HAS EMERGED out of the CRC for Legumes in Mediterranean Agriculture (CLIMA) and the National Annual Pasture Legume Improvement Program (NAPLIP) as an exciting prospect for wheatbelt pastures in southern and western Australia. Biserrula is native to the Mediterranean areas of Europe and north Africa and the Canary Islands. There are two varieties of biserrula now commercial- ised. Casbah (released in 1997) is a mid-season cultivar flowering in WA about 100 to 105 days after emergence. It is suited to regions with 325 to 500 millimetres of annual rainfall. MauroA (released in 2001) is a mid- to late-maturing biserrula cultivar, flowering in WA about 115 to 120 days after emergence. It is suited to regions with 450 to 700mm annual rainfall. Biserrula is a high-quality forage in terms of dry- matter digestibility, metabolisable energy and crude protein. It is a prolific seed producer, with seed yields ranging from 300 to 1500 kilograms per hectare. One of the main attributes of biserrula is the capacity to set seed under high grazing pressure, similar to subterranean clover. About 40 per cent of the seed can survive inges- tion by sheep, so summer grazing is unlikely to harm the stand density or long-term persistence, unlike annual medics, which are sensitive to overgrazing in summer. Biserrula has an acid-tolerant rhizobia which can persist and give excellent nodulation on soils with pH as low as 4.0 (CaCl2). The plant has a deep root system (up to two metres), which is very important for plant survival during long periods of drought and to provide a longer period of green feed for grazing animals (two to three weeks longer than subterranean clover). Biserrula is very hardseeded and its pattern of sof- tening suggests that it is ideal for ley farming systems. Biserrula appears to have some protection against false breaks of season (germinating rains followed by drought) as seeds soften in the late summer-autumn period. This gives biserrula a distinct advantage over subterranean clover, which is highly vulnerable to seedling losses in false breaks of season. With its combination of high seed yield and hard seeds it is likely that biserrula will survive in the seed bank for many years, allowing the use of multiple crop sequences of up to five years. The use of biserrula in WA is not only related to its persistence and productivity but also to an emerg- ing potential to control weeds with grazing during the pasture phase. Farmer observations and recent experimental work have shown differences in the acceptability of Casbah pastures to sheep during the Biserrula emerges as an exciting prospect for wheatbelt pastures PROJECT: NATIONAL ANNUAL PASTURE LEGUME IMPROVEMENT PROJECT -- WESTERN AUSTRALIA. ANGELO LOI growing season. Over a short period of time, sheep begin to avoid biserrula and preferentially graze the non-legume components of the pasture, rapidly leading to legume dominance. This is highly beneficial for the management of herbicide resistant weeds such as annual ryegrass, and is likely to reduce the use of herbicides in cropping systems. Isolated incidents of photosensitivity have been observed in sheep grazing biserrula-dominant pastures, so farmers are advised to monitor sheep closely in spring and avoid grazing lambs and bare-shorn animals at this time. Dr Angelo Loi is a pasture research officer with the Department of Agriculture and Food, Western Australia. GRDC Research Code UWA360 More information: Department of Agriculture and Food, WA, Farmnote No. 37/2005 Biserrula is a high-quality forage, can set seed under high grazing pressure and has an acid-tolerant rhizobia which can persist on soils with a pH as low as 4.0. Angelo Loi in a paddock of biserrula: an exciting prospect for wheatbelt pastures in southern and western Australia.
GC Supplement - Growers sharing knowledge
GC Supplement - Subsoil constraints