Grains and field crops
Trial 87A19, 87MT50
Persistence of AMV in annual medic swards.
In 1990, the fourth year of this trial, although the medic plants were numerous the burr medic swards at Avondale grew poorly and weeds were widespread in the plots, especially long storkbill, flatweed and grasses. Poor growth was due to nodulation failure caused by low soil pH (5.3 in water). Hardly any medic plants were left in the Zodiac medic plot at Avondale while a few remained at Mt. Barker.
Location: Avondale and Mt. Barker.
Effect of AMV on the productivity of burr medic swards after cropping, regeneration and grazing.
88A21 was allowed to regenerate in 1990 following cropping with barley in 1989. It was hard grazed in summer and autumn (first germination was in February following summer rains). Then, at the beginning of June sheep were excluded and the buffers resown with oats. It was subsequently grazed again from mid-August to early-September (3 weeks) but as grazing was uneven all plots were mown (4 cm cutting height) at the end of this period to even them up.
Effect of AMV on the productivity of newly sown burr medic swards.
90A5 was sown in early June and grazed portions of plots were grazed from August 15 - September 7. There were major differences in the plots due to seed source. With all three cultivars the infected seed stocks produced more vigorous growth. This was visible from July to September in ungrazed portions of plots but was largely removed by grazing. When the phosphorus content of the seed stocks sown was determined it was higher in infected than healthy seed. Seed phosphorus seemed the most likely cause of better growth of infected seed.
Number of Pages
Jones, R A, Nicholas, D A, Baker, A R, McKirdy, S, Skinner, P W, and Poole, C. (1990), Virus diseases of annual medics.. Department of Agriculture and Food, Western Australia, Perth. Report.