The control of take-all wheat after a long period of pasture

Abstract

A field experiment was conducted to ascertain the effects of various periods of bare fallow and the growth of certain crops on the occurrence of take-all in a subsequent wheat crop. At the commencement of the investigation the experimental site had not been cultivated for many years and it carried a variety of grasses whose susceptibility to take-all is known and whose infection by Ophiobolus was established. Bare fallow periods commencing in July or earlier in the year preceding seeding, and the growth of oats for grazing during a similar period, were each about equally effective in minimizing take-all. Shorter bare fallow periods and the growing of oats or peas to the stage of grain production were all relatively less effective. Barley as the preceding crop probably aggravated the incidence of the disease beyond what might have been expected on newly ploughed grassland. Apparently none of the treatments, which included bare fallow periods of more than twelve months, was effective to the point of eliminating sources of infection.