Response to fertilizer by short-term barrel medic (Medicago tribuloides) - barley grass (Hordeum Leporinum) pastures in the Victorian Mallee

Abstract

The response of barrel medic (Medicago tribuloides Desr.)-barley grass (Hordeum leporinum Link.) pasture to superphosphate applied as a topdressing, or with the preceding wheat crop, was measured at the Mallee Research Station, Walpeup. The pastures responded to topdressing in either the first or the second year in seven out of nine years. There were no consistent differences in the magnitude of winter, and winter plus spring responses. One application at the beginning of a two-year period was as effective as two annual dressings. Superphosphate applied with a wheat crop had a marked effect on the following ley pasture. It seems that superphosphate to meet the needs of short-term medic-barley grass pastures is best applied by increasing the dressing with the preceding cereal crop. Topdressing may be of greater value where cropping land is left out to pasture for longer periods. The pastures were also topdressed with zinc, copper, manganese, magnesium, molybdenum, and potassium for six years. They responded to zinc in two years, and to potassium in one year.