Establishment of green panic as influenced by type, amount, and placement of vegetative mulch

Abstract

Establishment of green panic (Panicum maximum var, trichoglume cv. Petrie), was measured after sowing beneath mulches of sawdust, native pasture hay, barley straw, Dolichos lablab stubble and sorghum stubble. Long, chaffed, or milled materials, all applied at 2500, 5000, or 10,000 kg ha-1 were tested. Comparisons were made with a control (no mulch) in two experiments on a self-mulching clay at Gayndah, south-eastern Queensland. Seedling emergence with all surface mulches was superior to the control and to emergence from sowing into mulch incorporated in the surface soil. Optimum rates of mulch for emergence approached 5000 kg ha-1 but varied between experiments and with mulch types. Reducing mulch particle size did not consistently improve emergence relative to long straw. In a third experiment, seedling emergence at 42 days after irrigation was directly related to the proportion of area covered by mulch irrespective of the arrangement of mulch bands. Seedling yield followed trends in plant density. Practical implications of the results are discussed.