THE SOIL CONDITION OF ADJACENT BIODYNAMIC AND CONVENTIONALLY MANAGED DAIRY PASTURES IN VICTORIA, AUSTRALIA

Physical and chemical properties were compared during 1992 in adjacent bio-dynamic and conventionally managed Haploxeralfs under improved, summer-irrigated pastures in the Goulburn Valley of N.E. Victoria. Intensive dairy production has been practised on both the farms since the early 1950s, and aspects of the bio-dynamic method have been practised on one farm for the past 18 years. Particle-size analysis showed that the soil profiles of each field are derived from similar parent materials. The bio-dynamic soil had greater macro-porosity to a depth of at least 420 mm, lesser soil strength at 60, 120 and 200 mm, smaller dry bulk density values between 120 and 200 mm and larger organic matter content in the upper 50 mm. Volumetric soil water content measured along three transects to a depth of 1.4 m in the summer showed that the bio-dynamic field was drier at depths greater than 200 mm. After heavy rains during the winter, the conventionally managed soil had an air-filled porosity unfavourable for plant roots (2%) at 200 mm depth, whereas the bio-dynamic soil was marginal for root growth (7%). The more favourable physical and chemical properties in the bio-dynamic soil may be attributed to less grazing pressure, longer intervals between irrigations, use of the bio-dynamic horn-manure preparation, intermittent compost applications, less tractor traffic and the encouragement of taller pasture growth.