Grazing Impacts on Spatial Distribution of Soil and Herbaceous Characteristics in an Australian Tropical Woodland

TitleGrazing Impacts on Spatial Distribution of Soil and Herbaceous Characteristics in an Australian Tropical Woodland
Publication TypeJournal Article
Year of Publication2005
AuthorsNorthup B.K., Brown J., Ash A.J.
JournalAgroforestry Systems
Date Published2005
ARIS Log Number164100
KeywordsEucalypt woodlands, grazing pressur, land condition, plant-soil interactions, silvopasture, soil properties
AbstractLand condition in northern Australia can be easily degraded by grazing or grazing in combination with drought. These areas require the use of grazing systems that allow persistence of native tussock grasses, and maintenance of soil condition. However, there is little information available on best level of utilization, or how plants and soils will respond to grazing and drought. This study examined effects of six different grazing regimes (based on timing and grazing intensity), applied over five (n=4) and 15 (n=2) years, on herbaceous vegetation (standing crop, basal area, size and spacing of grass tussocks) and soil properties (soil C, total N, total P, and soil-borne plant matter [roots and surface litter]) around grass tussocks in replicate (n=2) paddocks of eucalypt woodland in northern Queensland. Grass tussocks influenced soil C and total N at small (<30 cm) spatial scales, and applied grazing pressures significantly (P<0.05) affected all soil properties except total P. Concentrations of N and C were highest at locations in close proximity to plants, and levels declined under heavier grazing pressures. These paddocks also had less standing crop, smaller tussocks, and more widely dispersed surviving plants. Further, areas with high amounts of soil C, N and roots-litter were smaller and more widely dispersed under heavy grazing. North Australian landscapes have limited resistance to disturbance, or resilience available for recovery. As such, the effects of disturbance should be monitored by a combination of plant (basal area, plant spacing) and soil characteristics (total N, soil borne plant matter) that can detect the degradation process at the earliest stage possible.