Grazing management and its effects on groundcover and runoff control in Queensland, Australia
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Grazing animals affect pasture properties by altering plant cover as well as physical impact of their hooves. Reduction in vegetation cover may increase the effect of raindrops and consequently decrease water infiltration rates result in increased runoff and soil degradation. It is largely assumed that rest period in grazing land can improve ground cover and so grass production through providing opportunities for maintaining plant vigor, seeding and seedling establishment and better sheep distribution ultimately decreasing runoff and sediment losses. However, application of rest period in the grazing management of some geographic locations have not supported this idea that rest period always leads to a higher vegetation level, and lower runoff. Study area (Traprock region of Queensland) with 580 mm rainfall located in semiarid part of subtropical zone, is a sheep grazing area with poor soil. Graziers in this region are concerned about the long term productivity and the impact of current grazing practices on their land and water resources, so in this research Time controlled grazing system which is a flexible rotational grazing with large period of rest is compared with conventional grazing system (a continuous grazing without rest). This comparison is based on massive pasture sampling and runoff data collection using two large instrumented plots initiated in 2001 to address the questions raised regarded to sustainable productivity and soil degradation. In spite of drought governing over the past 4 years, initial results illustrate higher production and ground cover as well as lower runoff and sediment losses in Time controlled research paddocks compared with Conventional. In this case, relationship between vegetation and effective rainfall shows the Time controlled is more responsive to available moisture than Conventional. This improvement in cover and consequently decline in runoff volume is attributed to expansion of root growth over the rest period resulting in building up soil organic matter which in turn increases biological activity.
Water Management and Soil Conservation in Semi-arid Environments.
© 2006 International Soil Conservation Organisation.