Effects of grazing and management on herbage mass, persistence, animal production and soil water content of native pastures. 2. A mixed native pasture, Manilla, North West Slopes, New South Wales

Abstract

As part of the Sustainable Grazing Systems (SGS) National Experiment a study was conducted on a native pasture in the Manilla district of northern New South Wales to examine the effects of 5 grazing treatments on total herbage mass, litter mass, basal cover, ground cover, sheep liveweight, wool production and soil water content (SWC, mm) at different depths. The pasture was a mixture of native perennial grasses, with redgrass (Bothriochloa macra) and wiregrass (Aristida ramosa) dominant on a red Chromosol soil type and bluegrass (Dichanthium sericeum) on a brown Vertosol. Wallaby grasses (Austrodanthonia richardsonii and A. bipartita) were common on both soils. Plots were grazed with Merino wethers and data collected from spring 1997 to spring 2001 were analysed to determine the effect of treatments on both production and sustainability. Five grazing treatments were applied in a randomised 3 replicate design. Grazing treatments were: continuous grazing at 3.1 and 6.2 sheep/ha (C3 and C6), continuous grazing at 9.2 sheep/ha, with subterranean clover (Trifolium subterraneum) oversown and fertiliser applied (C9+sub) and rotational grazing at an annual stocking rate of 3.1 sheep/ha with pasture grazed for 4 weeks and rested for 4 weeks (R4/4), or rested for 12 weeks (R4/12).Over time, treatments had no significant effect on either total pasture herbage mass (compared with the C3 control) or the basal cover of the major perennial grasses. Treatments had inconsistent significant effects on ground cover, litter mass, sheep liveweight and wool production (kg/head) over time. Compared with all other treatments ground cover was less (P<0.05) in the C6 treatment in only May and September 2000 and litter mass less (P<0.05) in only December 1998 and March 1999. Treatment sheep liveweights were not significantly different from the C3 treatment sheep liveweight in the C6 treatment was significantly less than in the C3 treatment, while in the C9+sub and R4/12 treatments it was significantly greater than the control. In 1999, wool production per head was higher (P<0.05) in the C9+sub and R4/12 treatments compared with all other treatments but treatment differences were not significant in all other years. Significant differences in SWC only occurred at the 0-30 cm depth between the C3 and the C6 and R4/12 treatments, but were predicted to be <1.5 mm/year. A sustainability index derived from economic [equivalent annual net return ($/ha) for a 10-year period], animal production, pasture, soil health and soil water data indicated that the overall indices were lowest for the C3, C6 and C9+sub treatments and highest for the R4/4 and R4/12 treatments. H e r b a g e , a n i m a l p r o d u c t i o n a n d s o i l w a t e r c o n t e n t o f n a t i v e p a s t u r e s . 2 Australian Journal of Experimental Agriculture G. M. Lodge et al.

Potential Distribution of the Australian Native Chloris truncata Based on Modelling Both the Successful and Failed Global Introductions

“…Information on the current distribution of C. truncata was obtained from a wide range of literature sources [4] , [5] , [7] , [10] , [14] , [19] , [21] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] and online databases (GBIF [43] , Australian Virtual Herbarium (AVH) [44] , TROPICOS [45] , Germplasm Resources Information Network (GRIN) [46] , South African National Biodiversity Institute (SANBI) [47] , Consortium of California Herbaria [48] , New Zealand Virtual Herbarium [49] , Bernice Pauahi Bishop Museum [50] , National Museum of Natural History [51] ) using the currently accepted name of the species and any other species level synonyms as listed in the Australian Plant Name Index [52] . Following data proofing, there were 1237 valid and 28 invalid records in Australia, and 138 valid and 25 invalid records for the rest of the world.…”

Towards Sustainable Land Use in Vertisols in Kenya: Challenges and Opportunities

“…The situation is made worse by the impact of grazing animals on the soil's physical properties (Devendra and Thomas, 2002;Taddese et al, 2002;Lodge et al, 2003;Wanyoike and Wahome, 2004). Vertisols are highly pre-disposed to rill and gulley erosion in areas with slope ≥2% due to poor infiltration (Probert et al, 1987).…”

“…In the system, as in many others, development of management and cropping systems that enhance and maintain land productivity is essential. Studies in Australia indicated that the best land quality could be achieved from low to medium stocking rates combined with field resting for 4 or 12 weeks, based on a sustainability index from data on animal production, pasture, soil health and soil water (Lodge et al, 2003).…”

Testing and evaluating large-scale agricultural simulation models

“…However, as well as having lower rainfall, Moree also is considerably hotter. The model has been run for a generic native C 3 / C 4 pasture, such as wallaby grass and redgrass, typical of this region (Lodge et al, 2003), and set-stocked with wethers with a normal mature body weight of 60 kg. In practice there will be a mixture of species, and this is discussed later.…”