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Pasture Species (pasture + species)
Selected AbstractsWaterponding: Reclamation technique for scalded duplex soils in western New South Wales rangelandsECOLOGICAL MANAGEMENT & RESTORATION, Issue 3 2008Ray Thompson Summary Building on previous trials initiated in the 1960s, a demonstration programme involving 18 landholders was established at Nyngan, New South Wales Australia; in the mid-1980s to refine ,waterponding' techniques used to rehabilitate scalded claypans. The waterponding technique involves building horseshoe shaped banks (about 240 m in length) to create ponds of about 0.4 ha each. Each pond retains up to 10 cm of water after rain which leaches soluble salts from the scald surface. This improves the remaining soil structure, inducing surface cracking, better water penetration and allows entrapment of wind-blown seed. Consequently, niches are formed for the germination of this (and any sown) seed and recovery of a range of chenopod native pasture species occurs on the sites, which can be supplemented by direct seeding. What started as a project continues now as a standard rangeland rehabilitation process for reclaiming bare, scalded semi-arid areas of New South Wales and turning them back into biodiverse and productive rangelands. Since 1985, further modifications have been made to the method and the ongoing programme has surveyed, marked out and built approximately 56 700 waterponds within the Marra Creek waterponding district. [source] Semiarid land rehabilitation by direct drilling in the South Island, New Zealand,plant species and establishment technologyLAND DEGRADATION AND DEVELOPMENT, Issue 5 2004B. J. Wills Abstract Large areas of the east coast and inland basins of the South Island, New Zealand, are affected by periodic drought and/or semiarid climatic conditions, particularly during cyclic El Niño climatic events. The severity of these environmental conditions places great stress on introduced and native pasture species and frequently results in poor establishment of new pastures using standard drilling techniques. The objective of this study was to determine effective, practical means of rehabilitating semiarid land (about 470,mm annual rainfall) on a site in Central Otago. A comparison of two direct drilling methods, a novel strip-seeder drill and a standard hoe-coulter drill, was conducted in a trial initiated during spring 1998. Five drought-tolerant forage species were established: wheatgrass (Thinopyron intermedium), tall oat grass (Arrhenatherum elatius), birdsfoot trefoil (Lotus corniculatus), hairy dorycnium (Dorycnium hirsutum) and bluebush (Kochia prostrata). For the 2000/2001 growing season, species established with the strip-seeder drill had an overall mean herbage biomass of 235,g,m,,2,, three-times that for the hoe-coulter drill (77,g,m,,2,, P,<,0·001). Differences in herbage biomass between species were observed, with hairy dorycnium (mean 328,g,m,,2,) producing significantly (P,<,0·001) more herbage biomass than the other species. After the third spring, the percentage ground cover recorded from transects across the strip-seeder drill plots (cf. the hoe-coulter drill) was: wheatgrass,41,per,cent (10,per,cent); tall oat grass,44,per,cent (25,per,cent); birdsfoot trefoil,25,per,cent (5,per,cent); hairy dorycnium,50,per,cent (19,per,cent); and bluebush,4,per,cent (0,per,cent). The native plant content of the resident vegetation was reduced as a result of the drilling treatments and also when fertilizer was added to undistrubed pasture. The strip-seeder drill is capable of providing superior plant growth on dryland sites even during adverse drought conditions. It produces a furrow approximately 16,cm wider than the hoe-coulter drill, exerts a greater shattering effect on the soil structure and places fertilizer at depth. It is suggested that this assists plant establishment by providing good seedling protection from wind and sun, and subsequent plant growth by allowing easier root penetration to the subsoil where nutrients and moisture are available. Copyright © 2004 John Wiley & Sons, Ltd. [source] Sustainable production of crops and pastures under drought in a Mediterranean environmentANNALS OF APPLIED BIOLOGY, Issue 2 2004NEIL C TURNER Summary Mediterranean environments are characterised by cool wet winters and hot dry summers. While native vegetation in Mediterranean-climatic zones usually comprises a mixture of perennial and annual plants, agricultural development in the Mediterranean-climatic region of Australia has led to the clearing of the perennial vegetation and its replacement with annual crops and pastures. In the Mediterranean environments of southern Australia this has led to secondary (dryland) salinisation. In order to slow land degradation, perennial trees and pasture species are being reintroduced to increase the productivity of the saline areas. The annual crops and pastures that form the backbone of dryland farming systems in the Mediterranean-climatic zone of Australia are grown during the cool wet winter months on incoming rainfall and mature during spring and early summer as temperatures and rates of evaporation rise and rainfall decreases. Thus, crop and pasture growth is usually curtailed by terminal drought. Where available, supplementary irrigation in spring can lead to significant increases in yield and water use efficiency. In order to sustain production of annual crops in Mediterranean environments, both agronomic and genetic options have been employed. An analysis of the yield increases of wheat in Mediterranean-climatic regions shows that there has generally been an increase in the yields over the past decades, albeit at a lower rate than in more temperate regions. Approximately half of this increase can be attributed to agronomic improvements and half to genetic improvements. The agronomic improvements that have been utilised to sustain the increased yields include earlier planting to more closely match crop growth to rainfall distribution, use of fertilisers to increase early growth, minimum tillage to enable earlier planting and increase plant transpiration at the expense of soil evaporation, rotations to reduce weed control and disease incidence, and use of herbicides, insecticides and fungicides to reduce losses from weeds, insects and disease. Genetic improvements include changing the phenological development to better match the rainfall, increased early vigour, deeper rooting, osmotic adjustment, increased transpiration efficiency and improved assimilate storage and remobilisation. Mediterranean environments that are subjected annually to terminal drought can be both environmentally and economically sustainable, but to maximise plant water use efficiency while maintaining crop productivity requires an understanding of the interaction between genotypes, environment and management. [source] Is there a relationship between herbaceous species richness and buffel grass (Cenchrus ciliaris)?AUSTRAL ECOLOGY, Issue 5 2005JANICE JACKSON Abstract Cenchrus ciliaris L. (buffel grass) (Poaceae) is recognized as one of Australia's most serious environmental weeds. This introduced grass has been associated with loss of native species and alteration of fire regimes. However, it is also highly valued as a pasture species for arid and semiarid zones and its weed status is highly controversial. Quantitative studies are needed to determine its ecological effects. The relationship between C. ciliaris and herbaceous species richness was investigated in two studies at a range of scales up to 64 m2 in open woodlands in the Dalrymple Shire, north-eastern Queensland. In the first study, the herbaceous species composition of sites with and without C. ciliaris were compared. Cenchrus ciliaris -dominated sites had fewer herbaceous species than non- C. ciliaris sites at all scales investigated and this pattern was found for the major plant groups (perennial grasses, legumes and other forbs) present. In the second study, the relationship between varying levels of C. ciliaris biomass and species richness was investigated. The relationship between varying levels of a dominant native grass, Bothriochloa ewartiana (Domin) C.E. Hubb. (Poaceae), and species richness was also determined for comparison with the C. ciliaris biomass-richness relationship. In this study, species richness was negatively associated with increasing C. ciliaris biomass at some scales and it appeared that C. ciliaris had a greater effect on richness than B. ewartiana. The negative association between C. ciliaris and species richness is consistent with the view that invasion by C. ciliaris poses a threat to biodiversity. However, the precise cause of the relationship has yet to be determined. [source] Responses of ant communities to experimental fire regimes on rangelands in the Victoria River District of the Northern TerritoryAUSTRAL ECOLOGY, Issue 2 2003BENJAMIN D. HOFFMANN Abstract Fire is a significant feature of Australia's savannas. Its use is being encouraged for cattle rangeland management, but there is little knowledge of the ecological effects of prescribed fire regimes on native biodiversity. The responses of ant communities to five experimental fire regimes over 2 years are reported from the Victoria River District in the semi-arid tropics of northern Australia. The experiment was stratified at two levels: soil type (red and black) and fire treatment (unburnt; burnt twice in successive years in early (May) or late (October) dry season and unburnt thereafter; and burnt twice, 3 years apart, in early or late dry season). Ants were sampled twice in April, corresponding with the end of the 1997 and 1998 wet seasons. Ant species richness was not responsive to fire treatment, but reduced with time since fire on black soil. Total ant abundance also reduced with time since fire on the black soil, with significant different abundances in burnt versus unburnt plots in the 1998 sample. Soil type and sampling time had the greatest influence on ant community composition in multivariate analysis than did fire regime, although there were moderate gradients of time since fire with the black soil plots. The abundance of 19 species were significantly different between fire regimes in ANOVA, 13 on red soil and six on black soil. The abundance of eight species (four each on red and black soil) changed significantly with time since fire, with seven promoted by burning. Ant functional group profiles changed little with fire. Total ant abundance and richness had significant relationships with key pasture species and vegetative variables. The responses of ants largely recapitulated those of plants, birds and reptiles on the same plots. It is envisaged that ants will have an important role to play in the sustainable management of Australia's rangelands aiding the off-reserve conservation of biodiversity. [source] | ||||||||||