Evaluation of native and introduced grasses for low-input pastures in temperate Australia: rationale and scope

2005 ◽  
Vol 27 (1) ◽  
pp. 1 ◽  
Author(s):  
R. D. B. Whalley ◽  
D. A. Friend ◽  
P. Sanford ◽  
M. L. Mitchell
Keyword(s):  
Arid Regions ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
High Input ◽  
Low Input ◽  
Evaluation Phase ◽  
Site Evaluation ◽  
Broad Objective ◽  
Evaluation Project ◽  
Semi Arid

The historical approach to pasture improvement in the high rainfall zone of temperate Australia has been to add introduced herbaceous legumes and to replace perennial native grasses with introduced species requiring high inputs of fertiliser for maintenance. The application of this high-input approach on land with low capability has lead to the loss of perennial grasses, erosion, soil acidification and increasing salinity on the lower slopes. This model of pasture improvement has not been successful on the margins of the wheat belt and in semi-arid regions. The Native and Low-input Grasses Network (NLIGN) was established in 1996 to coordinate research on grasses suitable for land with low capability and for semi-arid regions. The NLIGN multi-site evaluation project was initiated to test promising lines (accessions) of native and introduced grasses for low-input pastures at eight sites across southern Australia. The broad objective of the project was to identify native and/or introduced perennial grass lines that had possible commercial potential for low-input pastures. This objective was achieved in an initial 3-year evaluation phase, which began in 1998 and tested lines for persistence, production and palatability.

The Influence of Recent Grazing Pressure and Landscape Position on Grass Recruitment in a Semi-Arid Woodland of Eastern Australia.

1996 ◽  
Vol 18 (1) ◽  
pp. 3 ◽  
Author(s):  
VJ Anderson ◽  
KC Hodgkinson ◽  
AC Grice
Keyword(s):  
Seedling Emergence ◽  
Perennial Grass ◽  
Soil Surface ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Run Off ◽  
Eastern Australia ◽  
Annual Grasses ◽  
History Of ◽  
Semi Arid

This study examined the effects of previous grazing pressure, position in the landscape and apparent seed trapping capability of soil surface micro-sites on recruitment of the perennial grass Monachather paradoxa (mulga oats) in a semi-arid woodland. Seedling emergence was counted on small plots which had been kept moist for one month. The plots were on bare ground, or at grass tussocks, or at log mounds, sited in the run-off, interception and run-on zones of paddocks that had been grazed for six years at 0.3 and 0.8 sheep equivalent/ha. Few naturally occurring perennial grass seedlings emerged on any of the sites. The level of previous grazing pressure influenced the recruitment of grasses from natural sources as well as from seed of M. paradoxa broadcast on the soil surface; significantly more grass seedlings recruited in paddocks stocked at 0.3 than at 0.8 sheep/ha. Emergence of the sown grass did not differ significantly between the three zones in the landscape, but trends in the data suggest the interception zone may have been the most favourable. Recruitment from in situ grass seed was highest in the mulga grove (run-on) zone. Most seedlings of the sown grass emerged around the bases of existing perennial grass tussocks, but recruitment of volunteer perennial and annual grasses was more evenly distributed between the mulga log-mounds and perennial grass tussocks. It is concluded that very low levels of readily germinable seed of perennial grasses remained in the soil at the end of the drought and that areas with a history of high grazing pressure have less probability of grass recruitment when suitable rain occurs.

Managing competitive interactions to promote regeneration of native perennial grasses in semi-arid south-eastern Australia

2017 ◽  
Vol 39 (1) ◽  
pp. 59
Author(s):  
Ronald B. Hacker ◽  
Ian D. Toole ◽  
Gavin J. Melville ◽  
Yohannes Alemseged ◽  
Warren J. Smith
Keyword(s):  
Weed Control ◽  
Biomass Production ◽  
Soil Nitrogen ◽  
Perennial Grass ◽  
Perennial Grasses ◽  
Soil Nitrate ◽  
Nitrogen Reduction ◽  
Eastern Australia ◽  
Semi Arid ◽  
Native Perennial Grass

Treatments to reduce available soil nitrogen and achieve specified levels of weed control were evaluated for their capacity to promote regeneration of native perennial grasses in a degraded semi-arid woodland in central-western New South Wales. Treatments were factorial combinations of nitrogen-reduction levels and weed-control levels. The four levels of nitrogen reduction were no intervention, and oversowing of an unfertilised summer crop, an unfertilised winter crop or an unfertilised perennial grass. The three weed-control levels were defined by the outcome sought rather than the chemical applied and were nil, control of annual legumes and control of all annual species (AA). Regeneration of perennial grasses, predominantly Enteropogon acicularis, was promoted most rapidly by the AA level of weed control with no introduction of sown species. Sown species negated the benefits of weed control and limited but did not prevent the regeneration of native perennials. Sown species also contributed substantially to biomass production, which was otherwise severely limited under the AA level of weed control, and they were effective in reducing soil nitrogen availability. Sown species in combination with appropriate herbicide use can therefore maintain or increase available forage in the short–medium term, permit a low rate of native perennial grass recruitment, and condition the system (by reducing soil mineral nitrogen) for more rapid regeneration of native perennials should annual sowings be discontinued or a sown grass fail to persist. Soil nitrate was reduced roughly in proportion to biomass production. High levels of soil nitrate did not inhibit native perennial grass regeneration when biomass was suppressed by AA weed control, and may be beneficial for pastoral production, but could also render sites more susceptible to future invasion of exotic annuals. The need for astute grazing management of the restored grassland is thus emphasised. This study was conducted on a site that supported a remnant population of perennial grasses. Use of the nitrogen-reduction techniques described may not be appropriate on sites where very few perennial grass plants remain.

Changes in Grass Density in Australian Semi-Arid Woodlands.

1995 ◽  
Vol 17 (1) ◽  
pp. 26 ◽  
Author(s):  
AC Grice ◽  
I Barchia
Keyword(s):  
Perennial Grass ◽  
Perennial Grasses ◽  
Grass Species ◽  
European Settlement ◽  
Eastern Australia ◽  
Rate Of Response ◽  
Semi Arid

Changed grazing regimes since European settlement have been widely proposed as the cause of a decline of indigenous perennial grasses in the semi-arid woodlands of eastern Australia. A five year experiment using exclosures examined the effects of grazing on densities of perennial grasses. Short- lived Stipa spp. and Aristida spp. were dominant at most sites. Their densities fluctuated greatly with season and reached over 200 plants/m2 during climatically favourable periods. The long-lived Eragrostis eriopoda occurred at densities that were generally less than 5 plants/m2 and its populations were relatively stable. The response of Enneapogon avenaceus was distinctive. Though its density fluctuated considerably, successive peaks in density were higher and the species increased more in ungrazed areas than in destocked or unfenced areas. The differences between grazed and ungrazed populations became greater with successive peaks in density. Within the short periods that pastoralists are likely to be willing or able to apply such treatments, destocking or even removing all herbivores is unlikely to have a large effect on the density of many palatable perennial grass species. The rate of response to resting pastures will depend on seasonal conditions.

Temporary cropping in semi-arid shrublands increases native perennial grasses

2011 ◽  
Vol 33 (1) ◽  
pp. 67 ◽  
Author(s):  
Y. Alemseged ◽  
R. B. Hacker ◽  
W. J. Smith ◽  
G. J. Melville
Keyword(s):  
Perennial Grass ◽  
Stable State ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Grazing Management ◽  
Alternative Stable State ◽  
Pasture Production ◽  
Native Grasslands ◽  
Native Shrubs ◽  
Semi Arid

Thickening of native shrubs is a major problem in many ‘semi-arid woodlands’ as significant increase in shrub density is often negatively correlated with herbaceous vegetation and leads to reduced pasture production and soil erosion. This project aimed to test the hypothesis that temporary cropping (up to three crops in 15 years) consistently increases the density of native perennial grasses following the removal of shrubs. A total of 30 paddocks that had been cropped during the last 20 years were randomly selected using a satellite-based database that documented annual clearing and cropping history from 1987 to 2003. Paddocks were classified into four types based on clearing and cropping history and grazing management – not cleared (shrubs), regrowth (re-invaded by shrubs), set stocked (cropped and grazed), light/rotationally grazed (cropped and grazed). The responses of vegetation and soil (chemical and physical) properties to clearing and cropping were evaluated. Results indicated that ground cover, native perennial grass cover and standing dry matter were highest under light/rotationally grazed conditions. The shrub state represents a stable state within the Cobar pediplain brought about due to land-use change in the form of overgrazing and/or the removal of fire from the system. An alternative stable state was achieved as a result of disturbance in the form of clearing, cropping and grazing management thereby directly altering the shrub population. The resilience of this state is largely dependent on the grazing management system used and on the prevention of shrub from re-establishing while failure to control shrubs could lead to the re-emergence of the Shrub State. We conclude that native grasslands do regenerate following cropping after removal of shrubs. The importance of grazing management for restoring perennial ground cover following removal of shrubs and temporary cropping has been clearly demonstrated by the study.

Effects of nitrogen and phosphorus on vegetation dynamics of a degraded native grassland in semi-arid south-eastern Australia

2011 ◽  
Vol 33 (1) ◽  
pp. 87 ◽  
Author(s):  
R. B. Hacker ◽  
I. D. Toole ◽  
G. J. Melville
Keyword(s):  
Vegetation Dynamics ◽  
Plant Density ◽  
Perennial Grass ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Grass Species ◽  
Nitrogen And Phosphorus ◽  
Mineral N ◽  
Eastern Australia ◽  
Semi Arid

The roles of nitrogen (N) and phosphorus (P) in controlling vegetation transitions in a degraded semi-arid grassland were investigated in a factorial experiment that combined two initial levels of perennial plant density (low and high), three levels of N (N+, N0 and N–) and two levels of P (P+ and P0). Increased levels of both N and P were achieved by fertiliser addition while sucrose was used to reduce the level of N. Vegetation dynamics were driven primarily by soil N rather than P. Addition of sucrose, which was inferred to result in the immobilisation of mineral N, reduced the growth of annual species and facilitated the establishment and growth of native perennial grasses. Addition of P generally had no significant effect on dry matter production, either in total or for species grouped as forbs, annual grasses and perennial grasses, or on recruitment and mortality of perennial grasses. However, at some times of observation addition of P increased ground cover and/or the basal circumference of some perennial grass species. Basal circumference for Enteropogon acicularis was also increased by addition of N. Soil biological activity, measured by decomposition of cotton strips, was increased by addition of N, which maintained vegetation in an annual-dominated condition, and was not affected by addition of P. Carbon addition has the potential to assist restoration of this grassland. However, the capacity of some native grass species to respond to increased fertility suggests that once restoration is achieved some increase in fertility may be beneficial for pastoral production.

Spatial and Temporal Pattern in the Grazing of Grasses by Sheep Within a Semi-Arid Wooded Landscape.

1995 ◽  
Vol 17 (2) ◽  
pp. 154 ◽  
Author(s):  
KC Hodgkinson ◽  
JW Terpstra ◽  
WJ Muller
Keyword(s):  
Woody Plant ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Perennial Grasses ◽  
Spatial And Temporal Variation ◽  
Grass Species ◽  
Plant Mortality ◽  
Research Facility ◽  
Semi Arid ◽  
Domestic Stock

Grazing the woodlands of semi-arid and arid Australia by domestic stock has extensively collapsed perennial *grass populations and thereby fostered woody plant increase. This study examined the pattern of grazing of individual grass plants by sheep in the landscape of a semi-arid woodland, and a model was developed describing the spatial and temporal influences on the grazing pressure placed on plants. Plants of two widespread perennial grass species differing in palatability, Eragrostis eriopoda and Thyridolepis mitchelliana, were examined weekly in two contrasting periods at the CSIRO Lake Mere Research Facility. The plants were located throughout the landscape in lightly- and heavily- stocked paddocks. Patterns of grazing in space and time were determined by examining the grazing of marked tillers. No preference was shown for previously ungrazed plants and only occasionally were previously grazed plants preferred. Thyridolepis mitchelliana plants were slightly preferred over E. eriopoda plants. Landscape zones receiving water and nutrients from elsewhere were preferred for grazing but the effect was weak. The foliage biomass of herbaceous plants in the immediate vicinity of a grass plant did not influence the number of tillers grazed nor the probability of the plant being grazed. Overall the defoliation of individual plants by sheep was weakly determined by landscape location, stocking level, plant species and prevailing forage on offer. The influence of spatial and temporal variation was small; random grazing of grass plants was the rule. This finding suggests that the grazing pressure on palatable perennial grasses in the paddocks of semi-arid woodlands will be similar across wooded landscapes and that spatial variability in plant mortality could be due to. the combined effect of plant water stress, which varies spatially and temporally, and grazing pressure which varies temporally but not spatially.

scholarly journals Low-input cultivation of camelina (Camelina sativa (L.) Crantz) in a Mediterranean semi-arid environment

2021 ◽  
Author(s):  
Giovanni Avola ◽  
Orazio Sortino ◽  
Fabio Gresta
Keyword(s):  
Crop Residues ◽  
Conservation Agriculture ◽  
Arid Environment ◽  
Fertilization Rate ◽  
Camelina Sativa ◽  
Point Of View ◽  
Biofuel Production ◽  
High Input ◽  
Low Input ◽  
Semi Arid

The cultivation of oil crops for biofuel production has often been accused of not being environmentally sustainable due to the high inputs needed. To explore the effect of reduced input on productive and qualitative traits of camelina (Camelina sativa (L.) Crantz), a trial was carried out over a two-year period. This study analyzed two different levels of input: a low input treatment (shallow non-inversion tillage and low fertilization rate) and a high input treatment (deeper tillage and high fertilization rate). Camelina was positively, even though to a limited extent, affected by high input treatment as highlighted by the increase in seed yield (from 1.8 to 2.0 t ha-1), crop residues (from 4.8 to 5.2 t ha- 1), seed protein content (from 26.5 to 28.9%), seed oil content (from 41.5 to 43.4%) and oil yield (from 0.75 to 0.88 t ha-1). So, from a sustainable point of view, we must consider negligible the effect of high input and satisfactory the performances of camelina in the low input regime. Low input management resulted in satisfactory yields in terms of both quantity and quality, results which were not very different from high input, indicating promising potential for conservation agriculture practices in camelina in a semi-arid environment.

scholarly journals Characterization and discovery of miRNA and miRNA targets from apomictic and sexual genotypes of Eragrostis curvula

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Ingrid Garbus ◽  
Juan Pablo Selva ◽  
María Cielo Pasten ◽  
Andrés Martín Bellido ◽  
José Carballo ◽  
...  
Keyword(s):  
Small Rna ◽  
Small Rnas ◽  
Arid Regions ◽  
Perennial Grass ◽  
Differential Expression Analysis ◽  
Sandy Soils ◽  
Ploidy Levels ◽  
Eragrostis Curvula ◽  
Sexual Repression ◽  
Semi Arid

Abstract Background Weeping lovegrass (Eragrostis curvula [Shrad.] Nees) is a perennial grass found in semi-arid regions that is well adapted for growth in sandy soils and drought conditions. E. curvula constitutes a polymorphic complex that includes cytotypes with different ploidy levels (from 2x to 8x), where most polyploids are facultative apomicts, although both sexual reproduction and full apomixis have been reported in this species. Apomixis is thought to be associated with silencing of the sexual pathway, which would involve epigenetic mechanisms. However, a correlation between small RNAs and apomixis has not yet been conclusively established. Results Aiming to contribute to the elucidation of their role in the expression of apomixis, we constructed small RNA libraries from sexual and apomictic E. curvula genotypes via Illumina technology, characterized the small RNA populations, and conducted differential expression analysis by comparing these small RNAs with the E. curvula reference transcriptome. We found that the expression of two genes is repressed in the sexual genotype, which is associated with specific microRNA expression. Conclusion Our results support the hypothesis that in E. curvula the expression of apomixis leads to sexual repression.

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