Influence of stocking rate and phosphate fertiliser application on the composition of annual legume seedbanks within a Mediterranean grassland

2010 ◽  
Vol 61 (12) ◽  
pp. 988 ◽  
Author(s):  
Hayley C. Norman ◽  
Philip S. Cocks ◽  
Nicholas W. Galwey
Keyword(s):  
Reproductive Strategies ◽  
Grazing Intensity ◽  
Common Garden ◽  
Stocking Rate ◽  
Legume Seed ◽  
Early Maturity ◽  
General Hypothesis ◽  
High Fecundity ◽  
Phosphate Fertiliser ◽  
Fertiliser Application

This paper tested the general hypothesis that differences in grazing intensity and phosphate application lead to adjustments in the structure of an annual legume community in natural and diverse grassland at Tel Hadya, Syria, due to changes in competitive relationships between species. The management treatments imposed were a factorial design of 0 or 60 kg/ha of superphosphate fertiliser (applied annually) and relatively low or high continuous sheep stocking intensities. These management treatments were applied for 13 years across three replicate paddocks for each treatment before the annual legume seed banks were sampled. The seed was sorted and representative plants were grown in a common garden in Perth, Australia, to assess reproductive and morphological traits. We found that phosphate application had more influence on species composition than stocking rate and favoured species with relatively competitive reproductive strategies (plants with relatively large seeds, low fecundity and early maturity). Contrary to our expectations, a higher stocking rate did not result in an increase in the proportion of small seeds in the legume seed bank or favour species with other strongly ruderal-type reproductive strategies (high fecundity and high seed dormancy). In paddocks without phosphate application, the high and low stocking rate paddocks were dominated by different species (Trifolium tomentosum and T. campestre), each with a similar reproductive strategy. Plant architecture and/or differences in animal selectivity may account for these differences. The study highlights the importance of phosphate fertiliser for maintaining seedbanks of competitive-type (large seed size, highly productive with good early vigour) annual legume species.

Gross margins in Australian mohair enterprises and relationships with farm inputs, productivity and mohair quality

2010 ◽  
Vol 50 (6) ◽  
pp. 573 ◽  
Author(s):  
B. A. McGregor ◽  
W. D. English
Keyword(s):  
Grazing Intensity ◽  
Financial Information ◽  
Average Price ◽  
Stocking Rate ◽  
Fine Hair ◽  
Gross Margin ◽  
Phosphate Fertiliser ◽  
Eastern Australia ◽  
Gross Margins ◽  
Farm Inputs

In the absence of financial information on Australian mohair enterprises we aimed to determine the gross margins (per dry sheep equivalent, DSE) and their relationships with farm inputs, productivity and mohair quality in Australian mohair enterprises. Using established Victorian Farm and Sheep Monitor Project protocols we collected data for the financial years 2004–05, 2005–06 and 2006–07 from farmers in south-eastern Australia and made comparisons with data from wool enterprises of similar farm area. Over 3 years the financial returns from mohair exceeded that from wool in terms of $/DSE ($23.0 v. 11.3) and $/ha ($132 v. $116). This result was achieved despite the mohair enterprises grazing their goats far less intensively compared with the grazing intensity of sheep (5.9 v. 10.3–11.1 DSE/ha) and by using far less phosphate fertiliser than used in the wool enterprises (2.2 v. 4.6–6.1 kg P/ha). These differences were counterbalanced by higher prices for mohair compared with fine wool ($13.15/kg v. $8.35/kg clean fibre). Gross margin for the mohair enterprise did not increase as stocking rate increased. Income from mohair sales declined as the proportion of does in the flock increased. Increasing the proportion of does in the flock was associated with a decline in the average price of mohair ($16/kg greasy at 42% does to $8/kg greasy at 83% does in the flock). This decline was closely associated with the increasing proportion of the total amount of mohair coarser than 34.0 µm (either fine hair or hair) plus stained mohair. The variation in profitability between farms indicates significant scope for many mohair enterprises to increase profit. A focus on producing finer quality mohair will increase mohair profitability.

Increasing ewe genetic fecundity improves whole-farm production and reduces greenhouse gas emissions intensities: 2. Economic performance

2014 ◽  
Vol 54 (9) ◽  
pp. 1248 ◽  
Author(s):  
C. K. M. Ho ◽  
T. Jackson ◽  
M. T. Harrison ◽  
R. J. Eckard
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Net Present Value ◽  
Stocking Rate ◽  
Present Value ◽  
Gas Emissions ◽  
High Fecundity ◽  
Farm Profit ◽  
Baseline System

Ewes with the fecundity Booroola (FecB) gene produce more lambs per ewe on average than ewes without the gene and offers a potential way to decrease greenhouse gas emissions (net and per unit animal product) without reducing lamb production if the lambs can be reared to market weights. Using a case study farm in south-west Victoria, a biophysical modelling study has previously showed that increased ewe fecundity from 1 to 1.5 lambs per ewe increased production by 27% and reduced net farm emissions by 21% for the same long-term stocking rate. In this study, a whole-farm economic analysis was used to investigate the relative merit of the same case study farm, with high-fecundity ewes, compared with a baseline system that represented a typical prime lamb enterprise in the region. An additional system comprising ewes with high fecundity at a lower stocking rate than the case study farm was also examined. The analysis was undertaken to establish which farm systems represented the most economically efficient use of all the resources that are employed over a run of years, and involved estimating the net present value of annual profits earned by the farm in each scenario, taking into account the total value of capital used. The potential revenue from the sale of carbon credits through the Carbon Farming Initiative was also investigated. After accounting for the additional costs involved, increasing ewe fecundity resulted in an increase in annual whole-farm profit compared with the baseline system, but risk, considered as the variability in farm profit, also increased. Decreasing stocking rate for the high-fecundity system reduced annual operating profit and net present value at a 5% discount rate, but had less risk compared with the higher stocking rate system. While both systems that incorporated high-fecundity ewes reduced greenhouse gas emissions, revenue from the sale of carbon credits was small compared with revenue from the sale of lambs, wool and culled ewes. Despite this, and assuming the required increases in fertility and weaning rates could be achieved consistently on-farm, ewes with high fecundity may offer producers the opportunity to increase production and profit as well as decrease greenhouse gas emissions.

Assessing the intrinsic resilience of a particularly fast-growing teleost prey species (red cod, Pseudophycis bachus)

2013 ◽  
Vol 64 (2) ◽  
pp. 130
Author(s):  
Jodie Kemp ◽  
Gregory P. Jenkins ◽  
Stephen E. Swearer
Keyword(s):  
Life History ◽  
Prey Species ◽  
First Year ◽  
Early Maturity ◽  
High Fecundity ◽  
Biomass Harvesting ◽  
Important Prey ◽  
Rapid Growth Rate ◽  
Poor Recruitment ◽  
Water Species

Understanding the life-history parameters that influence productivity is important in assessing the intrinsic resilience of a species to exploitation. The life-history characteristics of red cod, Pseudophycis bachus, were investigated to assess the intrinsic resilience of this important prey species to increased predation pressure by a range of high trophic-level predators. Red cod has a particularly short longevity; in Australian shelf waters it is uncommon to encounter individuals older than 2+ years. There are few shelf-water species that exhibit the rapid rate of growth that was observed where females and males attained ~300-mm total length in the first year. A particularly rapid growth rate, and a reproductive strategy characterised by early maturity and high fecundity, suggests that the species is relatively resilient. However, red cod is short lived, which exposes populations to large shifts in biomass. Harvesting of this species by predators, particularly during years of poor recruitment, may be significant in shaping the dynamics of red cod populations.

Culturable autotrophic ammonia-oxidizing bacteria population and nitrification potential in a sheep grazing intensity gradient in a grassland on the Loess Plateau of Northwest China

2011 ◽  
Vol 91 (6) ◽  
pp. 925-934 ◽  
Author(s):  
Tianzeng Liu ◽  
Zhibiao Nan ◽  
Fujiang Hou
Keyword(s):  
Loess Plateau ◽  
Soil Depth ◽  
Grazing Intensity ◽  
Northwest China ◽  
Ammonia Oxidizing Bacteria ◽  
Stocking Rate ◽  
The Loess Plateau ◽  
Soil Microbial ◽  
Nitrification Potential ◽  
Dry Soil

Liu, T., Nan, Z. and Hou, F. 2011. Culturable autotrophic ammonia-oxidizing bacteria population and nitrification potential in a sheep grazing intensity gradient in a grassland on the Loess Plateau of Northwest China. Can. J. Soil Sci. 91: 925–934. Grazing is known to enhance the activity of soil microbial communities in many types of grasslands; however, the potential impacts of rotational grazing activity on soil microbial functional groups remain poorly understood. We investigated the effects of 9 yr of rotational grazing by livestock on culturable autotrophic ammonia-oxidizing bacteria (AOB) population size, nitrification potential and soil properties in a semi-arid grassland of the Loess Plateau in Northwest China. Three stocking rate treatments of 2.7, 5.3 and 8.7 wether lambs ha−1were evaluated in geographically separated paddocks. Grazing increased nitrification potential and culturable AOB populations compared with ungrazed treatments. Ammonia-oxidizing bacteria populations increased from 155 bacteria g−1dry soil with 0 sheep ha−1to 16 218 bacteria g−1dry soil with 8.7 sheep ha−1. Grazing led to an increase in population of AOB at 0–10 cm soil depth, but had no effect on AOB at 10–20 cm soil depth. Nitrification potential increased from 1.21 mg NO3-N kg−1soil d−1in ungrazed treatments to 2.86 mg NO3-N kg−1soil d−1at the highest stocking rate. Soil ammonium and nitrate concentrations increased; however, total soil nitrogen and soil moisture content decreased with increased stocking rate for both sampling depths (0–10 cm and 10–20 cm). Soil organic matter was not affected by grazing treatments. Soil nitrification potential and the size of culturable AOB populations were dependent on grazing intensity, soil depth and season. This information is potentially important for the optimal selection of stocking rate for grazed ecosystems.

Effect of grazing intensity and cultivar on morphology, phenology, and nutritive value of subterranean clover II. Nutritive value during the growing season

2000 ◽  
Vol 51 (8) ◽  
pp. 1047 ◽  
Author(s):  
Y. J. Ru ◽  
J. A. Fortune
Keyword(s):  
Mineral Content ◽  
Nutritive Value ◽  
Grazing Intensity ◽  
Subterranean Clover ◽  
Growing Season ◽  
Maturity Group ◽  
Early Maturity ◽  
Pasture Quality ◽  
Heavy Grazing

With the decline in pasture quality in southern Australia, the development of management strategies to improve nutrient supply for grazing animals is essential and requires a clear understanding of the interaction between animals and plants. The impact of grazing intensity on the morphology of subterranean clover was previously examined. This paper reports the effect of grazing intensity on the nutritive value of subterranean clover, and the variation in quality of cultivars during the growing season. Grazing intensity influenced nutritive value and interacted with cultivar maturity. Heavy grazing depressed dry matter digestibility (DMD) by 5 percentage units in October for early maturity cultivars but increased DMD by 3 percentage units in September for mid maturity cultivars. The influence of grazing intensity on nitrogen content was small. Heavy grazing did not affect acid detergent fibre for the early maturity group, but depressed it for the mid maturity group throughout the season. Acid detergent lignin remained comparable for all cultivars during the season. Mineral content of subterranean clover showed variable response to grazing treatments. Nutritive value varied among cultivars within each maturity group. DMD ranged over 53–64%, 44–62%, and 45–53% for early, mid, and late maturity groups, respectively, at the end of the growing season. The cultivar rank in all nutritional parameters changed with the progress of the season. The large ranges in the decline rate of DMD within each maturity group during the last 8 weeks of growth gave an indication of the potential quality of the cultivars during late spring and early summer. Despite the variation in mineral content there were no cultivars in which the concentration of minerals was below the minimum requirements of sheep. These results indicate that there is a potential for the selection of high quality cultivars within a breeding program, and that indicative targets of grazing intensity need to be further developed with a focus on pasture quality.

Effect of food availability on reproduction and brood size in a freshwater brooding bivalve

2003 ◽  
Vol 81 (7) ◽  
pp. 1168-1173 ◽  
Author(s):  
Mark A Beekey ◽  
Ronald H Karlson
Keyword(s):  
Food Availability ◽  
Brood Size ◽  
Reproductive Strategies ◽  
Common Garden ◽  
Relative Importance ◽  
Common Garden Experiment ◽  
Freshwater Bivalve ◽  
Physical Constraints ◽  
Effect Of Food ◽  
Energetic Constraints

Brood size is often constrained by the amount of energy available to produce offspring. Yet, energetic constraints may not be as important if the physical capacity to brood offspring is limited. Investigating the relative importance of energetic and physical constraints on brood size is necessary to understand how reproductive strategies are molded by natural selection. We investigated how food availability affects brood size in Sphaerium striatinum, a freshwater bivalve. We reared juveniles to adulthood under three food levels in a common garden experiment. The number of reproductive attempts, brood size, and stage of offspring development were measured. Clams reared with the most food reproduced more often, produced more offspring per reproductive attempt, and contained larger broods than clams reared with less food. These data support the notion that food availability is an important factor in the production of offspring and overall brood size. However, the number of offspring surviving to later stages of development was not different among treatments. In fact, clams reared with the most food lost proportionately more offspring than clams reared with less food. We conclude that physical constraints are more important in determining overall brood size than energetic constraints in S. striatinum.

Herbage and animal production from native pastures and pastures oversown with Stylosanthes hamata. 1. Fertiliser and stocking rate effects

1993 ◽  
Vol 33 (5) ◽  
pp. 561 ◽  
Author(s):  
CJ Gardener ◽  
MR McCaskill ◽  
JG McIvor
Keyword(s):  
Animal Production ◽  
Stocking Rate ◽  
Heteropogon Contortus ◽  
Stylosanthes Hamata ◽  
Stylosanthes Humilis ◽  
Native Pasture ◽  
Utilisation Rate ◽  
Native Pastures ◽  
Fertiliser Application ◽  
Stocking Rates

Native pastures dominated by Heteropogon contortus (speargrass) were sown to Stylosanthes hanzata cv. Verano in 1972, and herbage production and steer growth rates were compared with those of native pastures from 1973 to 1985. The native pastures also contained naturalised Stylosanthes humilis, but its contribution to pasture yield diminished rapidly, after infection by Colletotrichum gloeospoirioides (anthracnose) in 1973. The experiment was a factorial design of 2 pasture types (native, native plus Verano) x 2 stocking rates (0.6, 1.2 steers/ha) x 2 superphosphate treatments (nil, 300 kg/ha.year) x 2 replicates. Fertiliser application decreased the proportion of legume but had no significant effect on herbage or animal production on this comparatively fertile site (extractable P, 18 mg/kg). Annual liveweight gains at the high and low stocking rates, respectively, on the native pasture averaged 100 and 120 kg/steer. Sowing to Verano did not affect herbage yields but increased annual liveweight gains by 28 and 36 kg/steer at low and high stocking rates. The high stocking rate of 1.2 steers/ha was sustainable for the first 9 years of the experiment, when above-average rainfall was received. However, in the following 3 below-average years, there was a shift to less-desirable species, and a decline in pasture productivity. Relative to the low stocking rate, herbage production on the native pasture in the final season was reduced by 60% and on the Verano pasture by 26%. The highest annual herbage utilisation rate that appeared sustainable in the long term was about 45%, which corresponded to a utilisation rate of 30% during the growing season (about November-May). When oversown with Verano, speargrass tended to decline in favour of annual grasses, weeds, and the introduced grass Urochloa mosanzhicensis, which had been sown on an adjacent experiment. Urochloa appeared to be a more suitable companion species than speargrass for Verano.

scholarly journals Simulating the impact of fertiliser strategies and prices on the economics of developing and managing the Cicerone Project farmlets under climatic uncertainty

2013 ◽  
Vol 53 (8) ◽  
pp. 806 ◽  
Author(s):  
Karl Behrendt ◽  
James M. Scott ◽  
Oscar Cacho ◽  
Randall Jones
Keyword(s):  
Soil Fertility ◽  
Stocking Rate ◽  
High Rainfall ◽  
Efficient Management ◽  
Fertiliser Application ◽  
The Cost ◽  
The Impact ◽  
Stocking Rates ◽  
Future Management

The application of fertilisers to pastures in the high rainfall regions of southern Australia has contributed to large increases in carrying capacity following the widespread adoption of the practice since the late 1940s. Recently, large shifts in the worldwide demand for fertiliser inputs have lead to large rises in the cost of fertiliser inputs. These increasing costs have significant potential ramifications on the future management of soil fertility and its interaction with the persistence and profitability of sown pastures, especially during periods of climatic uncertainty. A dynamic pasture resource development simulation model was used to investigate the implications of fertiliser rates and costs on the efficient management of soil fertility under climatic uncertainty. The framework also allowed the investigation of how the management of soil fertility interacts with the utilisation of pasture resources through different stocking rates. In the application of this method to the Cicerone Project farmlets case study, fertiliser input costs were found to influence the optimal combination of fertiliser inputs and stocking rate. Analyses of the dynamic interaction between fertiliser application and cost, stocking rate and the persistence of desirable species enabled the identification of the most risk-efficient strategies. The implications for grazing industries in the high rainfall regions of southern Australia are discussed.

White clover incorporation at high nitrogen application levels: results from a 3-year study

2020 ◽  
Vol 60 (1) ◽  
pp. 187 ◽  
Author(s):  
C. Guy ◽  
D. Hennessy ◽  
T. J. Gilliland ◽  
F. Coughlan ◽  
B. McClearn ◽  
...  
Keyword(s):  
White Clover ◽  
Production Systems ◽  
Stocking Rate ◽  
High Nitrogen ◽  
Negative Effects ◽  
Intensively Managed ◽  
Fertiliser Application ◽  
Grass Growth ◽  
Stocking Rates ◽  
Clover Content

Context High nitrogen (N)-fertiliser application levels and high stocking rates have been shown to optimise herbage dry-matter (DM) production in grass-only systems. Conversely, swards including white clover (Trifolium repens L.) are commonly suited to production systems at low N-fertiliser application levels (<150 kg N/ha) and low stocking rates (fewer than two livestock units (LU) per hectare). Despite this, the use of N fertiliser on grass–clover swards has generally increased during the past few decades, particularly in more intensively managed swards under dairy farming. Increasing inorganic N decreases sward white clover content in grass–clover swards, and increasing stocking rate on grass–clover swards can result in damage to white clover plants. However, under high N-application levels, a high stocking rate can also potentially minimise the negative effects of increased grass growth on sward white clover content. Aims The objective of the present study was to investigate the persistency of white clover in an intensive animal-grazing system, under a high N-fertiliser application level (250 kg N/ha) and at a high stocking rate (2.75 LU per hectare) over a 3-year period (2014–2016). Methods The study was a 2 × 2 factorial design, consisting of two perennial ryegrass ploidies (diploid, tetraploid) and two white clover treatments (grass-only, grass–clover). Four sward treatments (diploid-only, tetraploid-only, diploid + clover, tetraploid + clover) were evaluated over a full grazing season at a system scale. Sward measurements were taken at each grazing occasion for 3 years. Key results Over the 3 years, grass–clover swards produced an additional 1468 kg DM/ha when compared with grass-only swards. Sward white clover content decreased by 17% over the three study years. Conclusions This decrease in sward white clover content led to a decrease in contribution to cumulative herbage DM production. Implications Although the present study showed that white clover inclusion can increase herbage DM production at high N-fertiliser application levels, in association with high stocking rates, the initial extra herbage DM production on grass–clover swards decreased each year. Further studies should be undertaken to investigate whether the decline in white clover persistence observed is progressive over a longer time period.

An evaluation of grazing oats for grain and wool production in north-eastern Victoria

1978 ◽  
Vol 18 (91) ◽  
pp. 202 ◽  
Author(s):  
DJ Cannon ◽  
MJ Sharkey ◽  
PT Stewart
Keyword(s):  
Land Use ◽  
Grazing Intensity ◽  
Stocking Rate ◽  
Wool Production ◽  
North East ◽  
System 2 ◽  
Plot Area ◽  
The Mean ◽  
System 1 ◽  
Stocking Rates

Oat yields and wool production of Merino wethers were measured at five stocking rates in five systems of land use in each of two years, 1971 and 1972, in north-east Victoria. Nominal stocking rates were 6.8, 8.6, 10.5, 12.4 and 14.2 sheep ha-1. The production at each stocking rate was compared in the following systems: 1, all pasture; 2, and 3. pasture grazed year long with oats grazed in winter and oat stubbles in summer on 15 per cent (system 2) or 30 per cent of the plot area (system 3) ; 4. and 5. pasture grazed throughout with oat stubbles grazed in summer but crops not grazed during the growing season and crops comprised either 15 per cent (system 4) or 30 per cent of the plot area (system 5). In 1971 the rainfall of 540 mm was sufficient to produce a harvestable oat crop and to maintain sheep on all plots without supplements. The mean oat yield of 2.04 � 0.01 t ha-1 for system 3 far exceeded that of the more heavily grazed crops in system 2 (1.44-0.05) or of ungrazed crops in systems 4 and 5 (1.44i-0.07). Clean wool production per head from each system was compared in terms of an 'average' stocking rate S which accounted for variation in grazing intensity throughout the year inherent in systems 2, 3, 4, 5. In 1971 clean wool production kg-1 declined with increase in average stocking rate in all systems but the mean of the four dual land use systems did not differ from the all pasture system (1). 1972 was a drought year with only 330 mm of rain, oat crops failed to produce grain and were grazed from October. The wool production of sheep on systems 2 to 5 was greater than that of sheep at equivalent average stocking rates on the all pasture system. Growing oats for grazing and grain in association with wool production would appear to be more profitable than wool production alone. Light grazing of oats in winter may increase oat yield but more information is needed in relation to seasonal variation and oat variety.

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