Optimal management of fertiliser and stocking rate in temperate grazing systems

2010 ◽  
Vol 50 (1) ◽  
pp. 6 ◽  
Author(s):  
Karel Mokany ◽  
Andrew D. Moore ◽  
Phillip Graham ◽  
Richard J. Simpson
Keyword(s):  
Cash Flow ◽  
Application Rate ◽  
Optimal Management ◽  
Stocking Rate ◽  
Eastern Australia ◽  
Grazing Systems ◽  
Fertiliser Application ◽  
Gross Margins ◽  
Stocking Rates

Phosphorus (P) fertilisers are one of the key tools available for increasing pasture production and the profitability of grazing enterprises. However, recent rapid changes in fertiliser price have increased the importance of developing optimal management strategies for applying P fertiliser and setting stocking rates. We applied a novel combination of process-based grazing systems modelling and randomised cash flow analyses to examine how changes in fertiliser price affect optimal fertiliser application rates and stocking rates for sheep grazing systems in south-eastern Australia, simultaneously taking into account long-term economic viability and environmental sustainability. We used ‘GrassGro’, a grazing systems decision support tool, to simulate three sheep enterprise types (Merino wethers, Merino ewes, crossbred ewes) at two locations (Hamilton, Victoria; Bookham, New South Wales). Gross margins from each year simulated in GrassGro (1966–2007) were randomised 500 times and input to a cash flow analysis that identified the financially optimal stocking rate for a range of fertiliser applications and the financial risk frontiers (combinations of stocking rate and fertiliser input for which the enterprise becomes financially unviable). For all enterprises examined at both locations, the optimal combinations of stocking rate and fertiliser application rate did not vary markedly as fertiliser price changed. Regardless of enterprise type or location, the fertiliser application rate at which the highest gross margins were achieved provided the greatest range of stocking rates that were both financially viable and environmentally sustainable. Increases in fertiliser price reduced the combinations of stocking rate and fertiliser application rate that were viable in the long term, emphasising the importance of well informed grazing management decisions.

Economics of increasing the persistence of sown pastures: costs, stocking rate and cash flow

2000 ◽  
Vol 40 (2) ◽  
pp. 313 ◽  
Author(s):  
J. F. Scott ◽  
G. M. Lodge ◽  
L. H. McCormick
Keyword(s):  
Cash Flow ◽  
Cost Effective ◽  
Stocking Rate ◽  
Pasture Management ◽  
Spreadsheet Model ◽  
Reducing Costs ◽  
Substantial Decline ◽  
Ecologically Sustainable ◽  
Stocking Rates

Poor persistence of sown pastures, trends of low pasture resowing rates and a substantial decline in carrying capacity of non-crop areas bring into question the basis of the philosophy of pasture improvement by sowing pasture species. If graziers are to adopt grazing strategies or stocking rates that are more ecologically sustainable, then clearly they must also be cost-effective in either increasing income or reducing costs so that they are economically sustainable. This paper describes the use of an interactive spreadsheet model developed to assist graziers and their advisers with assessing the long-term profitability of pasture management and/or improvement (and therefore pasture persistence). The model provides a comparative cash flow for different levels of inputs (fertiliser, herbicides and feed supplements) over a 15-year period. Results clearly show that at the same stocking rate, different animal enterprises have markedly different profitabilities over a 15-year period. Further, for native, improved and sown pastures, the most profitable pastures are those that can sustain increased stocking rates for long periods of time, without the need for resowing.

Management of grazing systems

1989 ◽  
pp. 117-122 ◽  
Author(s):  
J. Hodgson
Keyword(s):  
Management Practices ◽  
Management Control ◽  
Grazing Management ◽  
Relative Importance ◽  
Stocking Rate ◽  
Pastoral Systems ◽  
Starting Point ◽  
Alternative Means ◽  
Grazing Systems ◽  
Stocking Rates

Recent assessments of the relative importance of stocking rate. stocking policy and grazing management on the output from pastoral systems are used as a starting point to argue the need for objective pasture assessments to aid control of livestock enterprises to meet production targets. Variations in stocking rates, stocking policy and other management practices all provide alternative means of control of pasture conditions which are the major determinants of pasture and animal performance. Understanding of the influence of pasture conditions on systems performance should provide a better basis for management control and for Communication between farmers, extension officers and researchers. Keywords: Stocking rate, pasture condition, pasture cover

Modelling phosphorus exports from rain-fed and irrigated pastures in southern Australia

Soil Research ◽  
2005 ◽  
Vol 43 (6) ◽  
pp. 745 ◽  
Author(s):  
D. Nash ◽  
L. Clemow ◽  
M. Hannah ◽  
K. Barlow ◽  
P. Gangaiya
Keyword(s):  
Component Model ◽  
Year Effect ◽  
Storm Flow ◽  
Additive Component ◽  
Eastern Australia ◽  
Grazing Systems ◽  
Fertiliser Application ◽  
Excessive Nutrients ◽  
Major Factors ◽  
Land Manager

Pasture-based grazing systems contribute to the excessive nutrients found in some streams in south-eastern Australia. This study investigated phosphorus (P) exported in runoff from a rain-fed dairy pasture (Darnum) and 4 bays of irrigated dairy pasture (MRF). Runoff was monitored for 7 years at Darnum and 2 years at the MRF to identify factors associated with the variation in total P (TP) concentrations between events. The flow-weighted mean annual P concentrations in runoff varied between 3.3 and 28.2 mg TP/L for Darnum and 6.2 and 31.5 mg TP/L for the MRF. The relationships between TP concentrations in runoff and days between fertiliser application and runoff, days between grazing and runoff, and total storm flow were examined using an additive component model that explained 61% and 70% of the variation in log-transformed TP for Darnum and the MRF, respectively. The interval between application of fertiliser and runoff and the effect of year were highly significant and explained most of the variation in TP. Grazing and fertiliser application were identified as the major factors that may affect TP concentrations that the land manager can control (preventable). The estimates of year effect (i.e. the component of TP not explained by the other variables and over which the land manager had no apparent means of control) ranged from 1.60 mg (s.e. 1.99) to 7.14 mg (s.e. 1.90) TP/L in non-drought years (>45 kL/ha runoff annually). The year effect averaged 5.7 and 6.9 mg TP/L for Darnum and the MRF, respectively. It is shown that an additive component model provides a useful structure for investigating similar, field-scale data.

Long-term cattle gain responses to stocking rate and grazing systems in northern mixed-grass prairie

2008 ◽  
Vol 117 (1) ◽  
pp. 60-69 ◽  
Author(s):  
Justin D. Derner ◽  
Richard H. Hart ◽  
Michael A. Smith ◽  
James W. Waggoner
Keyword(s):  
Stocking Rate ◽  
Mixed Grass Prairie ◽  
Mixed Grass ◽  
Grazing Systems

Long-Term Effects of Early Pruning and Thinning Treatments on Growth of Natural Longleaf Pine

1980 ◽  
Vol 4 (2) ◽  
pp. 77-79
Author(s):  
Robert C. Sparks ◽  
Norwin E. Linnartz ◽  
Harold E. Harris
Keyword(s):  
Longleaf Pine ◽  
Basal Area ◽  
Pinus Palustris ◽  
Diameter Growth ◽  
Stocking Rate ◽  
Long Term Effects ◽  
Natural Stand ◽  
Stocking Rates ◽  
Pruning Intensity

Abstract Pruning and thinning a young natural stand of longleaf pine (Pinus palustris Mill.) in southwest Louisiana had little influence on height. However, diameter growth was reduced substantially as pruning intensity or stocking rate increased up to 25-percent live crown and 200 stems per acre, respectively. Improved diameter growth at lower stocking rates was not sufficient to equal the total basal area increment of 200 trees per acre.

scholarly journals Impact of Climate Change on Livestock Returns and Rangeland Ecosystem Sustainability in the Southwest

2018 ◽  
Vol 47 (2) ◽  
pp. 336-356 ◽  
Author(s):  
Gregory L. Torell ◽  
Katherine D. Lee
Keyword(s):  
Climate Change ◽  
Current Method ◽  
Adaptive Methods ◽  
Livestock Grazing ◽  
Climate Projections ◽  
Stocking Rate ◽  
Forage Production ◽  
Temperature And Precipitation ◽  
Stocking Rates

Climate change will increase variability in temperature and precipitation on rangelands, impacting ecosystem services including livestock grazing. Facing uncertainty about future climate, managers must know if current practices will maintain rangeland sustainability. Herein, the future density of an invasive species, broom snakeweed, is estimated using a long-term ecological dataset and climate projections. We find that livestock stocking rates determined using a current method result in lower forage production, allowable stocking rate, and grazing value than an economically efficient stocking rate. Results indicate that using ecology and adaptive methods in management are critical to the sustainability of rangelands.

Productivity and intensive sheep stocking over a five-year period

1967 ◽  
Vol 69 (1) ◽  
pp. 47-69 ◽  
Author(s):  
C. R. W. Spedding ◽  
J. E. Betts ◽  
R. V. Large ◽  
I. A. N. Wilson ◽  
P. D. Penning
Keyword(s):  
Milk Yield ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Economic Implications ◽  
Production Processes ◽  
Percentage Weight ◽  
Grazing Systems ◽  
Sheep Production ◽  
Stocking Rates

During the last ten years or so, the management of sheep for intensive lamb production has been studied on a considerable scale, and a variety of grazing systems have been investigated (Dickson, 1959; Cooper, 1959; Spedding & Large, 1959; Boaz, 1959). It is still too soon to specify precisely the place that any of these systems should occupy in sheep-production processes, in relation to breed, lambing percentage, weight of lamb at slaughter, stocking rate, botanical composition of the pasture, size of ewe and level of her milk yield. Quite apart from these biological considerations, the full economic implications are by no means clear. What has emerged most clearly, however, is that much higher stocking rates can be tolerated than had generally been regarded as safe and that, at these stocking rates, productivity can be extremely high.

Modelling the risk of different joining times and lamb sale policies

2014 ◽  
Vol 54 (10) ◽  
pp. 1694 ◽  
Author(s):  
S. M. Robertson ◽  
A. F. Southwell ◽  
M. A. Friend
Keyword(s):  
Carrying Capacity ◽  
Simulation Modelling ◽  
Management Systems ◽  
Stocking Rate ◽  
Gross Margin ◽  
Feed Resources ◽  
Systems Simulation ◽  
Gross Margins ◽  
The Impact ◽  
Stocking Rates

Month of joining and lamb sale strategy influence both the quantity and so value of lamb produced, and the feed required, so are important management decisions contributing to the profitability of sheep systems. Simulation modelling was used to evaluate the impact on gross margins of three lamb sale strategies for different months of joining and varying stocking rates. A flock of purchased Merino ewes producing crossbred lambs in southern Australia was modelled between 1971 and 2011. April joining produced higher gross margins than November or January only if the number of ewes per hectare was increased to potential carrying capacity. At the optimum stocking rate for each month of joining, three sale policies – a flexible lamb sale policy (where lambs were sold depending on seasonal conditions); selling lambs in December; or selling at 45-kg liveweight, all produced a similar mean gross margin, but the feed resources required were least using the flexible strategy (April-joined mean 195 ± 253 s.d. kg/ha for flexible compared with 219 ± 270 kg/ha if selling December or 1085 ± 459 kg/ha if sold at 45 kg). Mean gross margin differed between sale strategies by up to AU$66/ha if the optimal stocking rate was not used. These results suggest that the most advantageous lamb sale strategy will vary with both month of joining and stocking rate used, and should be considered when optimising sheep management systems.

The effect of perennial ryegrass ploidy and white clover inclusion on milk production of dairy cows

2020 ◽  
Vol 60 (1) ◽  
pp. 143 ◽  
Author(s):  
Bríd McClearn ◽  
Trevor Gilliland ◽  
Clare Guy ◽  
Michael Dineen ◽  
Fergal Coughlan ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Milk Production ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Application Rate ◽  
Dairy Farmers ◽  
Increase Milk Production ◽  
Grazing Systems ◽  
Fertiliser Application ◽  
Grazing Dairy Cows

Grazed grass is considered the cheapest feed available for dairy cows in temperate regions, and to maximise profits, dairy farmers must utilise this high-quality feed where possible. Recent research has reported that including white clover (Trifolium repens L.) in grass swards can have a positive effect on milk production. The aim of the present study was to quantify the effect of tetraploid and diploid perennial ryegrass (Lolium perenne L.; PRG) swards sown with and without white clover on the milk production of grazing dairy cows. Four grazing treatments were used for the study; tetraploid-only PRG swards, diploid-only PRG swards, tetraploid PRG with white clover swards and diploid PRG with white clover swards. Thirty cows were assigned to each treatment and swards were rotationally grazed at a stocking rate of 2.75 cows/ha and a nitrogen-fertiliser application rate of 250 kg/ha annually. There was no significant effect of ploidy on milk production. Over the present 4-year study, cows grazing the PRG–white clover treatments had greater milk yields (+597 kg/cow.year) and milk-solid yield (+48 kg/cow.year) than cows grazing the PRG-only treatments. This significant increase in milk production suggests that the inclusion of white clover in grazing systems can be effectively used to increase milk production of grazing dairy cows.

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.

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