Superphosphate maintains soil fertility and beef production on grazed white clover pastures in the subtropics. 2. Liveweight responses of beef cattle

1993 ◽  
Vol 33 (4) ◽  
pp. 435 ◽  
Author(s):  
PT Mears ◽  
BR Cullis
Keyword(s):  
White Clover ◽  
Linear Response ◽  
Exponential Model ◽  
Response Model ◽  
Quadratic Trend ◽  
Stocking Rate ◽  
Soil P ◽  
Stocking Rates ◽  
Extractable Soil

Growth of cattle was measured between 1974-75 and 1980-81 on a white clover (Trifolium repens) and carpet grass (Axonopus affinis) pasture receiving superphosphate applied at 0, 12, 24, and48 kg P/ha annually. Hereford weaner steers grazed the pastures at 1.67, 2.5, and 3.3 steers/ha. Linear responses to superphosphate and stocking rate were significant (P<0.001). The model estimating steer liveweight response to superphosphate comprised a long-term quadratic trend with seasonal variations. The liveweight response to superphosphate application was greatest in liveweight response to superphosphate applied at12 kg P/ha increased from 6.1 kg/steer.45 days in year 1 to 10.6 kg/steer.45 days in year 7. Average liveweight responses to 48 kg P/ha also increased from 34.0 kg/steer.45 days in year 1 to 78 kg/steer.45 days in year 7. Annual liveweight gain of steers at the low stocking rate (1.67/ha) without superphosphate declined from 165 kg/steer in year 1 to 38 kg/steer in year 7, while 24 kg P/ha maintained liveweight gain at 120-220 kg/steer. Annual liveweight gain was negatively related to stocking rate, averaging -31.3 kg/steer for each increment in stocking rate. Calculated stocking rates giving maximum liveweight production (122-469 kg/ha) varied between 2.2 and 3.6 steers/ha. Annual liveweight gain of steers was related to bicarbonate-extractable soil P using the exponential model, which accounted for 19% spring and least in autumn each year. Seasonal of the variation.It was concluded that maintenance dressings of superphosphate would be required when available soil P levels fell below 30 mg/kg, in order to maintain liveweight gains on white clover-Axonopus pastures. The linear response model will assist producers to decide on rates of superphosphate.

Superphosphate maintains soil fertility and beef production on grazed white clover pastures in the subtropics. 1. Residual soil phosphorus, sulfur, and nitrogen, and pasture growth responses

1993 ◽  
Vol 33 (4) ◽  
pp. 425 ◽  
Author(s):  
PT Mears ◽  
EJ Havilah ◽  
GH Price ◽  
RE Darnell ◽  
DJ McLennan ◽  
...  
Keyword(s):  
Soil Fertility ◽  
White Clover ◽  
Residual Soil ◽  
Residual Value ◽  
Stocking Rate ◽  
Growth Responses ◽  
Pasture Production ◽  
Soil P ◽  
Stocking Rates ◽  
Over Time

Phosphorus (P) as superphosphate was applied at 0, 12, 24, and 48 kg P/ha each year from 1972 to 1980 to an established white clover (Trifolium repens) and carpet grass (Axonopus affinis) pasture, to measure long-term changes in soil fertility and pasture production under grazing on a duplex soil in a coastal, subtropical environment. Hereford weaner steers grazed the pasture at 2 stocking rates (1.67 and 2.5 steers/ha) from 1972 to 1974, and at 3 stocking rates (1.67, 2.50, and 3.3 steers/ha) for 7 years to 1981. The effects of P and stocking rate during 1972-76 on pasture and animal production were small and variable, so the study was extended to 1980-81 to measure longer term P and stocking rate effects on soil fertility. Available soil P (bicarbonate-extracted) and sulfur (S, phosphate-extracted) responded (P<0.05) linearly over time to rates of maintenance superphosphate. For soil P, this effect increased with time and showed seasonal fluctuations, which were described by a model with linear and curvilinear functions. After 9 years, average soil P levels at the 4 rates of applied superphosphate changed from 32 to 12, 24, 45, and 91 mg P/kg soil, respectively. A residual value function (RVF) was used to predict the residual value of applied phosphorus over time, which fitted the observed values of available soil P for each fertiliser treatment (R2 = 0.99). The soil S response to superphosphate remained constant over time. Mean values at the 4 rates of applied superphosphate were 8, 11, 15, and 25 mg/kg. Over the 9 years, total soil nitrogen increased (P<0.01) linearly from 0.134 to 0.179% and pH decreased (P<0.05) slightly from 5.7 to 5.2, but neither was significantly affected by superphosphate application. Total pasture and clover growth measured in cages responded linearly to superphosphate, with maximum (P<0.05) response occurring in spring each year from 1972-73 to 1976-77. It was concluded that on this duplex soil with 32 mg/kg of bicarbonate-extractable P, omitting superphosphate reduced soil P after 12 months and pasture growth within 18 months. Annual applications of superphosphate from 125 to 250 kg/ha (12-24 kg P/ha) maintained bicarbonate-extractable soil P in the range 24-45 mg/kg and improved growth and seed reserves of white clover in this environment.

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.

Effects of rainfall, moisture stress, and stocking rate on the persistence of white clover over 30 years

1995 ◽  
Vol 35 (7) ◽  
pp. 1039 ◽  
Author(s):  
KJ Hutchinson ◽  
KL King ◽  
DR Wilkinson
Keyword(s):  
Soil Water ◽  
White Clover ◽  
Warm Season ◽  
Late Summer ◽  
Ground Level ◽  
Moisture Stress ◽  
Smoothing Splines ◽  
Water Model ◽  
Stocking Rate

The effects of spring rainfall, critical levels of summer moisture stress, and sheep stocking rates on the persistence of white clover (Trifolium repens cv. Huia) have been evaluated in a 30-year experiment (1964-93) based on sown, well-fertilised pasture. Plant species presence was measured each year as basal cover using a vertical 10-pin frame. Hits at ground level from 800 points/plot were recorded in late September on duplicate plots, which were set-stocked at 3 rates (10, 20 reduced to 15, 30 reduced to 20 d.s.e./ha). A soil-water model based on rainfall and tank evaporation was calibrated against on-site soil water measurements (0-260 mm) and used to predict soil water (mm) for weekly time steps over 30 years. Smoothing of long-term rainfall data (SYSTAT, Lowess) showed an overall decline in warm-season rainfall (October-March), which was punctuated by above-average (1969-74) and average runs of years (1983-90). Flexible smoothing splines (SAS) were used to indicate patterns of yearly white clover presence. For all stocking treatments, there were significant declines in the presence of white clover over 3 decades. At the highest stocking rate, the recovery of white clover following the 1965 drought was poor. Late summer (January-March) moisture stress, defined as the number of weeks when soil water (0-260 mm) was <15 mm, was critical in determining white clover presence in the following spring (September). Rainfall received from October to December generally had a positive effect. These climate-based relationships reinforce the importance of stolon growth and survival as a regenerative strategy for white clover. However, over the 30 years, the species showed decreasing resilience post drought, which suggests a long-term failure of seed-based regeneration. Annual rates of soil nitrogen build-up ranged from 29 to 54 kg N/ha.year and were poorly related to white clover presence in the stocking treatments. Governing mechanisms, based on interactions between seasonal moisture stress, sheep stocking rate, interspecific plant competition, and seed pool dynamics, are proposed to explain the nature of long-term decline in white clover presence in well-fertilised, sown pastures in the Northern Tablelands of New South Wales.

scholarly journals Possible biases in scaling-based estimates of glacier change: a case study in the Himalaya

2020 ◽  
Vol 14 (9) ◽  
pp. 3235-3247
Author(s):  
Argha Banerjee ◽  
Disha Patil ◽  
Ajinkya Jadhav
Keyword(s):  
Response Time ◽  
Climate Sensitivity ◽  
Linear Response ◽  
Model Simulation ◽  
Change Scenario ◽  
Response Model ◽  
Future Evolution ◽  
Scaling Model ◽  
Mountain Glaciers

Abstract. Approximate glacier models are routinely used to compute the future evolution of mountain glaciers under any given climate-change scenario. A majority of these models are based on statistical scaling relations between glacier volume, area, and/or length. In this paper, long-term predictions from scaling-based models are compared with those from a two-dimensional shallow-ice approximation (SIA) model. We derive expressions for climate sensitivity and response time of glaciers assuming a time-independent volume–area scaling. These expressions are validated using a scaling-model simulation of the response of 703 synthetic glaciers from the central Himalaya to a step change in climate. The same experiment repeated with the SIA model yields about 2 times larger climate sensitivity and response time than those predicted by the scaling model. In addition, the SIA model obtains area response time that is about 1.5 times larger than the corresponding volume response time, whereas scaling models implicitly assume the two response times to be equal to each other. These results indicate the possibility of a low bias in the scaling model estimates of the long-term loss of glacier area and volume. The SIA model outputs are used to obtain parameterisations, climate sensitivity, and response time of glaciers as functions of ablation rate near the terminus, mass-balance gradient, and mean thickness. Using a linear-response model based on these parameterisations, we find that the linear-response model outperforms the scaling model in reproducing the glacier response simulated by the SIA model. This linear-response model may be useful for predicting the evolution of mountain glaciers on a global scale.

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 (&lt;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.

Phosphorus fertilizer for nitrogen fertilized dairy pastures. 1. Long term effects on pasture, diet and soil

1997 ◽  
Vol 129 (2) ◽  
pp. 205-217 ◽  
Author(s):  
T. M. DAVISON ◽  
W. N. ORR ◽  
B. A. SILVER ◽  
R. G. WALKER ◽  
F. DUNCALFE
Keyword(s):  
N Fertilizer ◽  
Panicum Maximum ◽  
Phosphorus Fertilizer ◽  
Long Term Effects ◽  
Single Superphosphate ◽  
Soil P ◽  
P Fertilizer ◽  
Autumn And Winter ◽  
Extractable Soil

The phosphorus fertilizer requirements and long term productivity of nitrogen-fertilized Gatton panic (Panicum maximum cv. Gatton) pastures, grazed by lactating dairy cows, were evaluated over 7 years. Cows grazed at 2·6 cows/ha on pastures that received annually 100 or 300 kg N/ha at each of 0, 22·5 or 45 kg P/ha. Phosphorus treatments were applied as single superphosphate, balanced for calcium by applications of gypsum.The soil had an initial available soil phosphorus content of 40 mg/kg (bicarbonate extraction). At zero P fertilizer (0P), extractable soil P declined at the rate of 1·9 mg/kg each year; at 22·5P it was maintained close to the original level while at 45P it increased at 6·6 mg/kg each year. Increased P fertilizer caused significant (P<0·01) increases in plant P concentration from year 2 onwards. In years 6 and 7 there was significantly less green pasture and leaf on offer in 300N pastures at 0P than with 22·5P and 45P. There was no influence of rate of P fertilizer at 100N on pasture quantity on offer in any year. There were clear trends at 100N of decreasing total pasture and green dry matter (DM) on offer over the 7 years, but not at 300N.Cows at 300N consumed more leaf in the diet in autumn and winter than at 100N. Leaf was 55–60% of the diet in summer and autumn, but decreased to 21% (100N) and 37% (300N) in winter. Dead material in the diet was always higher at 100N. Pasture leaf percentage and leaf yield were the best individual predictors of leaf percentage in the diet. Diet P selected from pasture was reduced by the higher rate of N fertilizer in each season. Estimated P concentrations of the diet selected from pasture for summer, autumn and winter averaged 0·30, 0·38 and 0·28% DM for 100N and 0·19, 0·24 and 0·18% DM for 300N treatments, respectively.The response to P fertilizer was dependent on the rate of N fertilizer applied. The critical bicarbonate extractable soil P level for this soil type, below which pasture responses occurred, was 30 mg/kg at 300N. The critical level at 100N was not reached, but was <23 mg/kg P.

Stocking rate trials in Ankole, Uganda: II. Botanical analysis and oesophageal fistula sampling of pastures grazed at different stocking rates

1974 ◽  
Vol 82 (3) ◽  
pp. 507-516
Author(s):  
G. N. Harrington ◽  
D. Pratchett
Keyword(s):  
Growth Rates ◽  
Dry Matter ◽  
Stocking Rate ◽  
Normal Pattern ◽  
Brachiaria Decumbens ◽  
Themeda Triandra ◽  
Continuous Grazing ◽  
Stocking Rates ◽  
Grazing Pressures

SUMMARYBotanical analyses of trials grazed at 3·6, 2·4, 1·2, 0·8 and 0·6 ha/300 kg animal for 4 years are detailed. The two heaviest grazing pressures encouraged Brachiaria decumbens, a high quality grass, at the expense of Themeda triandra and Hyparrhenia filipendula. Rotational grazing allowed the weed grass Cymbopogon afronardus to regenerate after clearing more rapidly than did continuous grazing.Bullocks with oesophageal fistulas sampled pastures grazed at 2·4, 1·2 and 0·6 ha/animal at 4-weekly intervals for 12 months. The 0·6 ha/animal treatment was repeated on pasture cleared of the weed grass Cymbopogon afronardus. Cattle growth rates, both long term and at the time of sampling, were recorded.Cattle growth rates were greatest at 2·4 ha/animal but fistula sampling demonstrated that the diet was significantly lower in CP and higher in CF than the more heavily stocked treatments, which is contrary to the normal pattern. It is concluded that the differences in cattle growth rates at the different stocking rates were due to differences in dry-matter intake rather than the recorded differences in diet quality. The higher CP in the diet at the heavier stocking rates is ascribed to the increase of B. decumbens in the diet.An unexplained ceiling to cattle growth rates of ca. 0·5 kg/day, and a calculated drymatter intake of < 2·1% body weight/day, in the presence of unlimited forage of 10% CP and 55% apparent digestibility, makes it more economic to stock for maximum production per ha than per animal.

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.

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.

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