scholarly journals Dynamical systems modelling of the interactions of animal stocking density and soil fertility in grazed pasture

1997 ◽  
Vol 1 (1) ◽  
pp. 27-43 ◽  
Author(s):  
I. D. Wickham ◽  
G. C. Wake ◽  
S. J. R. Woodward ◽  
B. S. Thorrold
Keyword(s):  
Stocking Density ◽  
Optimal Combination ◽  
Mathematical Representation ◽  
Stocking Rate ◽  
Long Term Effects ◽  
Grazed Pasture ◽  
Application Rates ◽  
Systems Modelling ◽  
Fertiliser Application

To examine the long-term effects of fertiliser application on pasture growth under grazing, a mathematical representation of the pasture ecosystem is created and analysed mathematically. From this the nutrient application level needed to maintain a given stocking rate can be determined, along with its profitability. Feasible stocking levels and fertiliser application rates are investigated and the optimal combination found, along with the sensitivity of this combination. It is shown that profitability is relatively insensitive to fertiliser level compared with stocking rate.

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 Partial Nutrient Balances in Tropical Velvet Bean-Maize System in Zimbabwe

2017 ◽  
Vol 10 (1) ◽  
pp. 133
Author(s):  
Obert Jiri ◽  
Paramu L. Mafongoya
Keyword(s):  
Crop Production ◽  
Maize Yield ◽  
Nutrient Balances ◽  
Velvet Bean ◽  
Application Rates ◽  
Phosphate Fertiliser ◽  
Accurate Indication ◽  
Top Soil ◽  
Fertiliser Application

In a field experiment on legume-maize cropping sequence, the effect of nitrogen and phosphate fertiliser application on nutrient budgeting after a two year cropping cycle was studied. The results of this work showed that partial nutrient balances can give an indication about the sustainability of a system unless a full stock of all the nutrients is known. It is also clear from these results that there would unlikely be a carryover of N to the next season, probably due to leaching of N from the top soil. Positive partial P balances would, on the other hand, be of residual value. However, it should be noted that the positive partial P balances were only observed where maize yield was low. The long-term perspectives of a crop production system cannot be assessed solely on the basis of partial nutrient balances. The nutrient stock: balance ratio may be a better indicator of sustainability, giving a more accurate indication of how long farming can continue in the same way, given the available nutrients. These points towards taking a fresh look at the existing recommended application rates for maize crops.

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.

scholarly journals Long-Term Biosolids Applications to Overgrazed Rangelands Improve Soil Health

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1339
Author(s):  
Cassidy M. Buchanan ◽  
James A. Ippolito
Keyword(s):  
Soil Health ◽  
Organic Amendments ◽  
Application Rate ◽  
Land Application ◽  
Health Index ◽  
Long Term Effects ◽  
Health Indices ◽  
Application Rates ◽  
Biosolids Application

Overgrazed rangelands can lead to soil degradation, yet long-term land application of organic amendments (i.e., biosolids) may play a pivotal role in improving degraded rangelands in terms of soil health. However, the long-term effects on soil health properties in response to single or repeated, low to excessive biosolids applications, on semi-arid, overgrazed grasslands have not been quantified. Using the Soil Management Assessment Framework (SMAF), soil physical, biological, chemical, nutrient, and overall soil health indices between biosolids applications (0, 2.5, 5, 10, 21, or 30 Mg ha−1) and application time (single: 1991, repeated: 2002) were determined. Results showed no significant changes in soil physical and nutrient health indices. However, the chemical soil health index was greater when biosolids were applied at rates <30 Mg ha−1 and within the single compared to repeated applications. The biological soil health index was positively affected by increasing biosolids application rates, was overall greater in the repeated as compared to the single application, and was maximized at 30 Mg ha−1. The overall soil health index was maximized at rates <30 Mg ha−1. When all indices were combined, and considering past plant community findings at this site, overall soil health appeared optimized at a biosolids application rate of ~10 Mg ha−1. The use of soil health tools can help determine a targeted organic amendment application rate to overgrazed rangelands so the material provides maximum benefits to soils, plants, animals, and the environment.

Long term effects of withholding phosphate application on North Island hill country: Economics

1990 ◽  
pp. 29-33
Author(s):  
D.A. Clark ◽  
S.F. Ledgard ◽  
M.G. Lambert ◽  
M.B. O'Connor ◽  
A.G. Gillingham
Keyword(s):  
Cash Flows ◽  
Cost Ratio ◽  
Long Term Effects ◽  
Pasture Production ◽  
Soil P ◽  
Hill Country ◽  
Fertiliser Application ◽  
Positive Cash Flow ◽  
Sustainable Productivity

Results from fertiliser cessation experiments at Ballantrae, Te Kuiti and Whatawhata, on yellow-brown earths, were used to evaluate the fertiliser cessation compared to continued application on hill country breeding ewe systems. At Balhmtrae, on farmlets previously receiving 125 kg superphosphate/ha/yr, continued fertiliser application generated a positive cash flow after 8 years. On farmIets previously receiving rates of 200-375 kg superphosphate/ha/yr positive cash flows were generated by continued fertiliser application after 4, 5 and 6 years at Te Kuiti, Whatawhata and Ballantrae respectively. Fertiliser cessation is a sound strategy to survive periods of low product price:fertiIiser cost ratio. However, it will decrease sustainable productivity and hence farm resale value. Fertiliser recommendations cannot remain constant over time but must consider: animal enterprise, product and fertiliser price, soil P status, and level of pasture utilisation. Keywords fertiliser cessation, superphosphate, Olsen P, economics, hill country, pasture production

Long-term effects of sewage sludge application on sour cherry (Prunus cerasus L.)

2013 ◽  
Vol 61 (1-4) ◽  
pp. 51-56 ◽  
Author(s):  
Rafet Aslantas ◽  
Ilker Angin ◽  
Ahmet Orhan Kobaza
Keyword(s):  
Sewage Sludge ◽  
Vegetative Growth ◽  
Morphological Characteristics ◽  
Sour Cherry ◽  
Prunus Cerasus ◽  
Growth And Yield ◽  
Long Term Effects ◽  
Application Rates ◽  
Sludge Application

This study describes the long-term effects of different sewage sludge application rates on vegetative parameters, morphological characteristics, yield, and chemical properties of fruit and leaves of sour cherry (Prunus cerasusL.) cv. “Kütahya.” A three-year field experiment was set up in a completely randomized block design with six sewage sludge application rates (0.0, 2.5, 5.0, 7.5, 10.0 and 12.5 kg of dry matter per tree) and three replications. One-year-old Kütahya sour cherry trees grafted onPrunus mahalebrootstock were evaluated. In all application rates, sewage sludge altered vegetative growth parameters, morphological characteristics, and yield. The most effective application rate was 7.5 kg per tree, it increased cumulative yield more than twofold. The results obtained in this study demonstrate that application of sewage sludge to light-textured soil is an effective means for improvement of vegetative growth and yield, and that a single application of sewage sludge sustains its effects for at least 7 years.

scholarly journals Long-term effects of peatland black spruce regeneration treatments in northeastern Ontario

2005 ◽  
Vol 81 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Arthur Groot ◽  
Michael J Adams
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Stocking Density ◽  
Basal Area ◽  
Long Term Effects ◽  
Seeding Rate ◽  
Site Class ◽  
Advance Regeneration ◽  
Rate Effects

Studies of black spruce (Picea mariana (Mill.) BSP) broadcast seeding and of harvest methods for advance regeneration protection were remeasured 17 to 20 years after establishment on peatland sites in northeastern Ontario. The effects of seeding rate on black spruce stocking, density or basal area were apparent at two study locations 20 years after treatment, but high levels of advance regeneration masked seeding rate effects at two other study locations. The effects of different harvest methods on black spruce stocking, density and basal area, which were evident at earlier ages, were no longer statistically significant 17 to 19 years after treatment. Black spruce density increased moderately with time because of gradual recruitment of new seedlings. Density of black spruce stems taller than 1.3 m tall exceeded 4000 ha-1 for nearly all treatments, but these stems were spatially aggregated at the 4-m2 scale. The stand characteristics of these regenerated peatland stands are consistent with site class 2 stands in the Ontario normal yield tables. Key words: black spruce; Picea mariana; advance regeneration; direct seeding; regeneration; peatland; stand dynamics

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