scholarly journals Precise aerial fertiliser application on hill country

1999 ◽  
pp. 221-226
Author(s):  
A.G. Gillingham ◽  
J. Maber ◽  
J. Morton ◽  
M. Tuohy
Keyword(s):  
Application Rate ◽  
Economic Returns ◽  
Related Factors ◽  
Pasture Production ◽  
Economic Return ◽  
Soil P ◽  
Topographic Complexity ◽  
Hill Country ◽  
Olsen P ◽  
Fertiliser Application

The fertiliser requirements of hill country vary with soil type, slope and aspect-related factors which govern pasture production potential and species composition. In most situations, the topographic complexity is such that only very broad differentiation in land units can be made when aerially applying fertiliser. The traditional method of aerial topdressing is for superphosphate to be flown on at a common rate over large blocks of complex topography by fixed-wing aircraft. Advances in geographical positioning system (GPS) and aircraft technology now allow aircraft to fly accurately defined track spacing and so achieve optimum uniformity of fertiliser spread. The same technology could be used to vary fertiliser application rate along a flight path according to predetermined recommendations and through links to a farm geographic information system (GIS) map. This approach could also be used to apply different fertiliser types. In a desktop study the effects of differential, compared with uniform, fertiliser application policies, on animal productivity and economic returns were examined for three contrasting hill farm situations using a combination of trial results and the AgResearch PKS Lime Programme. Results showed that for a farm with a low soil P status (Olsen P =9), that stocking rate could be increased by 0.5 su/ha, and the economic return by 7.5%, by differential, rather than uniform fertiliser application. In a similar but higher soil P status farm (Olsen P = 15), the increase was 0.9 su/ ha and 10.1% respectively. In a summer-dry situation where nitrogen fertiliser could be substituted for some P fertiliser, a differential policy designed to optimise production gave a 2.1 su/ha and 43% net margin increase, compared with the uniform application of a typical rate of maintenance P fertiliser only. The results from the desktop study are discussed in relation to the practical aspects of developing differential fertiliser application methods. This will relate to extra fertiliser application cost, and the definition of practical sized land units and fertiliser forms, which will all have some effect on the net economics of a differential application policy. Despite these unknowns, the technology would appear to offer real gains to the hill country farmer. Keywords: economic return, fertiliser application, GIS, GPS, hill country, phosphate

Long term effects of withholding phosphate application on North Island hill country: Whatawhata Research Centre

1990 ◽  
pp. 11-16
Author(s):  
A. G.Gillingham S. Richardson ◽  
I.L. Power ◽  
J. Riley
Keyword(s):  
Large Scale ◽  
Soil Depth ◽  
Residual Effects ◽  
Research Centre ◽  
Total Production ◽  
Long Term Effects ◽  
Pasture Production ◽  
Hill Country ◽  
Olsen P ◽  
Fertiliser Application

From June 1984 to May 1988 a large-scale grazing trial at Whatawhata Research Centre evaluated the effects of a halt to previous superphosphate fertiliser application on hill country production. Over the 4-years pasture production, pasture species composition, stock grazing days or Olsen P soil fertility status were little affected as a result of halting topdressing. Pasture production declined most on 'easy' ( lo-20° slope) slopes after a halt to fertiliser application. The decline was greatest (lo- 13 %) where previous rates of fertiliser had been high. Total production on 'steep' (30~40° slope) slopes did not decline significantly. However, at soil test (Olsen P) levels of less than 10 the pasture moss and dead matter content increased, indicating a deterioration in pasture quality. Legume content did not decline. Within the range of normal topdressing rates to hill country (O-30 kg P/ha/yr) Olsen P tests did not reflect topdressing differences or any effects of a halt to fertiliser application. At higher topdressing rates (50-100 kg Plhalyr) the effect of continued or discontinued topdressing was reflected predominantly in the O-3 cm soil depth. A halt to previous topdressing significantly reduced available grazing over the final 3 years. This decline reflected the decline in measured pasture production. Keywords Phosphate, fertiliser, hill country, residual effects

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

scholarly journals Estimation of the P Fertilizer Demand of China Using the LePA Model

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenjia Yu ◽  
Haigang Li ◽  
Peteh Mehdi Nkebiwe ◽  
Guohua Li ◽  
Torsten Müller ◽  
...  
Keyword(s):  
Crop Yields ◽  
Removal Rate ◽  
Application Rate ◽  
Assessment Model ◽  
Soil P ◽  
Olsen P ◽  
P Fertilizer ◽  
P Application ◽  
Fertilizer Demand ◽  
P Removal

Modern phosphate (P) fertilizers are sourced from P rock reserves, a finite and dwindling resource. Globally, China is the largest producer and consumer of P fertilizer and will deplete its domestic reserves within 80 years. It is necessary to avoid excess P input in agriculture through estimating P demand. We used the legacy P assessment model (LePA) to estimate P demand based on soil P management at the county, regional, and country scales according to six P application rate scenarios: (1) rate in 2012 maintained; (2) current rate maintained in low-P counties and P input stopped in high-P counties until critical Olsen-P level (CP) is reached, after which rate equals P-removal; (3) rate decreased to 1–1.5 kg ha−1 year−1 in low-P counties after CP is reached and in high-P counties; (4) rate in each county decreased to 1–8 kg ha−1 year−1 after soil Olsen-P reached CP in low P counties; (5) rate in each county was kept at P-removal rate after reduction; (6) P input was kept at the rate lower than P-offtake rate after reduction. The results showed that the total P fertilizer demand of China was 750 MT P2O5, 54% of P fertilizer can be saved from 2013 to 2080 in China, and soil Olsen-P of all counties can satisfy the demand for high crop yields. The greatest potential to decrease P input was in Yangtze Plain and South China, which reached 60%. Our results provide a firm basis to analyze the depletion of P reserves in other countries.

scholarly journals Conversion of forestry land back to productive pasture

2004 ◽  
pp. 157-162 ◽  
Author(s):  
M.F. Hawke
Keyword(s):  
Soil Ph ◽  
Soil Fauna ◽  
Commodity Prices ◽  
Pine Forests ◽  
Forest Site ◽  
Pasture Production ◽  
Trial Site ◽  
Soil P ◽  
Olsen P ◽  
Clover Root

Large areas of pine forests have been logged and the land sold to farmers for converting to pasture in the South Waikato district. This land use change is expected to continue, given the present commodity prices. A trial was conducted on an ex-forest site at Rotorua to assess the feasibility of converting land from forestry to pastoral agriculture. The establishment of pasture (ryegrass and white clover) on an ex-forest site was successful and results after 4 years indicated there were no major problems with the conversion. An application of 4 t lime/ha lifted soil pH levels into the optimum range of 5.8-6.0 and an annual maintenance dressing of 40 kg phosphorus (P) /ha has more than maintained optimum Olsen P levels of 35-45 μg/ml for pasture growth. It is expected however that commercial sites where post-forest soil P levels were lower than on the Rotorua trial site, would require higher capital P fertiliser input. Soil fauna surveys indicated a recolonisation of some soil macro fauna e.g. earthworms, grass grubs and clover root weevil. Recommendations for converting pines to pasture include removal of stumps and forest debris (where practical), vigorous weed control and the application of nutrients such as phosphate that promote pasture production. Keywords: forestry, soil Olsen phosphorus, soil pH, pasture, Pinus radiata

scholarly journals Modelling hill country pasture production: a decision tree approach

2004 ◽  
pp. 195-201
Author(s):  
B.S. Zhang ◽  
I. Valentine ◽  
P.D. Kemp
Keyword(s):  
Decision Tree ◽  
Summer Drought ◽  
Pasture Management ◽  
Pasture Production ◽  
Hill Country ◽  
The North ◽  
Hill Slope ◽  
Tree Models ◽  
Fertiliser Application ◽  
Autumn And Winter

Decision tree models were applied to predict annual and seasonal pasture production and investigate the interactions between pasture production and environmental and management factors in the North Island hill country. The results showed that spring rainfall was the most important factor influencing annual pasture production, while hill slope was the most important factor influencing spring and winter production. Summer and autumn rainfall were the most important factors influencing summer and autumn production respectively. The decision tree models for annual, spring, summer, autumn and winter pasture production correctly predicted 82%, 71%, 90%, 88% and 90 % of cases in the model validation. By integrating with a geographic information system (GIS), the outputs of these decision tree models can be used as a tool for pasture management in assessing the impacts of alternative phosphorus fertiliser application strategies, or potential climate change, such as summer drought on hill pasture production. This can assist farmers in making decisions such as setting stocking rate and assessing feed supply. Keywords: data mining, decision tree, GIS, hill slope, rainfall

Resident hill country pasture production in response to temperature and soil moisture over 20 years in Central Hawke’s Bay

2021 ◽  
Vol 17 ◽  
Author(s):  
Annamaria Mills ◽  
Beverley Thomson ◽  
Paul Muir ◽  
Noel Smith ◽  
Derrick Moot
Keyword(s):  
Growth Rates ◽  
Climate Data ◽  
Pasture Production ◽  
Hill Country ◽  
Use Efficiency ◽  
Climate Station ◽  
Fertiliser Application ◽  
Highly Correlated ◽  
Response To Temperature ◽  
Water Holding

The production of resident pastures on rolling hill country was measured in three paddocks over 20 years at Poukawa in Central Hawke’s Bay. The pastures had been routinely fertilised with 250 kg/ha/yr of superphosphate but no pasture renovation, nor nitrogen fertiliser application, occurred during the measurement period. Total annual dry matter (DM) yield ranged from 4.5 to 12.8 t/ha/yr, which shows the level of variability to be expected in this summer-dry environment. The greatest proportion (60-90%) of growth occurred in winter/spring with consistent mean growth rates of 50-62 kg DM/ha/d in September and October. These rates were calculated to be 5.49±0.55 kg DM/ha/°Cd when spring moisture was non-limiting. The pastures had a mean water use efficiency of 16.9±0.34 kg DM/ha/mm of water available (R2 = 0.93). The amount of water available was calculated from a soil water budget based on a plant available water holding capacity of 124 mm (0-1.0 m depth). The results provide coefficients that can be combined with readily available climate data to predict pasture growth rates for feed budgeting purposes. Rainfall data collected on-site was highly correlated (r=0.94) with that predicted from the NIWA virtual climate station network.

Changes in soil phosphorus availability and potential phosphorus loss following cessation of phosphorus fertiliser inputs

Soil Research ◽  
2013 ◽  
Vol 51 (5) ◽  
pp. 427 ◽  
Author(s):  
R. J. Dodd ◽  
R. W. McDowell ◽  
L. M. Condron
Keyword(s):  
Agricultural Soils ◽  
Soil Phosphorus ◽  
Pasture Production ◽  
Soil P ◽  
Olsen P ◽  
P Loss ◽  
P Concentration ◽  
Rate Of Decline ◽  
P Retention

Long-term application of phosphorus (P) fertilisers to agricultural soils can lead to in the accumulation of P in soil. Determining the rate of decline in soil P following the cessation of P fertiliser inputs is critical to evaluating the potential for reducing P loss to surface waters. The aim of this study was to use isotope exchange kinetics to investigate the rate of decline in soil P pools and the distribution of P within these pools in grazed grassland soils following a halt to P fertiliser application. Soils were sourced from three long-term grassland trials in New Zealand, two of which were managed as sheep-grazed pasture and one where the grass was regularly cut and removed. There was no significant change in total soil P over the duration of each trial between any of the treatments, although there was a significant decrease in total inorganic P on two of the sites accompanied by an increase in the organic P pool, suggesting that over time P was becoming occluded within organic matter, reducing the plant availability. An equation was generated using the soil-P concentration exchangeable within 1 min (E1 min) and P retention of the soil to predict the time it would take for the water-extractable P (WEP) concentration to decline to a target value protective of water quality. This was compared with a similar equation generated in the previous study, which used the initial Olsen-P concentration and P retention as a predictor. The use of E1 min in place of Olsen-P did not greatly improve the fit of the model, and we suggest that the use of Olsen-P is sufficient to predict the rate of decline in WEP. Conversely, pasture production data, available for one of the trial sites, suggest that E1 min may be a better predictor of dry matter yield than Olsen-P.

scholarly journals SOIL FERTILITY AND HILL COUNTRY PRODUCTION

1982 ◽  
pp. 153-160 ◽  
Author(s):  
M.G. Lambert ◽  
P.C. Luscombe ◽  
D.A. Clark
Keyword(s):  
Summer Rainfall ◽  
Research Area ◽  
Grazing Management ◽  
Low Fertility ◽  
N Availability ◽  
Stocking Rate ◽  
Pasture Production ◽  
Hill Country ◽  
Olsen P ◽  
Legume Growth

Soil, pasture and animal responses to 2 levels of superphosphate were measured within a farmlet trial, at Ballantrae hill country research area, near Woodville, during 1975-80. Soil and pasture measurements were also made for 3 years before the trial started. Pastures, which were dominated by low-fertility-tolerant grasses (LFTC;), moss and flatweeds, were oversown with 4 legumes before the trial started. Soil Olsen P level was 5 under untopdressed pasture in 1973, and 9 in 1975 after application of 500 kg/ ha superphosphate. Superphosphate rates were 120 (on low fertiliser areas q LF) and 640 (on high fertiliser areas = HF) kg/ ha/ yr average during 1975/80. Annual pasture production (adjusted for variable summer rainfall) was 7.1 t DM/ ha from untopdressed pasture and 8.1 t following 500 kg superphosphate/ ha in 1973-74. LF production rose to 8.5, and HF to 12.0, in 1980. Legume contribution rose from 5% in untopdressed pasture to 18% and 23% in LF and HF respectively in 1975/76. By 1979/80 legume contribution had steadily declined to 10% on both treatments, probably due to a measured increase in soil N availability and increased competitiveness of associated grasses. Ryegrass content rose at both fertiliser levels, while LFTG content fell; these trends were greatest under HF. Winter stocking rate was increased from 6 to 10.9 and 14.9 su/ha on LF and HF-respectively. Per animal performance did not decrease. A range of techniques which could increase efficiency of superphosphate use in hill country is discussed. These techniques include: selective application to responsive pastures; spring application; grazing management to encourage legume growth.

The role of differential fertiliser application in sustainable management of hill pastures

2003 ◽  
pp. 253-257
Author(s):  
A.G. Gillingham ◽  
J.D. Morton ◽  
M.H. Gray
Keyword(s):  
Management Plan ◽  
Economic Benefits ◽  
Environmental Benefits ◽  
High Rate ◽  
Yield Potential ◽  
High Yield ◽  
Pasture Production ◽  
Hill Country ◽  
Wide Range ◽  
Fertiliser Application

New targets for increased productivity from the sheep and beef industry are about 4% annually, at a time of ever heightening environmental awareness. A major part of this will occur by applying current technology to increase the productivity from the presently lowerthan- average farms. However leading farmers will also have to increase efficiency or productivity if they are to remain economically viable. One prospect is to examine the natural variability in hill pastures and determine if this can be more appropriately managed to improve economic returns. Hill farms have soil and topographic var iability, which can result in a wide range in pasture production. Yet a uniform rate of fertiliser is usually applied to such land. This results in under prescription of fertiliser for high yield potential zones, and similarly over prescription for low yielding zones. The conversion of easier hill land to dairying has shown how pasture productivity can be improved by applying higher rates of fertiliser and utilising the extra pasture efficiently. This approach could be applied within parts of hill farms. The main fertiliser used on hill farms is superphosphate which supplies phosphorus (P) and sulphur (S) for legume growth. This assumes that there is enough clover present to make it worthwhile. However most hill pastures, especially on steep slopes, are low in clover and as a result most are predominantly nitrogen (N) deficient for a large part of the year. The pasture responses to P and S are therefore limited by low soil N levels and N fertilisers give a better economic return. The application of a high rate of N fertiliser to hill country could more than double pasture production. The technology is almost ready to allow accurate, differential application of fertiliser to hill farms from fixed wing aircraft. This should further improve economic benefits. A differential fertiliser management plan has environmental benefits through improved soil stability and associated water quality from hill catchments. Keywords: differential fertiliser application, hill country, hill country variability

Effect of Different Phosphorus Fertilization Treatments on the Phosphorus Transference in an Aquatic Brown Paddy Soil

2010 ◽  
Vol 113-116 ◽  
pp. 155-160
Author(s):  
Quan Lai Zhou ◽  
Mu Qiu Zhao ◽  
Cai Yan Lu ◽  
Yi Shi ◽  
Xin Chen
Keyword(s):  
Paddy Soil ◽  
Threshold Value ◽  
Application Rate ◽  
Phosphorus Fertilization ◽  
Soil P ◽  
Olsen P ◽  
Fertilizer Application Rate ◽  
P Fertilizer ◽  
P Application ◽  
Phosphorus Application

This study investigated the effects of different rates of phosphorus application on vertical transference of P. An aquatic brown paddy soil was filled in organic glass columns using for the leaching experiments. The results indicated that significant vertical transference was found using change of Olsen-P and CaCl2-P. The transference distance was no more than 10cm when P application rate between 200 and 800 kg P ha-1, and was more than 10cm as P application rate above 800 kg P ha-1. We obtained the threshold value of Olsen-P was 53.7 mg kg-1 by split-line model, and calculated that the threshold value of P fertilizer application rate was 382.1 kg P ha-1 by relationship of soil Olsen-P concentration and P application rate. The soil P transference increased, if P application rate was above 382.1 kg P ha-1. It would be helpful for controlling the P fertilizer amount by field to decrease P loss.

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