Aerial Topdressing Issues Around Product Flow Properties One Size - - PowerPoint PPT Presentation

Aerial Topdressing Issues Around Product Flow Properties

One Size Does Not Fill All NZCPA Miles Grafton, Rob Murray & Ian Yule

Email: M.Grafton@Massey.ac.nz

Problem Statement

• Materials Various
• Urea DAP Superphosphate Lime slurries and

liquids

• Many products’ properties change with time and

storage conditions

• Delivery Equipment Standard
• Hopper, box, multi-vane spreader or spray gear

Factors That Affect Bulk Solid Flow

• Moisture Content
• Humidity
• Temperature
• Pressure
• Fat (Not applicable to fertiliser)
• Particle Size Distribution
• Angle of Repose
• Bulk Density
• Angle of Internal Friction
• Cohesion
• Adhesion
• Compressibility (more than 20% tend not to be free flowing)

Mass Flow – Funnel Flow

Photographs provided by John Maber

Cohesive tapped Limes bridging in a beaker

Typical to all Limes tested

Bulk solids will vary in bulk density depending on their history

Bulk Density Comparisons

500 1,000 1,500 2,000 2,500 A B C D E F G H I Limes Kg/ cubic metre As ReceivedBulk Density Kg/m³ Tap Density Kg/m³ Loose Bulk Density Kg/m³

Jenike Shear Cell Some answers after some time

• Angle of internal friction angle of wall

friction

Some experimental work, some

geometry and some charts

Flow measurements LabView RFID tags & load cell

• Full Size Experiments will be undertaken

A Model Hopper to Compare Theoretical and Actual Hopper ½ Angles

• Shimadsu tensile tester to calibrate load

cell

Early days of NZ topdressing fertiliser in the top and out the bottom

Equipment has changed but the principle is the same

• Aircraft, Loaders, GPS, Materials

Structure of presentation

• Justification for modelling work
• Overall aim - VRAT
• Modelling particle ballistics
• Improving spreading techniques

Aerial topdressing technology

Where are we headed?

Variable rate of hill country: agronomic impact of using decision tree model

GPS Proof of Placement

GPS Well positioned aircraft & manual control of product release

Distribution pattern GA200c aircraft

100 200 300 400 500 600 700

• 13 -12 -11 -10
• 9
• 8
• 7
• 6
• 5
• 4
• 3
• 2
• 1

1 2 3 4 5 6 7 8 9 10 11 12 Distance from Centre (m) Application rate (kg ha-1) Actual Predicted

Comparison of the actual and predicted lateral distribution pattern for a thirty-tray transverse test for a Gippsland Aeronautics GA200C fixed wing aircraft with a six duct spreader. Data source: 2002 field report, aircraft flying conditions – altitude 25 m, superphosphate, ground speed 54 m s-1, wind velocity 0 m s-1, wind angle 0° from flight direction.

50 100 150 200 250

• 10
• 9
• 8
• 7
• 6
• 5
• 4
• 3
• 2
• 1

1 2 3 4 5 6 7 8 9 10 Lateral position (m) Deposition (kg ha-1) 0.5mm 1.9mm 3.7 mm 4.7 mm 7.0 mm

Predicted lateral deposition for 0.5, 1.9, 3.7, 4.7 and 7mm diameter particles from a GA200C fixed wing aircraft with a six duct spreader. Conditions - altitude 25 m, superphosphate, ground speed 54 m s-1, wind velocity 0 m s-1, wind angle 0° from flight direction

Distribution pattern GA200c aircraft

50 100 150 200 250 300 350 400

• 10
• 9
• 8
• 7
• 6
• 5
• 4
• 3
• 2
• 1

1 2 3 4 5 6 7 8 9 10 Lateral position (m) Deposition (kg ha -1)

DUCT1 DUCT2 DUCT3 DUCT4 DUCT5 DUCT6

Predicted lateral deposition from each duct for a GA200C fixed wing aircraft with a six duct spreader. Conditions - altitude 25 m, superphosphate, ground speed 54 m s-1, wind velocity 0 m s-1, wind angle 0° from flight direction

Distribution pattern GA200c aircraft

Modeled transverse fertilizer distribution of particles ejected from a Gippsland Aeronautics GA200C fixed wing aircraft with a six duct spreader – altitude 25 m, aircraft heading 360°, superphosphate, ground speed 54 m s-1, no wind and 4 ms-1 wind blowing from 315°

Distribution pattern GA200c aircraft

Modeled spatial fertilizer deposition of particles ejected from a Gippsland Aeronautics GA200C fixed wing aircraft with a six duct spreader – altitude 25 m, superphosphate, ground speed 56 m s-1, wind in case A) no wind, B) 4 m s-1 wind blowing from 315°

Deposition

50 100 150 200 250 300 350 400 1 2 3 4 5 6 7 8 9 10 Collector number Application Rate (kg/ha) Actual Predicted

• Predicted mean application 93 kg ha-1

(std. dev. 92 kg ha-1)

• Total quantity of fertiliser applied was

predicted to be 1.9 tons (CV) of 0.97.

• Within the application zone, 1597 kg of

fertiliser over 14.87 ha

• In the non-application zone, 193.3 kg of

superphosphate over 3.0 ha was applied.

• The remaining 103.9 kg was applied
• utside the trial boundary.

Predicted field scale application (kg ha-1) using automated hopper door control on a 25 ha trial site, 15 km North of Kimbolton, Manawatu, New Zealand.

Automated Control

• Predicted mean application rate was 107 kg

ha-1

• Total fertiliser applied, 1.8 tons at a CV of

0.93.

• Within the application zone, 1819 kg of

fertiliser over 15.59 ha,

• In the non-application zone, 71.1 kg of

superphosphate over 1.49 ha was applied.

• The remaining 45.7 kg was applied outside

the trial boundary.

• In the automated control system case, only

6% of the total fertiliser spread was outside the application area, compared to 16% in previous example

Table 1. Economic analysis for the application of superphosphate fertilizer on a 25 ha trial site, 15 km North of Kimbolton, Manawatu, New Zealand. Results are also extrapolated to a hypothetical 1500 ha (effective) farm scale. Superphosphate cost NZ$ 191 ton-1 (Ravensdown, 2005), target application rate 150 kg ha-1.

Parameter Trial Modeled Automated modeled Extrapolated Trial Extrapolated Automated Units Area of application zone 19 19 1500 1500 [ha] Area of non-application zones 6 6 474 474 [ha] Total fertilizer applied 1.9 1.8 150 145 [t] Fertilizer applied outside field boundary (a) 104 46 8211 3632 [kg] Fertilizer applied in non-application zone (b) 193 71 15237 5605 [kg] Total quantity of fertilizer applied off target (a + b) 297 117 23447 9237 [kg] Cost of off target application 57 22 4500 1737 [NZD $] Cost per hectare 3.0 1.1 3.0 1.1 [NZD $ ha-1]

Economics

401 340 389 325 311 316 Return ($/ha) 1.37 1.27 1.33 1.51 1.06 1.18 Fertiliser Response ($/kg) $ 1,008,618 $ 854,967 $ 979,285 $ 817,957 $ 783,681 $ 795,363 Profit $ 140,222 $ 128,558 $ 140,081 $ 105,952 $ 140,228 $ 128,547 *Cost Fert 738 671 738 542 738 671 Fert Used (T) 18 15 17 14 14 14 Mean SU/ha 45070 38585 43914 36246 36246 36246 Potential SU 24789 21222 24153 19935 19935 19935 Available Pasture 9846 8429 9593 7918 7918 7918 Mean kgDM/ha Full VRAT Reduced VRAT Simple VRAT Simple VRAT Inc Blanket Blanket Excludes Non responsive zones

Breakdown of Results Breakdown of Results

Fletcher Aircraft delivering Lime demonstrating shear fractured flow

Film courtesy of John Maber

The way forward

• Bulk solids flow affected through many means
• Product history & storage
• Moisture content and humidity
• Particle size distribution
• Compressibility & bulk density
• Temperature
• Better storage and on farm facilities
• More consistent product with less variability
• Better control of moisture and less fines to reduce

compressibility and variations in bulk density

• This should enable better control of on farm application

rates