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 2,500 2,000 1,500 Kg/ cubic metre As ReceivedBulk Density Kg/m³ Tap Density Kg/m³ Loose Bulk Density Kg/m³ 1,000 500 0 A B C D E F G H I Limes

Jenike Shear Cell Some answers after some time • Angle of internal friction angle of wall friction

So me 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

Aerial topdressing technology Where are we headed? Structure of presentation • Justification for modelling work • Overall aim - VRAT • Modelling particle ballistics • Improving spreading techniques

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 700 600 Actual Predicted 500 Application rate (kg ha -1 ) 400 300 200 100 0 -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) 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.

Distribution pattern GA200c aircraft 250 200 Deposition (kg ha -1 ) 0.5mm 150 1.9mm 3.7 mm 4.7 mm 7.0 mm 100 50 0 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9 10 Lateral position (m) 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 400 350 DUCT1 300 DUCT2 DUCT3 DUCT4 DUCT5 250 DUCT6 Deposition (kg ha -1 ) 200 150 100 50 0 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 1 2 3 4 5 6 7 8 9 10 Lateral position (m) 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 °

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 °

400 350 Deposition 300 Application Rate (kg/ha) 250 Actual Predicted 200 150 100 50 0 1 2 3 4 5 6 7 8 9 10 Collector number 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 outside the trial boundary.

• Predicted mean application rate was 107 kg ha -1 Automated Control • 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 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.

Economics 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 . Trial Automated Extrapolated Extrapolated Parameter Units Modeled modeled Trial Automated 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 $] [NZD $ ha -1 ] Cost per hectare 3.0 1.1 3.0 1.1

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

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