Fertiliser Use in New Zealand Section 13. Fertiliser Application Groundspread

Transcription

1 Fertiliser Use in New Zealand Section 13. Fertiliser Application Groundspread This presentation is aimed at supplementing you notes to Section 13 of the on-line study guide.

2 Fertiliser Spreading Costs Fertilisers kgha -1 $T -1 $ha -1 $T -1 $ha -1 $T -1 $ha -1 Superphosphate Potassium Chloride Nitrogen (Urea) , Ag Lime Total Table 1 Annual fertiliser recommendations for a Waikato Dairy Farm, derived from Lawrence (2007). Price changes Superphosphate Potassium Chloride Nitrogen (Urea) Ag Lime

3 Spreader Types. Truck mounted spreaders. Majority of fertiliser spread using these machines Favoured by contractors. Reasonable speed and range. A large range of products can be spread. Lime, Urea, superphosphate, compounded fertilisers. Chicken manure. Many now using GPS Guidance and some computer control to give more even spreading.

4 Tractor mounted Mostly European imported machines used by cropping farmers, some less sophisticated New Zealand built machines. Amazone, Bogballe, Sulky.

5 Basic Operation, Amazone Most spreaders have two contra rotating discs. Speed of the discs can be controlled within bounds for different products. With compounded fertiliser the flow off the disc is by fertiliser flowing up the vanes and being flung as a stream from the vanes. Angles of vanes can be adjusted. Drop on point is crucial to accurate spreading.

6 Boundary and Edge spreading. Amazone In order to avoid spreading over boundaries or into waterways a system of shutters is used to redirect the spread pattern.

7 Other spreaders Trailed machines, larger capacity than tractor mounted, typically 6-8 tonne capacity. ATV mounted: Small spreaders suited to smaller areas where farmers wish to spread products such as urea. Disc driven from the wheel, as long as consistent speed maintained then will performance to stated values. Can give farmers advantage in strategic application of nitrogen.

8 This is NOT variable rate nitrogen!! Achieving accurate spreading is economically important. There are a number of testing systems / regimes used around the world to measure the transverse distribution of fertiliser from spreaders. In New Zealand the system is called Spreadmark. This system provides a standard that is comparable to other systems around the world. The Fertiliser Quality Council of New Zealand provides governance for this system and Fertmark. Fertmark is concerned with the chemical properties of the fertiliser, to make sure that the fertilisers contain the amount of nutrient stated on the labelling. Spreadmark is designed to avoid problems like this. There is also an Association of Ground Spreaders, and they are concerned with driver training and promoting high quality and consistent spreading.

9 Test Layout

10 Application Rate (kg/ha) Transverse testing Transverse distance (m)

11 Testing Comparison Results Product: Urea (46%N) Rate: 100 kg/ha Test Method Bout width (15% CV) ASAE (4m trays) 25.9 ASAE (0.5m trays) 27.8 ISO(i)/Spreadmark 13.0 ISO(ii) 25.9 ACCU-Spread 26.5 European Standard 25.2 Difference 14.8

12 Creating as-applied surfaces Creating as-applied surfaces Available Data GPS track log Spreadmark transverse test Not useful as independent data Combined to create an application surface

13 Defining Spreader Footprint 120% 100% 80% 60% % 20% % Spreader Distribution Point If the actual spread pattern is known through a static test then the spread pattern can be accurately modelled and mapped. This could also be utilised to more accurately control the spreader. Reference: Modeling of Fertilizer Distribution Using Measured Machine Parameters H. G. Lawrence, I. J. Yule, Transactions of the ASABE, (50)4:

14 Groundspread performance Optimised driving pattern, CV(%) 27 (b) Legend kg/ha Spread Line In trial of 102 dairy paddocks, average CV was found to be 37% for typical 2 ha paddocks

15 Factors Affecting Field Performance Field size and shape (Large effect) Perfect spread pattern (Smaller effect assuming it has passed transverse test) Perfect driving (Largest effect) Starting and stopping position (surprisingly large effect especially in smaller paddocks)

16 The effect of incorrect starting and stopping positions Automatic stop and go (b) (a) Original driving pattern, CV(%) 38.5 Legend kg/ha Spread Line Optimised driving pattern, CV(%) 25

17 Actual Range: kg/ha

18 Paddock Info - 19 Paddocks ha - 17 uniform, 2 non-uniform Field Application - Target Rate = 80 kg ha -1 Results Farm B - Farm average = 60.9 kg ha -1 Field CV - Overall = 43.0% % 58.9%

19 Results Farm C Paddock Info - 41 Paddocks ha - 20 uniform, 21 non-uniform Field Application - Target Rate = 80 kg ha -1 - Farm average = 68.1 kg ha -1 Field CV - Overall = 36.9% % 62.3%

20 Results Summary from 102 Paddocks The effect of paddock size and shape on field application CV Greater spreading uniformity when paddock size increases. Far greater variation in Field CV than that measured from a single transverse test

21 Individual field CV (%) EFFECT ON NITROGEN USE: AS CV INCREASES THEN N USE EFFICIENCY DECREASES. 70% 60% 50% 40% 30% 20% y = x R² = % 0% N Response (kgdm kgn -1 ) Theoretical N response of kgdm/kgn applied at 80kg/ha Urea (46% N)

22 Consider losses from inaccurate N spreading Av. N C.V. % Avg N response (1) Production gain kg DM ha-1 Production Value $ 2006 (2) Production Value $ 2008 (3) Theoretical N Applied Actual N Applied Optimised N Applied Difference Theoretical - Actual Theoretical - Optimised Optimised - Actual (1) Calculated from Ball and Field (1983) (2) Pasture Value based on $0.176kg DM (3) Pasture Value based on $0.25kg DM

23 CONCLUSIONS Accurate application of appropriate fertiliser is very important. Accuracy: Fertmark, Spreadmark. Setting of machinery, operator and use of technology such as GPS. Appropriateness: Use of modelling techniques such as Overseer to allow the correct level of nutrient application to be calculated, when all environmental factors have been considered. (soil types, climate, farming system)