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Summary of soil results | Water for Profit
- 1. 1 Dr Bill Cotching Dr Marcus Hardie Water for Profit Readily available water storage & irrigation interval
- 6. Duplex soils Gradational soils Ferrosols Hydrosol28 – 42 mm 17 – 20 mm 16 – 26 mm 18 - 25 mm 42 mm
- 7. Sandy loams Clay loams Big water storage 28 – 42 mm Small water storage 17 – 20 mm Small water storage 16 – 26 mm 9 farms 5 farms 5 farms RAW in root zone
- 8. Soil structure ? 28 – 42 mm 16 – 26 mm Duplex soils
- 9. Drainable porosity = large soil pores Duplex soils
- 10. Drainable porosity = large soil pores Good Not good
- 11. RAW’s are different on different soils. So what for irrigation interval
- 12. Soil type RAW mm Daily ET0 (November - March) mm Campania Fingal Cressy Smithton Duplex sandy loam 28 - 42 4.4 Duplex sandy loam 17 - 20 4.2 Gradational 16 - 26 4.5 Ferrosol 18 - 25 3.7 Hydrosol 42 3.7
- 13. Soil type RAW mm Daily ET0 (November - March) mm Irrigation interval days Campania Fingal Cressy Smithton Duplex sandy loam 28 - 42 4.4 6 - 10 Duplex sandy loam 17 - 20 4.2 4 - 5 Gradational 16 - 26 4.5 4 - 6 Ferrosol 18 - 25 3.7 5 - 7 Hydrosol 42 3.7 11
- 14. Soil type RAW mm Daily ET0 (November - March) mm Irrigation interval days Daily Et0 Max mm Campania Fingal Cressy Smithton Duplex sandy loam 28 - 42 4.4 6 - 10 9.9 Duplex sandy loam 17 - 20 4.2 4 - 5 8.6 Gradational 16 - 26 4.5 4 - 6 8.8 Ferrosol 18 - 25 3.7 5 - 7 6.4 Hydrosol 42 3.7 11 6.4
- 15. ETc and crop coefficient Crop Kc ini Kc mid Kc end Pasture 0.4 0.85-1.05 0.85 Broccoli 0.7 1.05 0.95 Carrots 1.05 0.95 Potato 1.15 0.75 Beans 0.5 1.05 0.9 Lucerne 0.4 1.2 0.95 Source - http://www.fao.org/docrep/X0490E/x0490e0b.htm Crop coefficients, Kc, for non stressed, well-managed crops for use with the FAO 56 Penman-Monteith ETo.
- 16. Irrigation system capacity • The system capacity is the maximum possible rate at which the machine can apply water to the irrigated field area • Expressed in mm/day - NOT the depth applied per pass (mm) )(mareairrigatedField (L/day)rateflowpumpDaily CapacitySystem 2
- 18. How wet does your soil have to be to be ‘full’ ?
- 19. 36 – 44 % 48 % 48 % Duplex soils Gradational soils Ferrosols Hydrosol Topsoil water content at field capacity (full after irrigation)
- 20. 17 % 17 % Topsoil water content at irrigation start up
- 21. 17 % 17 % 25 % Topsoil water content at irrigation start up
- 22. 17 % 17 % 25 % 32 % 37 % Topsoil water content at irrigation start up
- 23. Readily available water storage & irrigation interval RAW varies a lot, even on the same soil type (17 – 42 mm in top 30 cm of sandy loams) RAW, crop ET & irrigation system capacity all determine irrigation interval Soil water content at ‘full point’ is surprisingly wet And also at ‘refill’ point on many soils (17, 25, 32, 37 % on sandy loams)