Effect of impervious layers on soil water content. A practical demonstration of drainage constraints

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1 WATER DYNAMICS

2 Effect of impervious layers on soil water content A practical demonstration of drainage constraints

3 Effects of compaction on water infiltration - Cambs 10 mm.h -1 rainfall intensity on a 600 mm wide tramline track with zero infiltration, equates to 10 litres min m -1 the amount of which is illustrated above Infiltration where there was an obvious wheeling at or prior to sowing was almost zero Infiltration a few metres away where crop was growing evenly was orders of magnitude greater with all water seeping away within 60 seconds

4 The effect of pore size on water retention

5 Effect of pore size on water retention Hinge narrow end

6 Water drainage

7 Managing machinery on grassland and other soils Tim Chamen CTF Europe

8 Minimising damage - the principles Reduce the need to work in wet soil conditions Minimise tillage and use it wisely Choose and use tyres correctly Use tracks where viable Set up machinery combination correctly Narrow and fast or wide and slow? Lose weight when possible Give due attention to the operation of subsoiling Confine tracking Controlled Traffic Farming (CTF)

9 Addressing the principles Reducing need to work in the wet Time and machinery management attend to maintenance be fully prepared when conditions are right Consider reducing inputs fewer & shallower operations = more time available non-inversion or no-till

10 Addressing the principles Reducing need to work in the wet Maintain existing and consider introducing new drainage schemes

11 Addressing the principles Reducing need to work in the wet Increase organic matter levels (as covered earlier) grass leys cover crops reduced tillage high yielding crops retain residues if possible additions of manure and compost

12 Barrow 10 th May a lot of brown! Potential for cover cropping and extra feed?

13 Working on saturated soils Water is incompressible! can we compact a saturated soil? liquid flow low pressure, travel fast, avoid ruts is more research needed? how often do you need to travel on soils in this state?

14 Minimise tillage and use it wisely 2 key factors: 1.Rake angle 2.Depth/width ratio After: Godwin, 1974

15 Effect of rake angle on soil forces Implement face Rake angle Direction of travel Soil surface UPWARD DOWNWARD After: Godwin 1974

16 Effect of implement depth on soil forces More than double for 50 mm increase in depth After: Godwin 1974

17 Force, kn Effect of speed on soil forces % increase for 2x speed HORIZONTAL 1 VERTICAL After: Wheeler and Godwin, 1996 Speed, km/h

18 Addressing the principles Choosing and using tyres correctly Learn the principles manufacturer s literature and training workshops tyre data book or pdf lowest inflation pressure for load and speed Rule of thumb for tyres pressure at the surface reduces to half its value at a depth equivalent to the width of the tyre P ½P

19 Choosing the right tyres Axiobib - 20% more load at same pressure Xeobib 40% more load at same pressure

20 Tyres have very different characteristics

21 What can be achieved Combine on standard tyres

22 What can be achieved Same day, same combine but on low pressure tyres

23 Be inventive!

24 A more expensive option! (will talk about tracks in a moment)

25 Tyres what s the correct inflation pressure? Example from tyre data book 18.4R34 tyre Tyre rolling radius, mm Max speed, km/h Load, kg at: Pressure 0.8 bar 1.0 bar 1.2 bar

26 Recorded pressure, bar Tracks Lay down area in length rather than width but pressure not even under this length 3.0 Run No. 4\3\1\009 Ground pressure time history combine track combine rear wheels Time, secs Accepted thinking: most stress under tracks is dissipated in the topsoil

27 Tracks Advantages Less area tracked on each pass More efficient pulling power 4% compared with 12% slip Less rutting Disadvantages Heavier than wheels Can do more damage to crops on turning More expensive than wheels 25% price premium compared with equivalent wheeled tractor Good Not so good

28 Setting up machinery combinations properly Mounted cultivators correct ballasting 3-point hitch geometry top link position should ensure weight transfer onto rear wheels Trailed cultivators correct ballasting particularly important with single tracks

29 Narrow and fast or wide and slow? Compaction influencing factors Narrow and fast compaction is time dependent it doesn t happen instantly usually means less wheel slip = less damage probably lighter tractor Wide and slow lower traffic intensity greater risk of wheel slip probably heavier tractor more risk of deeper compaction

30 Keep an eye on weight Take time to remove excess weight Not always easy or appropriate and can remove too much!

31 Depth, cm Subsoiling can make compaction worse! Penetration resistance, MPa "As found" After subsoiling Large tractor Large + medium tractor Tracked tractor TT + medium tractor 40

32 Subsoiling Consider carefully: before during after

33 Mole ploughing might be a better option After subsoiling or mole ploughing is a good time to think about controlled traffic farming (CTF)

34 What is CTF? any system that confines all tracks to least possible area of permanent traffic lanes CT is NOT prescriptive about tillage CT is NOT just about keeping tramlines in the same place Commitment to continual improvement

35 Predicted pressure at 0.5 m depth, bar t vehicle Why CTF? 21 t vehicle Timeline from the 1930s to the present day 850 kg Horse R /70 R /65R /50R32

36 Conventional systems track a big area Traditional: Average: 85% tracked Wheat Czech Republic straw baling straw carting grain carting Kroulik et al, 2011

37 And it s not just cultivated soils!

38 Wheels have a big impact! Same field one week later!

39 Local traffic patterns

40 CTF can turn tracking on its head! CTF: 85% not tracked

41 but, CTF has some drawbacks It needs careful planning and attention to detail matching track gauges matching implement widths It requires investment in auto-steer It introduces an element of inflexibility Probably needs a change in agronomy less and shallower tillage different methods of weed control

42 Only an RTK GNSS system provides repeatable positioning GNSS satellites e.g. GPS, GLONASS Galileo L2 L2 L2 x Geo-stationary EPHEMERIS ERRORS satellite RTK Base Network centres GNSS global navigation satellite system

43 GNSS would it pay? In 20 passes, approx 16 m error

44 Web-based software Optimising direction of traffic lanes Calculation of tracked areas

45 BENEFITS OF CONTROLLED TRAFFIC

46 Benefits of CTF Increased crop yields % increase in yield by crop type under controlled compared with random traffic Numbers in brackets denote number of research results from which data were taken

47 Yield of Grass in Wheel Tracks as % of Yield in Untracked Area, No Traffic 1 Pass 3 Passes Sig. First Harvest *** Second Harvest NS Third Harvest NS Total *** Source: AFBI Hillsborough

48 Benefits of CTF Lower energy inputs Depth of operation, mm Draught savings, % 100 (4 ) 200 (8 ) 500 (20 ) Overall savings in energy for crop establishment can be as high as 70%

49 Benefits of CTF Improved water infiltration Randomly trafficked 4 x increase in infiltration with CTF Better soil structure Over 30% more plant available water CTF

50 Reduced on-farm costs East Hendred Benefits of CTF

51 Improved soil structure Zero traffic for 15 months 2 passes post harvest 3 passes post harvest

52 Will the benefits out weigh the disruption to the soil eco system? Is it economic to subsoil? Have we got time? Will subsoiling let out too much moisture? Is there compaction? Are conditions right or will the wings smear? What depth to subsoil? Benefits of CTF Makes farming easier Farming gets simpler with CTF Quote from Julian Gold, East Hendred, Oxfordshire

53 Management of intermediate wheel tracks

54 CTF system for grass

55 Baling in CTF system - dropping or moving bale to the right place

56 Grassland CTF 65% Kroulik, M., 2012, Sabbatical Study at Harper Adams University, Danish Conditions 80% of grass - contractors Cut grass 4 times/year Slurry tanker 50-60t Forage Harvester 10-15t Tractor with trailer 30-40t Benefits Less tracks Quicker re-growth Grass lasts longer Slurry injection to uniform depth Less injector wear Cheaper Less fuel Higher capacity Kjeldal, M., 2013, Contractors improve yield and make better feed quality by use of CTF in forage grass, 1st International CTF Conf, Toowoomba, Australia

57 Harvesting maize can be a lottery! Very poor conditions but often self-inflicted! Good conditions

58 - but it needn t be! OutTrac CTF System Operating from firm traffic lanes 3.35 m harvester track gauge Soil with better infiltration and drainage 6 m, 9 row maize planter, 0.67 m rows 2.01 m tractor track gauge

59 TwinTrac 4.8/24 m system for maize

60 Does CTF work? I don t know anyone who s turned their back on it!

61 GRASSLAND CASE STUDY

62 Grassland Case Study Acknowledging Farmers Weekly Academy 180 ha organic dairy farm, West Yorkshire 260 cows on grass for 10 months of year paddock grazing mostly leaf with 27% protein 3000 ft of concrete sleepers gets cows to paddocks electric fenced to keep cows on track Close eye on sward first signs of damage, brought back onto hard standing 4 hours grazing sufficient, 12 h max on paddocks

63 Grassland Case Study Aerator used in autumn and spring conditions must be right not too dry or wet removes water from surface

64 Grassland Case Study Benefits improved sward productivity less silage used (2.5t/day) less concentrate milk yield increased extended grazing increased bottom line by up to 8000 per month BUT regular grass measurement needed to keep dry matter intake up

65 Restricting access time to pasture Access for 48 cows Full (22 h) 2 x 5 h 2 x 3 h Alternating Full/2x3 Result: No difference in milk or milk solids yields 13.2 and 1.15 kg/cow/day respectively Cows learnt to graze more aggressively After Dr Emer Kennedy, Teagasc, Moorepark