Overcoming soil constraints Stephen Davies and Glenn McDonald, DPIRD

Transcription

1 Overcoming soil constraints Stephen Davies and Glenn McDonald, DPIRD

2 Soil Constraints in the South-west HRZ 1. Introduction to Constraints Steve Davies 2. Managing soil water repellence Steve Davies 3. Soil acidity Glenn McDonald 4. Soil amelioration Glenn McDonald 5. Conclusion

3 Soil Constraints in the South-west HRZ Duplex Sandy Gravel Loamy Gravel Shallow Loamy Duplex

4 Soil Constraints in the South-west HRZ Soil Constraint Soil water repellence susceptibility Darling Range to South Coast (1.52M ha) Zone of Rejuvenated Drainage (2.42M ha) Southern Wheatbelt (3.29M ha) Stirlings to Ravy (0.6M ha) 47% 54% 51% 60% Topsoil acidity 64% 57% 56% 58% Subsoil acidity (15-25cm) Subsurface compaction susceptibility 87% 79% 54% 55% 71% 77% 57% 58% Soil water storage 25% 38% 48% 48% Waterlogging/ Inundation risk 10% 16% 11% 10% van Gool 2016, DPIRD Resource Management Technical Report 399

5 Managing soil water repellence 1. Banded wetters furrow or seed placed 2. Blanket wetter, every second year 3. On-row sowing 4. One-way ploughing, +/- pre-emergents 5. Mouldboard ploughing, +/- pre-emergents

6 Drone imagery 8/06/ /06/ /07/2017 6/08/ /08/2017 2/10/2017

7 Ground Cover % by Drone

8 Ground Cover % by Drone

9 Managing soil water repellence Wheat

10 Managing soil water repellence

11 Banded soil wetters yield summary Soil type No. trials Average yield change with wetters (kg/ha) % Yield change Yield change range (kg/ha) % Dry sown Loamy gravel to Sandy gravel to Sand to Cereals 1993 (Crabtree) Soil Type to Average yield change with wetters (kg/ha) % Yield change Dry Wet Dry Wet Loamy gravel Sand

12 Managing Soil Water Repellence Option Establishment Vigour Grain Yield Grain Protein Soil types On-row sowing Yes Sometimes Sometimes No All Banded wetter Yes Yes Yes No Gravel Blanket wetter Yes Sometimes Yes Sometimes Gravel Ploughing Yes Variable Yes Yes Sand/Gravel Claying Yes? Yes? Sand/Gravel +Wetter Control +Wetter Control Ploughed

13 Subsoil Acidity Approx kg lime/ha/yr depending on system ph is a log scale ph = x acidity at ph 5.0 Small applications consumed at surface Higher applications take time to impact subsoil Mechanical intervention only method to get lime deeper quickly

14 Cranbrook, 2018 Bleached layer with low OM Roots penetrating into clay layer not toxic Ripped to clay 2016 CTF Approx ph (CaCl) Surface (0-5cm) 6.0 OM & sand (5-40cm) Clay (40+ cm) Inclusion plates??? Lime, OM MBP, OWP, plozza, or spade??? Lime, OM Erosion Delve to mix clay???

15 Inclusion plates to move lime Moora (Yanda), t/ha lime Top 10cm removed Immediately after ripped Topsoil slot from inclusion plate ph (water) ph (water) Wayne Parker, DPIRD, GRDC DAW00243

16 Visual score roots (Mt Walker) Rip with slots Not ripped Jenni Clausen, DPIRD, GRDC DAW00242

17 Penetrometer Jenni Clausen, DPIRD, GRDC DAW00242

18 Visual score roots Not ripped Slotting 4.5 t/ha lime Ripped 4.5 t/ha lime Ripped 7.6 t/ha gypsum Tested gypsum sample: 30% purity Jenni Clausen, DPIRD, GRDC DAW00242

19 ph 1:5 h2o rip with slotting 4.5 t/ha lime ph 1:5 h2o rip 4.5 t/ha lime Tip of inclusion Jenni Clausen, DPIRD, GRDC DAW00242 Rip seam

20 Paddock variability Variability is biggest problem for strategic tillage or amelioration in South Western Wheatbelt. Very easy to get a negative result. Hard to summarise R&D into clear messages... There is no normal Gravels aren t gravels West River, 2013 still dealing with negative effects of tillage 4 years later

21 Wagin Ripped into hostile subsoil and caused problems Hostile clay brought up Rip lines increased waterlogging Seed placement deeper Caused root rot

22 Variability Sth Stirling Nth Stirling Wickepin Cranbrook west Brookton (spaded)

23 Variability - Boscabel Soil variability (arrows) Generally positive response (blue circles) Also negative (red circles) Colour difference is about half tonne/ha Terraland ripper/delver 2016 Wheat

24 Yield t/ha Sandy clay over loam Broomehill Long-term ripping trial 2015 Wheat 2016 Barley Highly variable! 2016 LSD 10% Topdress 0.8 Ripping*Topdr Nil TS Nil Lime 5t/ha Manure 10t/ha

25 Broomehill East Assessed area was sandy duplex Large variability (grey clay to deep pale duplex) difficult to manage MBP better both years BUT MBP was observed to be worse when grey clay

26 Broomehill East Mouldboard plough

27 response from unripped % Sandy grey clay duplex Ongerup yield response * * Significantly different to unripped Unripped 2.74 t/ha 2.77 t/ha 0.76 t/ha * * 2015 Wheat * 2016 Barley 2017 Canola 10 * TS

28 Sandy grey clay duplex - Jacup

29 Grain yield (t/ha) Ripping 300mm Nyabing cm sand clay 1.1 t/ha 20cm sand clay 0.3 t/ha 15cm gravel sand clay 0.5 t/ha 10cm sand clay 0.24 t/ha 35cm sand clay Control Deep ripping Hobley Ramm (1) Ramm (2) GSARI Browne barley barley barley wheat wheat Brenda Shackley, DPIRD, GRDC

30 Summary Southern Deep Ripping Trials Soil Type Avg Yield response % Range Yield Response % No. trials Sand/gravel Deep sand Loamy duplex Sandy gravel Gravel* 7 1 Sandy loam duplex# 9 1 Average 15% yield response Jeremy Lemon, DPIRD, GRDC DAW00242

31 Looking for new R&D sites to monitor Actively researching ripping and gravel soil management options Gravelly sandy duplex (40cm to clay) West Kendenup Grower aim; mix topsoil OM with subsoil Not disturb clay subsoil 2018 planned trial Ripping Inclusion plates (250mm) Wings (1m & 2m) Inclusion plates wings

32 - Preserving ripping response Standard no-till system 1 DIAGRAM OF WHEELTRACKS ACROSS PADDOCK 39% Coverage Tractor1 Air cart Tractor1 Chaser Bin Tractor2 Boom Spray Tractor2 Harvester DISTANCE ACROSS PADDOCK (m) 45ft header, 55ft seeder, 100ft boom

33 Compromise CTF system 1 18% coverage Tractor1 Air cart Tractor1 Chaser Bin Tractor2 Boom Spray Tractor2 Harvester ft header, 60ft seeder, 120ft boom DISTANCE ACROSS PADDOCK (m)

34 Fully matched CTF system 1 11% coverage Tractor1 Air cart Tractor1 Chaser Bin Tractor2 Boom Spray Tractor2 Harvester ft header, 40ft seeder, 120ft boom DISTANCE ACROSS PADDOCK (m)

35 Conclusions Wetters do work on gravels but tillage more reliable when repellent soil Lime needs help getting into subsoil Ripping is usually positive on most soil types but responses vary Before amelioration Dig holes, map zones, assess soils, plan strategy Deeper ripping without subsoil knowledge is unwise Whole of paddock amelioration unlikely to be positive over whole paddock CTF is needed to preserve investment in deep ripping Soil constraints research is an active area happy to help anyone

36 Acknowledgements GRDC Soil Constraints West Projects DAW00244 Soil water repellence DAW00243 Soil compaction DAW00242 Subsoil constraints Thanks Justin Herb Elliott (Boscabel) Jono Clifton (Sth Kojonup) Tim Harrington (Darkan) Kim Oliver (Nth Stirlings) Ben Sprigg (Cranbrook) Craig Bignell (Broomehill) Scott Thompson (Broomehill) Wes Harding (Ongerup) Stuart Bee (Jacup) Emma Russell (Southern DIRT) Jenni Loveland (Gillamii Centre)

37 Grains Research and Development Corporation (GRDC) A Level 4, East Building, 4 National Circuit, Barton, ACT 2600 Australia P PO Box 5367 Kingston, ACT 2604 Australia T F #GRDCUpdates

38 Gravels Muradup large scale Discs as good as anything in no advantages over nil Concl nothing is certain Gravels and then there s gravels Ripping doesn t always work Stumps/roots/rocks Jeremy Lemon, DPIRD, GRDC DAW00242