Establishment (Ploughing vs Min Till)

Weeds
1. min till traditonally increased grass weeds and reduces BLW
  1. 90% of grass weeds germinate in top 2-3 cm of soil so increased with MT
  2. small BLW germination from seed bank at any one time, min till only encourages top seeds to germinate deep ones never initiated so reduce
  3. seed bank reduces with min till as seed are not being continously burried
2. vol. rape, forget me knot and field pansy reduce with MT, AMG and chickweed increase.
3. ploughing may increase dormancy of a seed as dormancy develops in response to rapid burying of seed after harvest
4. for sterile brome ploughing better as its seed only survives one year
  1. also couch grass as discs chop rhizomes rather than bury encouraging spreading
5. control
  1. rotation breaks up chemistry
  2. stale seed bed technique most effective for MT
    1. meadow grasses, bromes, black grass, italian ryegrass and volunteers most effected
6. Herbicide efficacy
  1. best with fine, firm, clod free seed beds, low OM.
  2. Propyzamide (KERB) will exhibit poor control on black grass germinating from depth or that which is below activity layer, shallow min till or no till provides good results, best with no till. autocast very good suggesting trash not a problem
    1. Cousins developed super low disturbance min till deep till legs to help efficacy
  3. ploughing mixes up seed bank, widening gene pool of germinating seed, min till keeps sam species in top soil increasing resistance within germinating weeds if used annually
Pests
1. Beneficials increase
  1. predatory ground beetles and parasitic wasps increase with MT DEFRA
  2. carabid beetles increase, possible reductions in slug numbers
2. Slugs
  1. ploughing kills slugs and eggs
  2. straw rake reduces no.s and eggs
  3. leave fine, firm, well consolidated seed bed, rolling in moist cool condisitons also kills slugs on surface
  4. Increase in volunteers, lossed seed on surface provide alternative food source and increase predatory beetle numbers
  5. increase in slug pellet use
    1. nema slug offers effective alternate control over slugs with beneficial nematodes but commercail ability of the product (gardens mainly) is limiting
3. Wire worm
  1. years of min till increasing wire worm in arable rotations
4. Aphids
  1. MT had less BYDV and aphid no.s compared to CT
  2. MT plots with more incorporated straw had even less BYDV and aphid no.s as less visual cues for aphids as plants masked with straw and residues
    1. increase in OM over time though makes top soil darker and green more visible
    2. need to control green bridge or aphid landing increases
  3. predators also increase with MT
Diseases
1. Wheat/cereals
  1. Takeall
    1. CT 42% incidence, MT 37% over 3 year seasons
    2. however, with compaction, volunteers and grass weeds the better rooting experiecned with MT won't be as effective in reducing take all, increase in herbicide use
  2. Eye Spot
    1. trash borne, saprophite but 6% less incidence compared to ploughing over a 3 yr period
    2. fungi does not overwinter well close to surface, shallow buried trash will encourage disease though
  3. Fusarium
    1. problem with MT and maize rotation
    2. plough between maize and wheat, also reduces weeds when rotational
    3. 2% higher incidence over 3 years with MT
  4. cephalosporium leaf stripe
    1. rare with CT possible with MT
    2. fungi slow growing over many years on cereal trash
    3. common on heavy poorley drained soils, wheat crops successive over 2 years
    4. ploughing reduces incidence as growth disrupted 2-3 year break also good, OSR and oats and barley which do not support the fungi
  5. Ergot
    1. develops on grain head, in MT remains on surface, infects next crop
    2. ploughing reduces incidence as the fungi rarely survives more than 1 year in ground
2. OSR
  1. Light leaf spot and Phoma
    1. saprophite pathogen, MT increases , up to 2 years survival on stubble, 10-20% yield loss, worth £11-31 million per year in UK
    2. needs 20 days of rain in autumn to sporalate, early drilling with min till can reduce as crop establishes quicker when sown earlier in season so in a better position to tolerate infection as rain less in earlier sowing (traditional)
    3. deep ploughing reduces , 1 in 3 rotation
  2. Sclerotinia
    1. sclerotia survive in soil, become less viable as length of time buried and depth increase
    2. ploughing reduces, but ploughing before rape may increase as buried sclerotia brought back up
3. volunteers/weeds between crops can sustain disease burdens, volunteers higher in MT need controlling, stale seed bed technique
Soil
1. structure improved with min till, soil quality organisation suggest only the minimum amount of tillage should be done to support establishment and increase structure
2. increased OM, adding stabiliyt, increased soil life and quality
3. tillage practise should be suited to soil type, easily compacting soils may not suit MT (especially shallow) and in wet years MT may not work at all, a comprimising approach within UK is needed
4. increase in earthworm numbers, added soil health
5. Erosion and Run-off
  1. build up of OM reduces run off and erosion, MT on silty clay loam reduced run off by 48% and erosion by 68% compared to CT
  2. higher filtration in MT
  3. contour tillage with MT redutions of 70% in run off and erosion but not significant (stevens et al, 2009)
  4. stevens et al 2009, no sign. differences in erosion or run off from MT vs CT exp. sediment loss, or toal phosphorous loss
    1. increased losses of available phoshourous within top soil due to high concentrations held in OMand top soil
Yield
1. banding min till rape 0.5t/ha increase
  1. 1t/ha higher than ploughing
2. christian and bacon, 1990, long term trial over crops, soil types and cultivations, no significant difference on average but the only sig. differences which did occure were where min till was higher, suggesting that when yield was lower it was not dramatically reduced by the practise
3. Hao, 2001, also found no significant differences between MT and CT, highlighted how min till benefits root crops as well as cominable on clay loamy soils
4. HGCA, OSR autocast better than CT, MT inbetween
5. HGCA trials (KNIGHT) over early 2000's show MT highest yielding on light soils, variability within systems increase as clay content increases
Drilling
1. Presents possibilities for direct drilling or different drilling methods such as banding for OSR or strip tilling
  1. Experience on placment in cambridgeshire on a field trial showed a difference of .5t/ha in banded vs broadcast OSR
  2. direct drilling can not be as reliable in poor draining soils and compacted soils
Nutrition
1. increase in OM increases carbon to nitrogen ratio, increasing the amount of denitrification by microorganisms, reducing the amount of available nitrogen in the soil
2. OM increase water holding, structure, plant health and root development
3. reduced run off so more availabiltiy
4. increased loss of phoshourous from top soil with incresed OM
Biodiversity
1. increased earthworm numbers and other beneficial insects, such as ground beetles and parasitic wasps
2. reduced erosion and run off stabilising habitats
3. increased trash and om beneficial to ground nesting birds
4. increase in pesticide use such as seed treatments effecting birds eating seeds and bees on attractive crops such as OSR, (modesto clothianidin neonicitinoid) seed treatments may increase with min till to protect against pest and diseases as fields are drilled earlier in favourable conditions for certain pests and diseases which require warm weather e.g. aphids
Expenses
1. More expensive equipment
2. Greater reliance on pesticides
  1. Slug pellets
  2. Herbicides
    1. May be cheaper though such as more use of glyphosate
  3. Seed treatments, fungicides
3. Horsepower requirements for individual tractors may go up increasing purchase price
Savings
1. Time
  1. Min till increases the timelyness of operations increasing the area covered per day and per date such as finnishing in Oct or Nov where the amount of time to reach 150 day degrees for emergence is reduced from 26 Nov to 15 Oct (HGCA wheat growth guide)
    1. drilled into warmer seed bed earlier
  2. plough 60150 mins/ha min till shallow 25-60mins/ha direct drill 20-30 mins/ha
  3. Nix state a 1.2-0.9 hr saving/ha
2. Fuel
  1. ploughing at 72p/l £22-36/ha adapted from Bailey, 2007. Shallow min till £18-20/ha, Direct drill £6-8
3. Labour
  1. Nix state a 1.2-0.9 hr /ha saving
  2. £10/hr for above average operator around £10/ha saving
4. Money
  1. plough £70-100/ha min till shallow £50-60/ha direct drill £20-30
5. Horsepower requirement, smaller tractors and cheaper purchase price, but may need more tractors
6. HGCA trials show MT cheaper on light soils but CT cheaper on heavy soils
Legislation
1. Soil protection review praises min till in circumstances where erosion and run off can be reduced
2. Seed treatment stewardship, no treated seed on surface, if broadcasting and min tiling need to cinsider this

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Establishment (Ploughing vs Min Till)

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