Claydon Straw Rake to Improve Weed and Slug Control?

August 7, 2012

The past five years have been a great learning curve for us in how to direct drill crops and avoid moving too much soil.  In fact it is the complete opposite of the previous farming system where the plough was used to move top 6-9 inches of soil across the whole field.  Some farmers refer to direct drilling as ‘zero tilling’ though it does depend on the drill used.  The following two links are useful: http://en.wikipedia.org/wiki/No-till_farming and http://no-tillalliance.co.uk/#.

The decision not to invert the soil does lead to problems with what to do with the crop residue left after combining, particularly in Oil Seed Rape where the straw was baled.

Crop residue after harvest

Crop residue after harvest

In wet years slugs can rapidly multiply under the straw and stubble left behind.  Slugs can cause massive damage to young plants or even crop failure.  Control is mainly achieved through using slug pellets though rolling the seedbed after drilling will help. A second problem is trying to get weed seed to chit so that they can be controlled.

Slug in crop residue

Slug in crop residue

Straw harrowing is a fast and very low cost operation that can be used just once or a number of times to create a micro-tilth for fast weed germination, hoe out weeds and kill slugs before drilling whilst retaining the moisture, organic matter and structure in the soil.  The picture below is the first time the rake is used on the farm.

New rake being used on Oil Seed Rape Stubble after baling

New rake being used on Oil Seed Rape Stubble after baling

The aim is to move the residue, and create enough tilth for weed seeds to germinate. The harrow levels straw and damages slug nests and their eggs, moving straw trash and drying out the slug nests

The harrow encourages weed seeds to germinate at the top of the soil, giving fast & even germination and a great kill strike rate from re-harrowing or spraying.  Below shows the split in the field where the rake has been used and has still to pass.

Rake pass moves the crop residue

Rake pass moves the crop residue

We hope the rake will result in a relatively cheap way of reducing the cost of slug and weed control.

Does Direct Drilling Pay?

January 2, 2011

If there was only one correct way to establish wheat, every arable grower would do the same thing.  As it is, each farmer has adapted the cultivation and drilling equipment and techniques used to suit the soil, climate and topography of the individual farm.

When we set off down the direct drill route (a radical change from ploughing and following with a powerharrow / drill combination) there was always the nagging doubt or fear of exchanging a proven system to one that may not work.  Those involved in agriculture in the 1970’s will remember the failed experiments with direct drilling.

Using the Christmas period to sit down and work out the costs for the last harvest (2010) has proved to be a useful experience if not necessarily giving the results we wanted.  On the positive side the Oil Seed Rape, Linseed and Winter Beans established well using the Claydon Direct Drill and we have no intention of using any other method.  Whilst Winter Linseed was a novel crop to us, the OSR and Beans yielded well and were above the 5 year average.  The wheat is more of a dilemma.

We compared the yield of 6 fields,  3 established via the direct drill and 3 using the traditional plough and powerharrow / combination route all growing a veriety called “Alchemy”.  This is not a scientific experiment, more of a back of an envelope job with numerous variables not accounted for.  However the yield benefit of ploughing appears to be 0.35t / ha which at £150 / tonne is approximately £52 / ha  (£21 / acre).  However was there a cost saving in using the direct drill to establish the wheat crop?  In our small sample of 6 fields the answer is “no”.  It appears that the savings of making only one pass with the drill was largely swallowed up in making two more passes with the sprayer (plus spray) and one more pass with the slug pellet applicator (plus pellets).  The final costing incurred appear almost identical.

Where does this leave the direct drill when establishing wheat?  This Autumn we established all our wheat using the direct drill save one field.

Drilling Wheat in Rape Volunteers 21/9/10

Drilling Wheat in Rape Volunteers 21/9/10 (Left undrilled / Right drilled)

Wheat established by Claydon

The wheat crop on the 11/11/10

It was a kind year to drill this time but it appears the soil OM and structure are changing for the better and should mean the yields improve.  Mistakes such as using low seed rates have been corrected.  In other words, we are confident enough in the system to keep trying.  Any suggestions for the perfect system would be most welcome.

Spring 2010 worm counts comparing a ploughed field with direct drilling

April 23, 2010

Two fields were compared, Hornfield – ploughed and power harrowed, sown to winter wheat, and Cobb Hill – direct drilled to OSR.  Both fields have reddish brown slightly stony silty clay loam soils with coarse prismatic or blocky subsoils.

Worm counts were carried out using the Visual Soil Assessment method (Landcare Research, 2000).  Numbers of worms in a 20cm3 soil sample were counted over a 5 minute period.  Penetrometer readings were taken to assess soil compaction at each sample site and a visual note of soil structure in each soil sample was made.  Five sample sites were tested in each field.

The results below include the penetrometer readings taken in Cobb Hill in October 2009 for comparison.

Average penetrometer readings (MPa)

at depth:

(cm)

Hornfield

April 2010

(Ploughed and power harrowed. Planted with winter wheat)

Cobb Hill

April 2010

(Direct drilled to OSR)

Cobb Hill

October 2009

(Direct drilled to OSR)

5 0.5 1.4 1.4
10 0.6 1.7 2.1
15 0.7 1.7 2.7
20 1.0 1.8 2.8
25 1.4 1.9 3.0
30 1.7 2.3
35 2.1 2.6
40 2.4 2.7
45 2.6 3.0
Average number of worms in 20cm3 soil
12.6

(range 2 – 20)

34.4

(range 29 – 43)

per m3 equivalent 315 860

Notes:

Topsoil structure in Hornfield was coarsley granular but rather wet and easily smeared.  The subsoil became increasingly compacted with depth but had a good blocky structure.  Numbers of worms in each sample were variable, the worms were rather small in size and were found in the upper 20cm of the soil profile.

The soil on Cobb Hill was compacted, especially below 10 cm depth.  The majority of the worms found were in the top 10cm of the soil profile where the soil structure was good, coarse granular.  Below 10 cm depth the soil formed a typical argillic clay enriched B-horizon, generally having a coarse prismatic or blocky structure but with horizontal plates in parts.

General analysis / comment:

There is a clear difference in worm numbers between the two fields, with much higher numbers of worms in the direct drilled field.  This is probably because of the previous year’s crop debris (organic matter) available in Cobb Hill (direct drilled) for the worms to feed on.  Organic matter from the previous year’s crop debris has been ploughed in in Hornfield.  Cultivations carried out in Hornfield will also have disturbed the worm ecosystem, reducing numbers.

Soil structure in the two fields reflects management.  Hornfield (ploughed and harrowed) has a much looser soil structure compared with Cobb Hill (direct drilled) with little compaction until below 30cm depth.  Previous examination of Cobb Hill had already identified the soil compaction in this field, and the apparent easing of the compaction between the October and April readings will be because of the increase in moisture content in the soil after the winter (which allows easier penetration of the penetrometer) and not a reduction in the soil density.

The higher worm population in Cobb Hill will be responsible for the good soil structure in the upper 10cm of the soil profile and their activities will be increasing organic matter content so increasing the moisture and nutrient retaining capacity of the topsoil.  However the compaction lower down the soil profile will be reducing the potential of the crop roots to exploit the full depth of the soil profile.  A point for debate is whether the increased worm population in Cobb Hill and the improvement they will make to the topsoil makes up for the compaction and reduced root exploitation lower down in the soil profile.

Dr. Nancy Oakes conducting a worm count

Soil Structure Update

March 23, 2010

Following the extremely wet harvest and planting in 2007 and 2008 we decided to subsoil (some would say flat lift is a better word) most fields going into wheat or oil seed rape.  This was because the harvesting and planting equipment had caused compaction in the soil structure.  As long as the soil condidions are right when the flat lifting is carried out then the soil should lift and crack, disrupting soil pans and therefore allowing water and root penetration.

Cobb Hill oil seed rape on the 22-9-09 (a month before this test)

However we wanted to see if there was any benefit to the soil structure nearer the soil surface from a pass of the Claydon drill.  Therefore Dr Nancy Oakes and I selected two fields, Cobb Hill and Days Ground which had not been subsoiled.  On the 22nd October 2009 we used a penetrometer to measure the pressure required to push a probe into the ground thus giving an indication of soil compaction.   Cobb Hill had already been planted into oil seed rape resulting in some well established plants.  We tested the pressure inbetweenwhere the drill legs had passed and in the actual seed row.  There is clearly a small reduction in soil compaction in the seed row.  However this result would lead me to mark the field for flat lifting next year.  The results for Days Ground were very encouraging.  The field was being drilled into wheat as we checked for compaction.   The first set of results show a part of the field pre- drilling.  The second set show the exact same spot after the drill had passed by.  There is a notable improvement in soil compaction down to a depth of 25cm.

The full results can be downloaded here.  Penetrometer results October 2009.

Initial Results of Soil Structure Survey

November 8, 2009

As mentioned in a previous blog, the adoption of direct drilling techniques should, in theory, bring about an improvement in soil structure.  Dr. Nancy Oakes suggested the first step to looking at soil structure was to assess the bulk density.  On the 28th September a number of soil cores were taken across the field and the bulk density measured. The bulk density of soil is inversely related to the porosity of the soil. The more pore space in a soil, the lower the value for bulk density and so is a good indication of soil compaction.  Three fields were sampled – Cobb Hill, Lime Street and Roundmoors.  Cobb Hill was drilled in Oil Seed Rape, Limestreet was left as stubble awaiting sowing with winter beans and Roundmoors was drilled into Winter Linseed.  As Dr. Nancy Oakes indicates in her report, the absolute accuracy of the figures is less important than the comparisions between fields and drilled / undrilled areas.  To see the report click here  Hawthorn soils results 1 .  After passing through the field with the Claydon there is normally 7 inches of undisturbed soil between the drill legs hence the measurement of bulk density in the drilled area and between the drilled area.

This is what should happen !

This is what should happen !

Perhaps the most interesting question raised was whether the drill shatters and loosens the soil between the drill rows and so allow  the crop roots to penetrate  and make use of the nutrients or if we just end up with large areas of compacted, relatively underused soil inbetween the drill rows.

directdrill process

Dr Nancy Oakes - soil density

Start of Soil Structure Survey

August 26, 2009

Whilst not the top of the list of topics to talk about in the pub or at the dinner table, soil structure and organic matter content are vital parts of successful arable farm.  For hundreds of years this farm has used the plough to turn over soil prior to establishing a crop and it has proved highly successful.  Ploughing buries crop residue and weed seeds, removes ruts and compaction and releases nitrates which help the new crop to grow.  However with the rise of the price of diesel and steel, ploughing is now quite an expensive option so many farmers have moved to, or experimented with, ‘min-till‘ or ‘no-till‘ techniques.  As I have mentioned in a previous blog we bought a Claydon Direct Drill last year so have exactly one years experience of not ploughing but drilling directly into stubble.  One claimed benefit is that yields should not drop or possibly even increase.

I will post the results at the end of the harvest ! In addition non inversion tillage (not turning soil over) should increase surface organic matter and worm numbers.  Organic Matter levels are hard to measure so I thought it would be easier to monitor worm type and levels.  Dr Nancy Oakes has kindly agreed to do an informal study and visited the combine on August 14th to see how things were going and talk about how to start studying soil structure and worm levels when drilling starts in a few weeks.  We will also compare the results with fields that have been planting after the plough.

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