The Two Simon's Theory

[RBM]

So Clive, if you give up winter OSR you can chop all your straw, rake and grow all spring break crops, or spring barley ? Keeps all the organic matter you produce . We have gone from 2-5% in 10years.Also keeps baler/lorry wheels from doing any damage.

You have managed to increase you om to 5%? That takes some doing I would say!

 

[Feldspar]

So Clive, if you give up winter OSR you can chop all your straw, rake and grow all spring break crops, or spring barley ? Keeps all the organic matter you produce . We have gone from 2-5% in 10years.Also keeps baler/lorry wheels from doing any damage.

What depth do you take your soil samples down to, and has that depth changed at all? TIA.

 

[Feldspar]

@Simon Chiles

I asked on agtalk about this a few weeks back and there was generally scepticism:

http://talk.newagtalk.com/forums/thread-view.asp?tid=472100&DisplayType=flat&setCookie=1

But AMPA seems to be a potential explanation

http://en.wikipedia.org/wiki/Aminomethylphosphonic_acid

I think this is another strand to this debate, and that is to what extent is glyphosate not a contributory factor in this. Have a look back at this thread:

http://thefarmingforum.co.uk/index....sate-may-damage-your-crops.16498/#post-291628

I suppose if you're planting rape into barley straw which wasn't sprayed with glyphosate pre-harvest and you get a poor crop, that would tend to suggest that glyphosate is not the cause.

 

[Feldspar]

Here's some relevant material:

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.1977.tb00672.x/abstract

And even the abstract of this one is very interesting:

http://www.sciencedirect.com/science/article/pii/0038071778900834

Note the recommendation to dust the seeds in powdered chalk. Perhaps a cheaper way than applying prilled lime?

It seems that the mechanism of anaerobic breakdown of wheat straw (and, note, rape straw as well according to the second link) does produce acetic acid which does inhibit the growth of barley seedlings.

 

[Feldspar]

This one too:

http://link.springer.com/article/10.1007/BF02197956

 

[Feldspar]

This is hitting on pretty much the same message as what Simon has said giving the same solution:

http://onlinelibrary.wiley.com/doi/10.1111/1365-3040.ep11581824/abstract

I need to take a trip to the library to get the full versions of all of these. However, it seems from the summary that it may not be the pH of the phenolic acids themselves, but rather that their phytotoxicity increases with lower pH and / or more anaerobic conditions.

So, given this seems to be a pretty well established truth, the question is how to avoid this happening?

It seems that shallow cultivation could work, as could removal of the straw or the avoidance of anaerobic conditions. I would personally like to find a solution that doesn't involve removing the straw because there's not much of a market here, it's a PITA at harvest, not keen on the wheelings, and I want as much residue as I can get.

ETA: http://link.springer.com/article/10.1007/BF00988057#page-1 ... the list goes on.

 

[Clive]

So Clive, if you give up winter OSR you can chop all your straw, rake and grow all spring break crops, or spring barley ? Keeps all the organic matter you produce . We have gone from 2-5% in 10years.Also keeps baler/lorry wheels from doing any damage.

I have all but dropped it, just 5% of my area this year and that's just to give us some early harvest

I think I will be ok growing it after barley with stubble shaved low straw sold, land limed and maybe row cleaners on the drill

Dropping it all together takes diversity and spread of logistics from us plus it does pay better than most alternatives

 

[Luke Cropwalker]

This Winter, because of too much rain and time on our hands, @Simon C and I came up with a theory that we think explains all sorts of things. When we talked about it we found that he had one half of the jigsaw and I the other. Since then I have discussed it with other members of this forum and we are now conviced we might have a theory and also more importantly some solutions. I must also stress that this doesn't just apply to direct drilling.
This is it:-
Any residue of decaying graminaceous material ( sprayed off grass, volunteers or chopped straw from wheat, barley and oats etc. ) are, in anaerobic conditions ( normally wet ), producing considerable amounts of Phytotoxins. These mainly consist of acetic acid but some of the others are butyric and proprionic acids as well. These Phytotoxins are damaging seedling roots and making the plants more succeptible to pathogenic attack ( Fusarium and Phoma ) and, depending on the amount of material and lack of oxygen, can even totally wipe out a crop. Even if the crop survives we think it is affecting plant health and growth and the acidic conditioins are favouring weeds such as blackgrass allowing them to become competition for the crop.
We think these phytotoxins are fairly immobile in the soil; acetic acid concentrations are more than halved 15mm away from the decomposing material. We also think this effect lasts for up to 8 weeks ( depending on temp.) starting from when the material comes in contact with the soil.
Decomposing material from anything leguminous, rape and linseed etc. does not have this effect.

We think this explains several things, one of which is declining yields, especially in rape. We also think that it explains why autocasting can be so hit and miss. If the chopped straw lies in a dry inert layer then your rape will probably be OK, but if the straw turns into a wet soggy matt then production of these phytotoxins will destroy your crop. We also think that often slugs, leatherjackets, wireworms etc are getting the blame for some of these crop failures.
It isn't just small seeds and direct drilling, if you had a lot of grass weeds and you spread beans on the surface and ploughed them in you wouldn't have much of a crop either.
We also think that Strip till is benefitting from having a super row cleaner that sweeps aside the straw to help the situation. However, in severe conditions even this isn't enough.
So going back to our schoolboy chemistry we think the solution to neutralising these acids is lime, and so far we seem to have had excellent results.
Of course you could just wait until all the straw had decomposed, then you wouldn't have the problem anyway.
We also think that the reason that this hasn't become so apparent before is due to the effect only happening in wet conditions and therfore sometimes in drier conditions you can get away with it.
We also think that for cover crops to become successful in the UK we need to think carefully about what to grow and how to destroy them for best effect. For example it would be OK to have barley in your cover if you are going to graze it hard with sheep, but you certainly don't want it in if you are going to dessicate it just before drilling.

It will be interesting to see if the press want to publish our theory or whether they ignore it for fear of upsetting too many advertiserers of machinery and chemical supplies.

If cereal or grass residues produce various acids which may inhibit the growth of cereal seedlings and encourage or at least allow blackgrass to grow. What acids would suppress blackgrass germination and growth and how could we get them onto the field by either mulching a cover crop or through a sprayer, even mixed with a pre-em herbicide.
Luke.

 

[Feldspar]

If cereal or grass residues produce various acids which may inhibit the growth of cereal seedlings and encourage or at least allow blackgrass to grow. What acids would suppress blackgrass germination and growth and how could we get them onto the field by either mulching a cover crop or through a sprayer, even mixed with a pre-em herbicide.
Luke.

Probably the same chemicals compounds that would stop wheat from growing. On the other hand when planting beans maybe this mechanism could be taken advantage of by retaining cereal straw residues, getting the beans below the phytotoxic layer, and preventing black-grass from germinating on the surface.

 

[Hartwig]

What acids would suppress blackgrass germination and growth and how could we get them onto the field by either mulching a cover crop or through a sprayer, even mixed with a pre-em herbicide.
Luke.

Probably the same chemicals compounds that would stop wheat from growing. On the other hand when planting beans maybe this mechanism could be taken advantage of by retaining cereal straw residues, getting the beans below the phytotoxic layer, and preventing black-grass from germinating on the surface.

Certainly the allelopathy effects of Avena Strigosa does what you want. I`ve seen that with great success, growing a weed-free crop of spring beans without any herbicide (well, a late graminicide would be useful maybe) after putting the beans through the solid mat of straw left by the covercrop of Strigosa. Have already thought a lot about extracting this effect and getting it through the sprayer - but unfortunately that is done by root exudates and that biology seems to be burned up with the more tillage that is done, so it`s not very stable and no organism of it`s own.

 

[SilliamWhale]

The plan is to implement some of these ideas this year and then have another of Will's No-Till Alliance open day's here in May '15.

'kin 'ell

 

[warksfarmer]

Just shave the stubble with the header and then remove the straw then !

 

[Fred]

I'm considering the following rotation,

Ww, Sw, Sbns/peaola,ww wosr,

Cover crops after wheat,and between spring crops, a double spring break to confuse black grass,

Direct drill, after, cover crops,

now remove straw in front of osr, and add lime,

And if it all goes wrong , plough, after osr,

Thanks guys the jobs sorted, now just got world peace to sort out

 

[rob1]

Probably the same chemicals compounds that would stop wheat from growing. On the other hand when planting beans maybe this mechanism could be taken advantage of by retaining cereal straw residues, getting the beans below the phytotoxic layer, and preventing black-grass from germinating on the surface.

First bit of dd I did was with a simtech, wheat into chopped wheat straw, was a good crop and very little bg in what is a bad field for it, second was osr into the chopped wheat straw, thought the slugs had had it but perhaps as the osr was not drilled very deep it was this effect that made it fail, interesting theory. I wonder if following a crop with another of the same species would have the same effect on the planted seed as on a seed whether drilled or weed of another species

 

[Clive]

it certainly explains a lot of WOSR failures in 2012 with very anaerobic conditions. WOSR must be the UK's most DD'ed crop with many using subcast etc as well as strip til and zero-til

the wet harvest would have ment that very little straw was removed as people tried to avoid carting damage and trying to turn ground around fast as date got late

 

[yellow belly]

when I was at college I did a project on straw incorporation burning was still allowed but controversial

in the 1970s (not sure where Letchworth rings a bell) there was some research done on straw in the soil the conclusions were that straw ploughed down or incorporated was bad for crops and so removal or burning was the only option but in the 80s some farmers were mixing straw in the soil Peter Hepworth was one

 

[Fred]

This might answer a few questions

 

[yellow belly]

for winter osr
should we be leaving the straw long as finely chopped it leaves a layer close to the soil when it falls through the stubble

or bale then return as compost or fym

for spring beans leaving a layer drill through with a disc drill ,the layer then reduces weed growth did in 2013 crops


in 2011 spring beans no straw problem as dry spring

2014 now dry but straw baled

for 2015 will combine as long as possible then bale
balers run the same wheeling as the combine 9m apart running on under 20%

or just hope we have a few dry years compared to the last decade more like the 1980s
when we had 8 dry 2 wet !

 

[Dockers]

Feldspar, about 25cm. Same depth for the last 10years. Same sampler. ( Mike Harrington, Edaphos )

 

[Cab-over Pete]

If cereal or grass residues produce various acids which may inhibit the growth of cereal seedlings and encourage or at least allow blackgrass to grow. What acids would suppress blackgrass germination and growth and how could we get them onto the field by either mulching a cover crop or through a sprayer, even mixed with a pre-em herbicide.
Luke.

If you have a look on normanandspicer.co.uk you will see that Mark Spicer has been doing some work with high glucosinilate mustards. They are grown over late summer, flail topped and immediately ploughed in. I see Mark occasionally and the photos he has seem to show incredible results.

Re using FYM instead of leaving chopped straw and how it doesn't seem to cause the localised acid problem, I can't recall a mixed farmer telling me they have the problems found by 100% arable farmers. They may have some of the problems, but not to the same extent. I have often stated on here that some of my best wheat growing customers are mixed farmers. To a man, they are fussy about their pH.

They are most likely fussy about everything else too- I'm not suggesting it's just the lime putting everything right, but certainly a higher than necessary pH is doing them no harm. I have grass growers that want pH values up at 7 too, and they can grow some serious grass, I can tell you.

I know you chaps aren't necessarily talking of using lime to raise pH throughout the whole of the topsoil profile, but if you keep your pH at a good level over the years as a matter of course, surely you are readying yourself in times of wet and anaerobic conditions.

But then I would say that wouldn't I ?!

Is there anyone here who has heavy calcareous clays with a naturally high pH but still has the problems described here in DD situations?