Rotationally ploughing in a DD system is bonkers?

[Feldspar]

I hear of several people who have a predominantly DD system with the exception that they like to plough every once in a while. Elmstead I think was a proponent of this system. I can see the intuitive attractions - being able to bury troublesome weed burdens and loosen compaction that might have occured over the previous few years - and the reasons why it would be necessary, for example if root crops enter the rotation. That might be true but what I question is whether one can really hope for the benefits of direct drilling if ploughing occurs every 5 years for example.

From what I've read the evidence suggests that if you plough you undo a lot of what you will have gained from the previous years of direct drilling, you will return to Go and you will not collect £200 etc. It will then take 4 years or so to get back to where you were before you lasted ploughed whereupon you plough again and the cycle repeats.

Here's a taster of what I've read, there are more which reach the same conclusion:

https://www.soils.org/publications/sssa ... 0580061782

Do you agree?

 

[SilliamWhale]

It depends.

if your rotation in the USA was continuous corn and the top is all lignified and not breaking down because of the excess of C in the GM crops then ploughing would release nutrients. If you balance out your rotation and think more systematically then No Till is easier to manage.

But I don't find ploughing vs DD studies particularly useful any more than I would telling me it takes longer to get to Germany by train than it does by air. I think the HGCA is doing one at the moment and it will be a waste of money.

Some people (my Dad for example) still see ploughing as the way to do things properly even after 6 years of good DD crops. The perception of the "correctness" of ploughing is deeply ingrained not least because of tradition but when I try to look at it as rationally as possible I can't find myself agreeing - it usually is to cover up previous management problems (rutting, compaction etc, poor rotation) or it is a mining process in itself, for me the case that ploughing and increased UK arable acreages have led to soil OM decline is inarguable, but how much of a problem is it really as we still have plenty of cheap inputs and subsidy to negate this.

 

[155tm]

Our rotation has been WW, OSR, Spring Beans, WW. Ploughing for beans, shakerator mounted seeder for OSR and shallow till for WW. our Organic Matter content this summer was around 4% but we have been using compost, paper waste, muck etc.

Couldn't seem to get to the next level, it felt as Will says that we keep going back to the beginning each time we ploughed. Still got blackgrass and yields were no longer climbing. Time to think again.

The WW is nearly dd already. The shallow till had been to get a stale seedbed, are these right? Burying the blackgrass so it can germinate from differing depths, at differing times. The deeper, later, possibly after the glyphosate application plants will have a stronger root system and be harder for in crop herbicides to kill.

So here we are, I agree with you Feldspar and Will, the next stage must be continuous DD rather than opportunistic DD. Once you make that decision how to help DD succeed is the question? Cover crops to maintain a protective cover on the soil, companion cropping, low disturbance seeding, and is controlling traffic over the soil necessary? At this stage we are controlling it because we can, and it might be necessary?!

Disadvantages are going into the unknown, slower nutrient cycling it is still in the field and in theory less is lost to oxidisation or leaching but not cycled as quickly back to the crop.

What is more difficult to do is move away from that Horsch duett coulter, it could be a good tool to mineralise a little more N than a disc in the interim years but does disturb much more soil and cause more weeds to germinate than the disc.