Cover Crops: Validity / Grazing Issues?

[Robert]

We have planted over wintered cover crops for the last 2 winters, followed by spring oats and linseed. Have seen really pleasing biomass produced and have mainly grazed this off with sheep. i think the whole concept of maintaining growing crops for the soil biology to interact with, soil moisture management, soil structuring via rooting etc quite logical / convincing but some results this season suggest that careful management of grazing to avoid surface compaction / tilth loss is very important to the extent that if you breach a certain level of over grazing as we seem to have done this year, i think we'd have been better off just leaving the stubble over winter.

We have some excellent looking S Oats on land intended for winter wheat which we consequently didn't drill a cover crop on after harvest. The Oats follow linseed admitedly so it should be a very kind environment - and they are thriving. S Oats after grazed cover crop after wheat are a fair bit thinner mainly due to poorer establishment brought about by poor tilth creation and therefore seed to soil contact. I am fairly happy that the grazing compaction is very much in the surface so i believe the pooer growth is due to a poorer start rather than general impediment as the roots have got going. We have spring barley after s oats where it was left as pure stubble and they have got away nicely.

I think that all in all it perhaps highlights the extra management required in the process and having to consider things on a field by field basis. Not having direct control of the sheep doesn't help, and every season is different: amount of wet, amount of frost heave before drilling etc...

We really need to do more trial work on this to get an idea of effect on yield. The crop growth results we're seeing this year though just pose the question of overall - are the cover crops really necessary. The Wheat / Fallow brigade often seem to manage well without so why hasn't their soil biology suffered? Dockers??! Perhaps one extreme or the other is sensible - i get the impression that constant max cover (no grazing) has real merit.

p.s. Drill = Claydon Hybrid

 

[Clive]

Personally I think fallow is a soil disaster

It makes no sense to me to deprive soil of all food and waste the chance to convert several months of sunlight and water into carbon ?

I can see that grazing covers can have potential for problems - do you think a shallow surface cultivation would have sorted the issues you have seen ?

Are you grazing to make the drill work ? Would you not graze cover if you had a disc drill that could cope with any amount of biomass ?

 

[JNG]

Quick question Robert, have you tried to drill into any covers with the Claydon that have not been grazed? I am planning to establish some crops after winter barley so should get away well. I also have fears about sheep and poaching if a wet winter etc, and you cant either buy or commit to take someone else sheep and then decide its too wet to graze. But Im concerned about how to handle these covers next spring, dont know will I need to mulch with topper (damp soils early spring I dont want to drive on), or run with carrier or the like which is not the point of DD really. I know the answer is I need a disc drill but I am not ready yet!!!

 

[Dockers]

Robert/Clive. I love the idea of cover crops. 10 years ago we had a real good go at it, for 3 years ! Tried all the combinations that you are trying ( except pedders mix ) Found no benifit/ cost return on OUR soils . ( different types, all over chalk ). Still trying to find a crop to grow between 1st wheats that is worth the effort. Always end up doing twice the work for the same money.
!2 years now of mainly wheat/fallow on 2000+ Ha. Profitable, Enjoyable, Sustainable.
Have grown our bussiness by being different, but it is not everybodies choice!!

 

[SilliamWhale]

I think this year, being the coldest since 1962 is quite probably not cover crops year. Another year may be different. I don't actually think it is a disc Drills' spring particularly but another year could be different.

 

[York]

Robert/Clive. I love the idea of cover crops. 10 years ago we had a real good go at it, for 3 years ! Tried all the combinations that you are trying ( except pedders mix ) Found no benifit/ cost return on OUR soils . ( different types, all over chalk ). Still trying to find a crop to grow between 1st wheats that is worth the effort. Always end up doing twice the work for the same money.
!2 years now of mainly wheat/fallow on 2000+ Ha. Profitable, Enjoyable, Sustainable.
Have grown our bussiness by being different, but it is not everybodies choice!!

sorry, sustainability is a too big word and will be vindicated or not over TIME!
Please read the book "Dirt" and there the part of the history of Spain & Italy under the Romans. They did this as well....
also look at studies in the Pacific Northwest, Washington state on Fallow. Or Canada, Saskatchevan etc.. Even Russia is now learning that a rotation of 1 year wheat & 1 year fallow is not the best to do.
Point is that it takes quite some time to change a soil, in both directions. Even soil erosion of 2 mm / annually are not seen. As it's bugger all.
York-Th.

 

[Dan Powell]

Going back to the sheep issue, we saw the same thing this time on a DD'd Pedders mix. Sheep grazed down to 50 mm and then removed. This is on a 9 hectare sandy loam field after winter barley. Was going to DD maize, but the surface was like concrete in the spring. About 80 mm of compaction and then lovely structure underneath so we min-tilled.

Lesson learnt: compaction is a function of time. Do not set stock the sheep. Strip graze where possible (daily moves) with a back fence and trample some of the cover to feed the soil. Finding a sheep man that will do it may be tricky.

 

[Robert]

Quick question Robert, have you tried to drill into any covers with the Claydon that have not been grazed? I am planning to establish some crops after winter barley so should get away well. I also have fears about sheep and poaching if a wet winter etc, and you cant either buy or commit to take someone else sheep and then decide its too wet to graze. But Im concerned about how to handle these covers next spring, dont know will I need to mulch with topper (damp soils early spring I dont want to drive on), or run with carrier or the like which is not the point of DD really. I know the answer is I need a disc drill but I am not ready yet!!!

Hi JNG, yes we graze to suit drill and because it seems the best of both worlds - rooting benefits remain intact (eg some lovely turnip tap roots), and the above ground biomass is recycled into fertiliser as our learned friend Frederick Thomas would say. Did try some direct into the intact cover last year, and it was a bit "clumpy" where it gathered up but grew ok. Think Mzuri with leading cutting disc would fair better. Also experimenting with old 750a though not been too radical as yet - must do more trials.

Going back to the sheep issue, we saw the same thing this time on a DD'd Pedders mix. Sheep grazed down to 50 mm and then removed. This is on a 9 hectare sandy loam field after winter barley. Was going to DD maize, but the surface was like concrete in the spring. About 80 mm of compaction and then lovely structure underneath so we min-tilled.

Lesson learnt: compaction is a function of time. Do not set stock the sheep. Strip graze where possible (daily moves) with a back fence and trample some of the cover to feed the soil. Finding a sheep man that will do it may be tricky.

Agreed - sheep man needs to have an understanding of bigger picture or you have to be looking over his shoulder constantly which is tedious / knocks viability.

 

[neilo]

Agreed - sheep man needs to have an understanding of bigger picture or you have to be looking over his shoulder constantly which is tedious / knocks viability.

Would the 'sheep man' that you get to do daily moves & back fencing, not want to pay a lot less for the keep? That's assuming you can find one, local enough to be able to p*ss about every day, and willing to undertake the job.

I know the DD purists will hate the idea, but is there a place for taking more from that sheep man, who may (in a winter like we've just had) cause a little surface compaction, but which can be quickly/simply/cheaply remedied with shallow cultivation? In return, you get 90% of that cover crop turned into a useful slow release fertiliser (sh1t), less bulky residue to try and drill through, lower slug pressure and a useful income.

 

[Dan Powell]

Would the 'sheep man' that you get to do daily moves & back fencing, not want to pay a lot less for the keep? That's assuming you can find one, local enough to be able to p*ss about every day, and willing to undertake the job.

I know the DD purists will hate the idea, but is there a place for taking more from that sheep man, who may (in a winter like we've just had) cause a little surface compaction, but which can be quickly/simply/cheaply remedied with shallow cultivation? In return, you get 90% of that cover crop turned into a useful slow release fertiliser (sh1t), less bulky residue to try and drill through, lower slug pressure and a useful income.

Indeed, although by strip grazing utilization would be a lot better as the sheep won't spend so much time wandering about looking for the ultimate turnip and will have a more balanced diet too rather than eating all the rich pickings first.

 

[Baling Hay]

Indeed, although by strip grazing utilization would be a lot better as the sheep won't spend so much time wandering about looking for the ultimate turnip and will have a more balanced diet too rather than eating all the rich pickings first.

I don't think strip grazing will help that much. Granted they won't be walking about as much but at wet periods they will badly affect the condensed area they are in at that time.

 

[BSH]

I have found that areas that I thought were well poached by the cattle in a field of forage rape. grazed in nov/dec drilled no problem in april. I would think any mess made by sheep would be insignificant.

 

[britt]

My experience with S linseed over the past 3 years, has been that emergence has been better and faster where the ground (wheat stubble) has been bear over winter and poorer where there have been a lot of volunteers (no cover crop planted). This year there has been slug damage where the wheat or grass has sheltered them.
A effect that I have noticed is that the roots bind the soil together between where it has been cut by the disc, then as the soil dries the slot opens up.
If you are going to grow a cover crop perhaps you need to cultivate it into the surface, as we saw at the BASE meeting. This would solve many of the problems and put all of the OM into the soil.
Areas spayed off in the autumn due to high grass populations also do better than areas left to green up.

 

[JNG]

Ok so what Ive learnt here, (I have 100+ acres of Pedders 3 + pedders French mix ordered)
1. Grazing could work well but problems may occur, especially if wet (I think ill avoid or maybe just a light grazing)
2. Destroy early to let everything die properly.
3. If in doubt cultivate in to incorporate residue and prevent drill blocking.

 

[britt]

I should add to the above that we are on medium to heavy land.
If you are on light land the benefit of the cover crop would be much greater and the soil behaviour very different.

 

[JNG]

Not always that easy on light land either, this is after cover crop of westerwold ryegrass (after winter barley)grazed by sheep all winter, there is a tight area between 1 and 3 inch depth(cultivation zone for past few years). I think it is more to do with rainfall and tightening in a sand/silt loam but grazing (trampling) probably did not help. There was a rotten smell to that area of soil, top inch very good and below very loose That said Claydon drilled peas direct into above looking well at the moment. Grazing of cover crops like soil traffic will be easier once a better structure in place to hold it, dont think Im quite there on this field yet!

 

[Baling Hay]

Maybe in the UK with our high rainfall grazing is not a good idea for arable men due to this compaction? It is different in USA with their drier climates and hard frosts which helps to break it up anyway.

 

[JNG]

Maybe in the UK with our high rainfall grazing is not a good idea for arable men due to this compaction? It is different in USA with their drier climates and hard frosts which helps to break it up anyway.

I agree a hard frost would have helped crack up this layer its very near the surface. Grazing I think would be fine if you get a forcast for a few wet days you could take the stock off till it dried up again but not always possible, especially if you have promised grazing to another farmer.

 

[Baling Hay]

I agree a hard frost would have helped crack up this layer its very near the surface. Grazing I think would be fine if you get a forcast for a few wet days you could take the stock off till it dried up again but not always possible, especially if you have promised grazing to another farmer.

The other thing to remember that by grazing cover crops you are actually removing nutrients from the field. Think of the energy lost due to respiration by the animal and then the carcass leaves the field.

 

[JNG]

The other thing to remember that by grazing cover crops you are actually removing nutrients from the field. Think of the energy lost due to respiration by the animal and then the carcass leaves the field.

Yea but we have to sell something? Thats our business! I get your point tho if the cover crops are for the purpose of soil building etc. I like the idea of something paying for the seed/establishment and it being cost neutral, and they do leave some nice readily available fert behind.. There is pros and cons to the whole thing.