Inter-Cropping Insight

Inter-cropping Sprayed Off

Back when we planted the oilseed rape crops in August we also planted their companion crops. This year we used 10Kg of vetch and 2kg of  Berseem clover/per hectare. These companions have grown very successfully through the autumn and into the winter. During the winter we sprayed a weed killer on most of the crop to remove the companion crops as well as weeds like sow thistle, mayweed, brome and black-grass. This herbicide does not affect the oilseed rape crop. Both of these legume crops are able to host soil bacteria to make plant available nitrogen from the atmosphere, something that the oilseed rape crop in unable to do. We hope that as much as 30-50Kg/ha of nitrogen will be available free of charge from these companion crops, easily covering the initial cost of the seed. This could be worth between £25-£41/Ha.

Canopy of Sprayed Off Inter-cropping

The picture above shows the crop where the companion crop has been sprayed off. We can measure the GAi (Green Area Index) or amount of green plant material with an app on a mobile phone. This picture shows a GAi of 1.34. There is about 50Kg/Ha of nitrogen in every GAi of an oilseed rape crop. Therefore this crop has captured 67Kg of Nitrogen. The picture below, where the companion hasn't been sprayed off, has a GAi of 3.05 indicating a potential level of 152Kg/ha of nitrogen in this whole canopy. Whether all of this canopy will relate to available nutrients for the oilseed crop to capture is something we don't know but its very interesting to see these levels of free nitrogen, even accounting for the 25Kg of fertiliser applied at planting.

Canopy Of Inter-cropping

We are planning to leave this area of the field until harvest to see what effect it has on the overall yield of the combined species. We should be able to reduce the amount of nitrogen this part of the field receives in order to keep the crop standing but also to rely on the nitrogen being created by the vetches and passed over to the oilseed rape. Time will tell what the outcome will be!

Grazing Ewes on Cover Crops

Ewes Grazing Cover Crops

Well the rams have really been doing their stuff in the last 4 weeks with almost all of the ewes now hopefully pregnant.  In the first week over 600 ewes were mated, as indicated by the chalk dye that the rams leave of the rumps of the ewes during mating.  The colour is changed every week so we have an idea of which ewes are likely to be lambing and when. The gestation period is about 5 months so we're on for a mid April lambing, which next year will be outside for the majority of the flock for the first time.

At the moment all of the ewes are out grazing the cover crops on the arable fields.  The cover crops are a mixture of forage rye and vetch or black oats and vetch with a few extra goodies thrown in for good measure.  These extras include phacelia, buckwheat and berseem clover.

The hard spell of weather recently, although it didn't last very long, has certainly knocked the cover crops down but it hasn't killed them and we are getting some regrowth on the rye fields.  This will hopefully continue over the winter and into the spring to enable another grazing before the ewes lamb and the fields are planted with spring cropping. The field below is due to be planted with Soya Beans in late April so we should get a second grazing before then.

Cover Crop After Ewe Grazing

The ewes are doing a great job of eating the majority of the green material. But it's not just the cover crops, volunteer wheat and some black grass as well, whilst trampling some of the material into the soil to feed the microbes and worms. This is a great news as the field/soil surface looks well protected from the heavy winter rainfall that we must surely get at some point.  We'll have to watch it on the heavy land fields so that we don't get too much surface compaction if it gets too wet, but we are not there yet.  The soil has restructured itself  beautifully on the clay soil part of the farm enough to carry stock, but it has taken 3-5 years of no till to reach this point. There is still a long way to go until the spring so we'll have to see how things progress.

Crimper Conundrum

There is so much public awareness of the perceived issues with Glyphostate at the moment even though 3300 studies have shown it to be a very benign chemical when used correctly in the field.  With any potential restriction on its use being enforced on us I wanted to have a look at an alternative method of killing a cover crop before we plant our harvestable, or cash crop, into the field.  To me a cover crop can only enhance the soil and the wider environment.  It shields the soil from rain, reducing runoff and erosion; it feeds the soil biology with carbohydrates and encourages the development of below ground microbial populations; provides winter feed for our sheep; increases soil organic matter to hold more nutrients and water-its a no brainier for the farm and the wider environment.

Black Oat and Vetch Covercrop

Without glyphosate the termination, or killing, of these crops could prove to be very tricky in our maritime climate.  The cover crop can grow rather large and I don't want to have endless passes with toppers or cultivators to kill the cover crops.  Doing this is expensive, uses fossil fuel and releases CO2, cultivations mean even more CO2 released from the organic matter held in the soil, as it is exposed to oxygen, it means more tractors on the land, causing compaction where they drive which can lead to poorer water infiltration and therefore soil erosion.  So what's an alternative?

With a loan of a crimper roller from Cotswold Grass Seeds (thank you) we had a little play in a large cover crop of black oats, vetch, phacelia and berceem clover.

The idea of the crimper roller is to lay the plants down and squash the stems with metal blades in the hope that this bends or cuts the stems stopping nutrients getting up the stem into the top of the plants, end result being the killing of the cover crop, and any nests or wildlife that gets in the way-but we'll gloss over that for now!

Crimper Roller

We tried the crimper roller on the back of a tractor at first and drove in reverse to make the chevrons point in the right direction but ended up going in round in circles!  So we unhitched the weights from the front linkage of another tractor and set off across the field at 10kph, with the crimper on the front with a bit more success!  The roller weighed in at 620Kg for a 2m machine so about 310kg/m.

Crimped Covercrop 7 Days Post Crimping

I came back to the plot 7 days later to see if it had actually worked and I am sorry to say that it didn't. The oats seems to still be alive and the vetch, which I though would have been totally animated, were still just about hanging on.  The concern for me is we need to find something that works consistently every year and as every season if different.  We need to grow significant levels amounts of green matter and these need killing-somehow.

Maybe we used the wrong machine, maybe at the wrong time  for the plants growth stage,or at the wrong speed or it wasn't heavy enough?  Maybe we need to graze some of the covers down first to weaken then plants?  Maybe it just doesn't work in our climate where we don't always have a frost to follow up and finish off the wounded crop?  Who knows and more work needs to be done, but for now I am not impressed.

Great Companions

Great Companions,

For the last 3 years we have been experimenting with companion crops in our oilseed rape fields.  The companions are mainly based around legumes to try and increase the amount of atmospheric nitrogen that we can capture and then make available to our farming system, and why wouldn’t we?  The atmosphere is 76% nitrogen and yet our cereal and brassica plants cannot use any of it.  But legumes can-and they do it very quickly.

For the first time we have been using berseem clover and vetches together, all planted at the same time as the oilseed around the middle of August.  It has amazed me how quickly the seeds geminated and the speed at which they have continued to grow.

Almost immediately the plants germinated in the no-till soil, where the surface hadn’t dried out and the vetch was soon putting a decent tap root down in to the soil.  This I think has helped the oilseed rape, slightly slower to germinate, by starting to create routes down through the soil in search of nutrients and water.

After 6 weeks I dug up some of the vetch plants to reveal that they had already started to nodulate and the bacteria has started to convert nitrogen from the atmosphere into a plant available form.  This works really well when the soil is aerated, (soil needs oxygen) there is a host and the right bacteria are present in the soil.

The oilseed rape plants look healthy, the weeds have virtually all been competed out and with no broad leaf weed herbicide,

due to the canopy development and we are producing nitrogen for free.  We will see how the companions develop over the winter before they are all terminated, releasing their stash of nitrogen for the oilseed rape plants to use next spring and summer.