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.