Cover crops for cash?
By Georgie Cossins
Cover crops have occupied much of the agricultural limelight over the past couple of years. Some farmers have embraced them while others believe them to be just a passing fad. Their increased popularity today might perhaps be down to the CAP Greening rules; or perhaps they have a genuine importance in improving soil health. As a Monitor Farm, we decided to discuss this issue in our December meeting.
I should preface my comments by saying that on our farm we have always grown cover crops for out-wintering our young-stock cattle, and so this is not an entirely new idea for us. However we have always considered cover crops a resourceful feedstuff for our livestock, and the fact that they are beneficial for our soils has always been a bonus rather than the primary incentive for growing them. There is a cost to growing the seed, as well as additional costs to establishing the next crop, so a cover crop needs to be worth growing. We plant our out-wintering crops on land that does not have oilseed rape in its rotation so clubroot has never been a concern for us.
We had Tim Stephens from Wessex Water and Paul Brown from Kings Crops come and speak to us about why they felt we should be growing cover crops. Tim Stephens illustrated how oil radish in particular was a fantastic crop for reducing nitrate leaching into our rivers and watercourses, and then Paul Brown explained to us how nutrients captured by the cover crop were going to help increase soil fertility and crop yield in the future.
We are located on the chalky downlands of Dorset and so our soils are prone to heavy leaching. There is no doubt that we have a moral duty to help protect the quality of our water, but in doing so are we really going to reap financial rewards? The room was very much divided on this latter point. Some felt that the effects on soil health would be cost effective in the long term; others that these crops were never going to be more efficient than purchased fertiliser.
And then came the issue of the practicality of establishing and destroying these crops. As we all know, if a cover crop is sown late then the crop will not reach its potential and may not even establish at all. The crop must be sown during our harvest season on the farm, along with our oilseeds, grass seed and feed grown for out-wintering cattle. So can we even afford the time or contractor fees required to grow these crops? And if we grow oil radish then are we creating clubroot problems for our oilseed rape?
I think it is fair to say that both Dad and I are not entirely sold on the idea of cover crops for cash benefits. The increased yield of a subsequent crop in a healthier soil may not sufficiently compensate for the cost of growing the cover crop and preparing the seed-bed afterwards. We do think they are worthwhile in the protection of our environment; however they are not a silver bullet to solve all environmental needs, and they should be used in tandem with a whole range of measures, such as having a longer crop rotation, growing grass leys and spreading organic manures, to ensure healthy, fertile soils.
The topic for our next Monitor Farm meeting in February is fungicides. (register to attend)