Just a quicky today, whilst en route from Copenhagen to Legoland. A couple of years ago I went to visit a Danish farmer called Søren Ilsøe, who imports and sells Canadian drill openers made by GEN. Although I was impressed by the hardware I never ended up getting them, but that’s another story.
Søren reckons he is the only farmer in Denmark who is 100% no-till, and now he has moved on to cover cropping as well. Denmark is interesting as they are very politically sensitive to nitrate leaching, and there are a lot of regulations. For a starter, the maximum amount of nitrogen that can be applied to a wheat crop is 138kg/ha – some people in the UK use double this. It is also a mandatory requirement to have a minimum of 10% of the farm in cover crops every winter, or else you lose another 50kg/ha of N off next season’s allowance. The government is also totally prescriptive on what the cover crop can consist of: there are two choices, neither of which I asked Søren about today, but if my memory serves me correctly from 2 years ago, one is ryegrass, the other is a brassica. No legumes are permitted, which seems a bizarre oversight if you are worried about artificial N getting into water supplies.
The first field we walked in to had a border of a legume rich cover crop. It was made up of vetch, phacelia, crimson clover, and one plant that I didn’t know, but looked like a very small leafed vetch. It turns out that it was in fact Serradella – a plant that I had been told about, but found impossible to get hold of in the UK. It is a small seeded legume (good), but according to Søren, quite slow to get going (not so good). I will try to buy some off him to try at home next season.
In the middle of this field were several strips of different cover crop mixes that Søren was experimenting with. The plots were
- Oil radish
- Winter vetch
- Summer vetch
- Black oats & summer vetch
- Oil radish & summer vetch
Spring barley will be going in as the cash crop, and then the yields measured from each individual treatment. It looks an interesting experiment.
The neighbouring field was drilled on August 6th with a mix of oil radish, peas (a small seeded German variety) and vetch. I was complaining to Søren that our cover crops were seriously lacking in nitrogen this year after the wheats yielded so heavily. Given that they use less N than us, and also got good yields, I had expected the same problem here. I think the best indicator of low nitrogen is a brassica: they just don’t seem to grow when it is lacking.I think it is fair to say that’s not a problem here! How can he get plants like this??? It’s a real head scratcher, but there is obviously excellent fertility in the soil.