Many hop farmers in the UK feel unsatisfied by the lack of government investment in research and development into hop agriculture. So, a group of hop farmers took research into their own hands. They investigated the benefits of growing cover crops in the fallow season after the hops have been harvested. A practice which is especially important as the entire hops plant is removed from the field in harvest so organic matter is not returned to the soil as part of a normal cropping cycle.
One of the participants in this field lab is Ross Hukins, a fifth-generation specialist hop grower who farms on 50 acres in Kent. We asked him about his experiences of farmer-led research.
Ross: We’ve always kept our soils bare and open all year round. The main reason for this is verticillium wilt, an old disease, that has been responsible for wiping out hundreds of hop farms in the UK. As a hop farmer we have to be very careful what plants we introduce into a field. Added to this our land is clay, so on our soils the hops yields are pretty stunted because of the harsh nature of soil. They often sit wet in the winter and start rotting. And in the summer, they bake out and can’t get access to the nutrients they need. So improving soil fertility and organics in the soil could be hugely beneficial.
We can’t grow anything beneath the hops in the growing season because they can’t handle the competition; So the idea was - why can’t we put something in during the off-season to maintain soil stability, prevent erosion, maintain and improve fertility?!
We wanted something that could capture as much of the excess nitrogen fertiliser as possible. We also wanted to introduce some biomass to give the land plant material to drive the tractor on in winter and avoid unnecessary compaction.
Cover cropping is an old idea in farming, but it’s a good idea. Farmers have moved away from it because it’s another cost and another thing to do, and the hops market was supressed. But we’re specialists, the hops market is better, and that’s why we were looking for ideas for trying to improve.
Ross: We chose black oats for our cover crop. This is because it is a hardy crop that would grow in the clay. And we can’t use broadleaved plants like legumes because they can carry wilt which could spread disease in the farm. So last year we broadcast it just after harvest and rolled it. It grew very well where we put it in. We tried different seed rates and discovered that it needed a higher rate of 75kg per ha. The higher the better on our soil to get a better establishment, however we had to balance that against seed cost. We let it grow all the way through the winter and just before the hops came through we put glyphosate on it to ensure it was dead, and we just let it fall over naturally. Now it’s mulching down and in a few weeks it will decompose into the soil.
Ross: From our perspective the cover crops have been a great success. It’s difficult to measure the impact on yield but we’ve already seen lots of benefits. All the hops are grown on banks because they like free-draining conditions, particularly on clay because it sits wet. We have a garden where we’ve also got a steep bank and, in the winter, it’s almost a river and you can see the erosion from heavy rain taking place and the top soil being washed away. That’s not happening where we’ve put the cover crop in.
Other benefits include being able to run on the soil earlier in the year because there’s something for the tractor to drive on. And we can see the mulch rotting down so that’s got to be a benefit to the soil fertility. This year we did 5-7 acres (roughly 10% of the farm), and this summer we intend to do the whole farm apart from tiny areas where we’ve got wilt and don’t want to disturb the soil.
Ross: We need to improve our yield over the long term and understand and develop practices to support this. So far, we’re doing that ourselves because there’s very little R&D in hops anymore.
If you go to Germany where hops are seen as an absolutely crucial part of agronomy, hop growers have huge resources, allocations, grants and research budgets from the German equivalent of Defra.
That isn’t the case here. So, if we want to improve our industry we’ve got to do it ourselves.
If we get striking results with the Innovative Farmers trial with cover cropping, we will disseminate all that information out to all the growers so they can have a think about having a go themselves.
Ross: The hardest thing was just getting hold of the black oats at cheap price. Finding people growing them was the biggest challenge. With the broadcasting equipment, one grower used his own applicator and he threw it everywhere and then he got the cover crop growing in all the wrong places which caused big problems. So broadcasting isn’t the best way to plant. Drilling is better. Initially the little broadcaster that we bought with the money from Innovative Farmers did work, but I think long-term, direct drill will get a better and more controlled result.
To keep informed of how this field lab and others are progressing sign up and become a member of the Innovative Farmers network. Got your own idea for a field lab? Then contact the team to find out how to get involved.