Cover Crop Benefits

Catchment Sensitive Farmers Meeting

I had a really fascinating day in Dorset today, exploring the use of cover crops to capture nutrients, (mainly nitrates) and stop them being washed through the soil profile and into ground water. The day was organised by Wessex Water and the Catchment Sensitive Farming organisation. Fellow Nuffield Scholar Tim Stephens and his team have put together a matrix of different cover crop species and seeding rates to look at establishment, nutrient capture and suitability within the field. The catchment also has porous dotted around the fields and every 2 weeks from October to the end of January samples are taken and the levels of nitrate in the water assessed. These values are then turned in to a Kg/Ha of nitrogen to give farmers a vital guide as to where leaching is occurring in the farming rotation and how much is being lost and when leaching occurs.

It seems that the worst leaching occurs after Oilseed Rape and Wheat, probably due to the higher levels of fertiliser they receive but also due to the very inefficient way these plants use the applied nitrogen. Wheat for example is only about 60% efficient when looking at applied or synthetic nitrogen fertiliser. Where cover crops are used the leached level of nitrogen is about 50% that of land farmed without cover crops. This has a significant impact when looking at the catchment as a whole. It is great credit to Wessex Water that they have decided to take this partnership approach to try and reduce diffuse pollution working together with the farmers in the catchment.

Beneficial and Pest Numbers in the Cover Crops

Also on hand were a team of entomologists who have been assessing the impact of cover crops on the insect population. The picture above shows the numbers of insects trapped over a 7 day period. The 2 trays on the left show the beneficial's and on the right are the pests. The top half shows the numbers and type captured in the cover crop field (oil radish and phacelia) and the bottom half shows what was captured from a control field i.e. no cover crop. This level of detail is very encouraging. This clearly demonstrates that cover crops are hosting higher insect levels all round but significantly more beneficial insects that will predate the pests. This is so important when looking at using an Integrated Farm Management approach to try and reduce the amount of pesticides we might want or need to use. There were lots of carabid beetles, who's larvae predate slugs which is also very positive. The benefits weren't just in this cover crop species mix. the photo below shows what was captured within a buckwheat, oil radish and phacelia mix. The predator list includes, carabid beetles, springtails, harvestman spiders (not really spiders at all), ants, spiders, and parasitic wasps. The pest list includes mites, flies, aphids, snails and a slug.

Beneficial Insects and Pests trapped from Cover Crops

The session continued in the local village hall with a great presentation on 'Making the Most of Cover Crops' by Ian from Oakbank. Ian talked about different cover crop mixes, how and when to establish them, and the merits of diverse mixes and the impact of this type of farming can have to the on the bottom line and the better environment. A great day of learning.

"To Spray or Not to Spray?"-That is the Question

We have just completed the Health and Harmony consultation organised by Secretary of State for DEFRA Michael Gove where we were asked to put forward our views about the new Agricultural system post Brexit. There was a lot of noise and gesturing from many sides of the argument about what our country side should and must produce. Very sadly the words 'Food Production' were missing from the initial phases of the conversation and ultimately this is only part of the argument. Our ever shrinking and ever compromised countryside has and can produce a wide range of 'public goods' It can provide, food, environmental benefits, jobs, clean air and water, it can provide habitat and food not just for people but also for our wildlife, but it needs a balanced approach.
Lets also be clear that between 2006-2012, 224,200 Ha was developed in the UK (Professor Heiko Balzter-Leicester Uni) for infrastructure, roads, rail, houses, golf courses and wind turbine's. This squeezes the natural world into smaller and smaller segments. More people in the countryside, more disturbance means less wildlife. This was observed in the 2001 Foot and Mouth outbreak when public rights of way were closed during the breeding season and farmland bird numbers rose.
This blog isn't a piece about how we should be supporting farmers to produce food.  It is about supporting farmers to provide what many are already doing-a balance of environmental resilience, economic return and healthier foods. But this way of farming does not come without its risks and sometime for no reward and this Michael Gove, if you are reading this, is where farmers who are doing the right things need support. Let me give you a scenario.

We are a notill farm cropping arable crops and this spring has been the wettest and coldest for a long time, but this farming that's in our bloody, we know the risks. One of the challenges we have set ourselves as LEAF farmers is to reduce our impact on the environment and I have set a challenge to not use insecticides on the farm. The theory being that natural predators will increase with the habitat we have created and help us control pests when they appear. Great in theory but here is a dilemma in some spring sown Linseed.

Linseed with Flax Beetle Damage- Photo from David Miller

The notches you can see are being caused by the flax beetle, (one visible top half toward the right) of which there is no seed dressing to control (not a neonicotinoid solution in this case). We use an economic threshold of 3 beetles in a 5cm row of crop to assess the economic return to make the case for spraying field wide insecticide. Out of stubbornness; I don't want to use insecticides, I try to turn a blind eye to this economic threshold, and environmentally we want to do the right thing. If we don't spray then the plant population could be reduced by 50% and the seed yield at the end of the day will be less than half. This is because fewer plants will be less competitive to weeds, loose vigour and so yield suffers a disproportional reduction. Linseed is worth £375/tonne and has a target yield of 2.25t/Ha, meaning this field (7.5ha) could loose over £3,500 in income (1.25t/Ha @£375/tonne), for a treatment and application cost of £75. (whole field). The economic argument is obviously very clear if you were Mr Hammond sitting in the treasury Dept the decision would be very easy. Are there some alternatives to spraying?
We as a LEAF farmers, as many other farmers do something called IPM (Integrated Pest Management) which encourages us to use lots of other options before resorting to a chemical solution. In the case of this field this meant looking at some options ahead of spraying, including:

1. A long rotation (never grown Linseed here before),
2. Increasing seed rate, to compensate for some pest damage,
3. Planting when soil temperatures are warm, (to enable the crop to establish evenly and quickly), 
4. Using no-till techniques to avoid the soil drying out (reducing establishment),
5. Removing weeds before we plant to reduce competition.

We want to farm without insecticides in the hope (and others experiences) that in the long term the build up of natural pests and predators will balance out but in the short term we need an economic return or we won't make it to the long term goal.
You can't look after the green if you are farming in the red and who pays the price for using less pesticides? At the moment the farmer carries all of the risk which if society wants us to use less artificial inputs then the reward must be greater to be able us to handle these losses. Alternatively the imports of food coming into the country must adhere to the same standards. If that's the case then currently we should not be importing any Soya beans (protein source) or Maize (corn) products from the United States as the majority are grown using plant breeding techniques not allowed in the UK and Europe and are treated with many agro-chemicals that, although safe, are not licensed in the EU.

It's a complex path that we have to tread in order to not disadvantage any UK farmers in the future. Maybe as a result of the Health and Harmony Consultation a no insecticide commitment by the farmer should be rewarded with suitable compensation for crop losses to ensure better biodiversity whilst keeping farmers in business?

Just for information the field was sprayed with a heavy heart last Thursday.