Kevin Hobbs reflects on the National Soil Symposium 2013

Written by Kevin Hobbs

I had not been to a symposium before, nor can I remember being addressed as a delegate so I was excited as the eve of the Soil Symposium 2013 finally came around. Nowadays a symposium is a fancy name for a conference but back in ancient Greek times it was a drinking party after dinner that sometimes led to lively philosophical and wide ranging discussions such as now sometimes take place down at the local boozer. But this symposium in Bristol we attended out of personal interest and because, I have to say despite the risk of sounding over dramatic, we know the subject matter to be of vital importance to the future of us human’s as a species and all the plants and animals we know and love.

There is no doubt that we all need food in order to exist and in recent times the majority of food has come to be grown using chemically synthesized fertilizers that require a lot of energy to produce. The fact that this situation is only economical as long there is an abundance of cheap energy is a potentially unsettling thought as is the fact that on average 1 calorie of food requires 10 calories of fossil fuels to grow, harvest and process before it gets into your belly. The points are illustrated well in the BBC Natural World documentary, A Farm for the Future, that you can find on YouTube. But what is all this doing to our soil? This is what we came to find out.

In the first lecture of the day Dr.Urs Niggli of the Research Institute of Organic Agriculture, Switzerland demonstrated that yes we can do all the sums and add the right quantities of N, P & K and get an abundance of great looking crops but we will do so at the expense of soil structure which is intrinsically linked to the soils natural ability to be fertile. I think this is the cause of the problem Professor Carlo Leifert describes in the video embedded on this page which comes from the last years soil symposium. The fact is that as time goes on larger quantities of fertilizer have to go into the soil in order to maintain the same levels of production. Quantities of inputs are still going up but the total yield remains constant.

I won’t attempt to give a summary of every lecture we saw at the National Soil Symposium 2013 as my note taking skills are not quite up to the task. I hope you will all get the chance to watch the lectures on YouTube when the Soil Association get them online. We will be sure to post another link when this happens.

I think the take home group of facts for me are all related to the fact that soil is a massively complicated living system which can support fertility if we manage it correctly. Dr Niggli introduced us to a new concept, Ecofunctional Intensification, defined as “Using ecosystem functions to intensify production”. The soils ecosystem functions are supported and performed by a microbial mass of flora and forna. We heard that there are more living organisms in a cubic centimeter of soil than there are human beings on the planet and they rely on soil structure for there existence. In turn that soil structure is supported by organic matter.

The shock fact was that if one unbalances the system by adding too much nitrogen the microbes bloom and break down excessive amounts organic matter and thus over time there is degradation of soil structure and then the soil maybe blown blown away when it is dry or washed into rivers when it rains. We heard worrying figures regarding global rates of soil loss from agricultural land and the impact this will have on food security. Another lecturer announced that soil fertility building and soil conservation are the most important competences of organic farmers.

Charlotte said, “Some things that really struck me were that soil is the frontier of cutting edge science – we know really very little about this complex substance we fundamentally rely upon. This can make it very overwhelming as a grower – where to start to address the 17 essential elements that plants need to thrive?! Nevertheless I felt encouraged and inspired to observe and consider the health of our soil better, and to try to think of myself more as a grower of soil rather than a grower of veg! ”

It was heartening to learn that we are already doing the right thing by putting green waste compost on the land to increase organic matter and recycling our phosphorus by composting our plant waste. Don’t worry folks we are not putting sewage or any other kind of “humanure” on the land but we can see how as Carlo Leifert lecture suggests, this is something that people might have to swallow in the future!