Podcast: Monitoring soil health and complexity

Muck heap

26 November 2013 by Sue Nelson

This week in the Planet Earth podcast, Karl Ritz and Robert Simmons of Cranfield University, and Guy Thallon from fresh produce company Produce World, talk about how they manage one of the most crucial ingredients needed to grow vegetables - soil.

To assist those who find text-based content more accessible than audio, a transcript of this recording is available below.

Sue Nelson: This time on the Planet Earth podcast, how a collaboration between scientists and food suppliers called Soil for Life is improving the management of one of the most crucial ingredients needed for growing vegetables.

Hello, I'm Sue Nelson and today's podcast is from outside the National Soil Resources Institute at Cranfield University in Bedfordshire and I'm joined by Professor Karl Ritz, Dr Robert Simmons and Guy Thallon.

We're actually, appropriately enough, standing of course on some soil and in this case on a park, a sort of playing field with a tennis court to the side, cricket pitch and some nets and I'm going to start with the most basic of questions to you, Karl. Considering we take soil for granted and some of us may even have eaten it as a child, what exactly is soil?

Karl Ritz: Soil is one of the most remarkable materials on the planet, Sue. It's comprised of a wide range of mineral grains, mineral components, organic matter and most importantly of all space. Soil is a porous material and it's those pores that make it special in terms of how it holds water, it allows plant roots to penetrate the soil and grow down and it provides a habitat for the myriad of organisms that live in soil that drive so many of the processes that are recurring to make it function.

Sue Nelson: So what makes a good soil?

Karl Ritz: We like to think about a good soil as one that is fit for purpose. So it depends what you want the soil to do - if you want to grow materials in it or if you want to, as we have here, make a cricket pitch out of it, then you would require different properties in that soil.

Sue Nelson: Okay then, let's go to Rob. What makes a good soil then for growing vegetables?

Robert Simmons: Specifically for vegetables, then we would be looking at a soil which is freely drained, able to form a good tilth-

Sue Nelson: Tilth? What's that?

Robert Simmons: A good tilth, that's a crumby structure that will allow good contact between your seed and your soil allowing good germination but it also means that the soil is free draining and you need a soil that is able to retain and release nutrients, has good aeration but also once you've moved past that then soils become very specific, very crop specific, so you would want a different sort of soil for onions, alliums, roots, for example.

Sue Nelson: What actually has happened when a soil has been overused as can be the case when it's intensively farmed for things like vegetables for supermarkets?

Robert Simmons: A number of things can happen. Effectively the soil is getting tired. There's a term they use in Lincolnshire, 'whacked' for example. What effectively is happening is your soil begins to degrade. It starts to lose its ability to perform certain functions, so your soil can become compact from trafficking when the soil is the wrong moisture content, for example, and that impacts on soil structure, impacts on the ability of your soil to receive, retain and release water. Your soils, can as a declining soil structure through lack of organic matter through this intensive production system, can impact on your soil microbial health and the nutrient recycling etcetera and the structural integrity to that microbiology in parts to soils, and also you start having problems with capping of the surface where the soil surface breaks down under rainfall and it forms a cap so the water can no longer infiltrate into that soil. The crop therefore cannot get adequate water that it needs to achieve its optimum yields but also what you have, and this is why rotation becomes important, you can start building up soil borne disease in your soils.

So for potatoes, for example, potato cyst nematodes and other crops will have specific diseases that can build up in soils and it makes those soils no longer suitable for those crops. Or if you are growing crops, for example, potatoes then you need to start looking at maybe some chemical solutions, so nematocides but also at looking at more initiative solutions such as break crops, bio fumigants etcetera.

Sue Nelson: It's probably a good time to go back over to you then, Karl, because several years ago you came up with an idea to help growers monitor their soil, why? Surely growers, farms, probably keep an eye on this sort of thing themselves.

Karl Ritz: Individual growers and farmers of course have been monitoring their soils regularly over many years but the difference is that the landscape is changing in agriculture now where these farmers are providing their material to supplier companies and that means that things are changing scale. And what's happening is that each individual grower would have data relating to their fields and produce from their farm, but at the supplier scale hitherto much that data has just remained isolated and therefore not of so much use. If the data can be integrated in some way that can provide some very important business related information for the supplier and back to the growers.

Sue Nelson: And this led to a link with Produce World who are one of the largest suppliers of vegetables in Europe and they supply most of the supermarkets, main supermarkets in the UK, and this is where you come in, Guy Thallon, because you've been working with Produce World on the Soil for Life project. So what did you actually do?

Guy Thallon: I worked with Produce World for three years on that project and we looked at bringing together data and the type of data that Karl was speaking about, farm system data really, and bringing it together in one data holding where you can analyse it and look at it like by like.

Sue Nelson: How did you do that?

Guy Thallon: A combination of working with farmers and growers. Produce World are, as you say, a large fresh produce company. They supply alliums, so onions and leeks, brassicas, broccoli, cauliflower, green leafy veg, potatoes and root crops into the UK supermarkets. About a third of that they farm in their own right on their own farms and then the other two thirds are from partner farms and growers. So throughout the projects I was working with our own in-house farming that Produce World do but then also with the partner farms and talking with them about the land that they're farming on and identifying the land that they farming on and kind of mapping it out and then using the data that they have in-house and they've invested in it in terms of their crop management and farm management type of data, their annual nutrition data, information about their machinery and their farm gear and information about the kind of fertilisers and the crop nutrition side of things.

Sue Nelson: And yield as well I assume?

Guy Thallon: Yes, absolutely. So the benefits of working with Produce World is that they're a pack house, they're suppliers so they have really in-depth detail on the yield and quality of produce coming through. So it's not necessarily about getting the most off the land, it's getting the most off which is of saleable quality, so marketable yield really.

Sue Nelson: So did you just do this on site with a laptop while you were there?

Guy Thallon: Yeah. Thankfully I did have a laptop so I was moving around visiting farmers and growers and basically asking them to contribute data. We set up an information system so the Soil for Life itself is a database and information system which allows people to identify fields and then to link that data onto those fields so that it begins aggregating on its own, and then we use that date to look at a number of different case studies but also just to do benchmarking and understanding where different growers sit in terms of different contexts and different soils.

Sue Nelson: Karl, what sort of an impact then is this new Soil for Life database going to have now that you've got all this information in it?

Karl Ritz: For the first time what it is doing is it's starting to create a large scale database that crucially is coherent, which means that the data will be growing year on year and is relatable each to the other. If you just have a lot of different data sources coming from all over the place then this is incoherent and less powerful. So the fact that the data is connected means that we can start to explore it in new ways using what's called data mining techniques - these are new statistical tools that we can use to look at large scale data. One of the phrases used is 'big data' and this is becoming common in genetics but here we're applying that concept in an environmental informatics type concept and context.

Sue Nelson: Rob, what sort of an impact will this have on commercial growers and suppliers then? Will it improve their soil? Will it improve their yields, their vegetables?

Robert Simmons: Absolutely. A number of growers and major UK suppliers may lose 40% of product through defects. Now if they can utilise Soil for Life to identify soils, agronomic practices which most effectively generate marketable yield they can reduce their wastage. They can all start looking at fertiliser inputs, other management tillage practices that can optimise marketable yield and reduce inputs. Another input is water. So if we're looking at irrigation use efficiencies etcetera and then the beauty of the Soil for Life system is that you can also start making economic assessments of your production system, so where you can start making savings, not just in terms of fertiliser but in terms of energy and carbon etcetera.

Sue Nelson: Guy, what sort of an area is the database covering at the moment?

Guy Thallon: Predominantly the database covers the east of England at the moment, so most of Produce World's farms and growers are in South Lincolnshire and then spreading out over East Anglia. We have about 800 fields which we've got capture within and those field then have data attributed to them and that covers an area of about 10,000 hectares in total.

Sue Nelson: And can you use this for policy as well then?

Guy Thallon: Food production is really high on the UK government's agenda. We had the UK Agri-tech Strategy which was published this year which puts the idea of sustainable intensification, which is a kind of buzz word, but basically looks to increase the amount that we're producing in terms of food production and increasing net output whilst decreasing the environmental impacts, so minimising the amount of damage that you are doing to resources such as soil. By managing Lambank in the way that we've been doing with Soil for Life, and in the way that Produce World continue to do, utilising some of the data that we've got in there and the understanding that you can derive from that there's huge benefits to be had in terms of driving forward that sustainable intensification agenda.

Sue Nelson: Professor Karl Ritz, Dr Robert Simmons and Guy Thallon, thank you all very much from the National Soil Resources Institute at Cranfield University here. You've been listening to the Planet Earth podcast from the National Environment Research Council and do check out our Facebook page and Twitter feed.