Agricultural engineer José A. Gomez of the Spanish National Research Council researches soil management systems in agricultural areas. He also is the project coordinator of the Horizon 2020 funded project TUdi that develops solutions for restoring soil health.
It is estimated that 60-70% of European soils are in an unhealthy state – why is this an important issue, particularly for agricultural systems?
The big issue is how to prevent soil erosion and to try to maintain the biodiversity and organic content of the soil. There is also the issue of contamination, over fertilisation, or a lack of nutrients. This is what makes soil inadequate, contributing to this 70% of soils being in a degraded state.
Intensification of agriculture is a major driver of soil degradation, alongside poor management, in that there are many outdated systems that are not well suited. Then, land use is a big issue, for example with good soils being pulverised or being used for industrial purposes, driving the loss of quality soil for the future.
Although a big fraction of our soil is in a degraded state, it is not all of the same intensity. For example, if fertile soil is eroded, you cannot get it back, as soil formation can take hundreds of years. But, if you have degradation of soil organic matter content, you can reverse that situation in a few decades. If the soil is contaminated with lead, there is little you can do about that, but if you have over fertilised soil, you can correct that. And so that 70% covers several different situations.
The proposed Directive on soil monitoring and resilience aims to harmonise soil monitoring, why is this needed?
José A. Gomez: If you do not have reliable numbers on a situation, there is very little you can do about it. In the European Union soil monitoring is very uneven among countries. There was an attempt for a previous soil directive [the Soil Framework Directive in 2006] that was not approved, but I feel this current proposal is more pragmatic. We need something that can be feasible and relevant in the medium term, and the harmonisation of soil quality monitoring in Europe is a wise thing.
There are disparities in how countries use systems of soil monitoring, such as for agricultural use or for other environmental uses like forestry. Some countries have much better monitoring systems than others and have policies better orientated to national policies and management practices. So it is difficult to make progress in soil unless we agree on a common system of monitoring, which as a focus of the Directive, I think most people will welcome.
At the end of the day, some of the sustainable practices in agriculture are a compromise between what you want to achieve ideally and what can be achieved feasibly. Not all farms are of the same size or have the same equipment, while some good management practices will have greater risks for production. From that point of view, you need to be a bit flexible. It can be tricky to legislate on reaching this compromise because you cannot be too flexible otherwise you will not push in the right direction.
What kind of practices are good for sustainable soil management?
José A. Gomez: Some good sustainable practices we have been talking about for many decades, the problem is how to apply them. In terms of good management practices in many areas of Europe, one is to try to have a cropping system that maximises soil cover and minimises or avoids ploughing by doing direct drilling. This means there are always established plants in the soil and so the soil will be protected from rainfall or wind erosion, and have organic matter. You can try to have a return of biomass or incorporate organic additions or manure from nearby farms to increase organic carbon and minimise soil disruption and compaction.
These kind of practices can be done in soils in the Mediterranean and parts of Central Europe where it is not too humid. For example, vineyards or olive orchards in Italy or Spain, you often do not see green vegetation between the trees, you see the soil. If you allow vegetation to grow between the trees, you protect the soil and you return biomass. But these techniques need to be fine-tuned to avoid the vegetation taking too much water from the soil and away from the crops – the detail is how to put this into practice in specific situations.
You are the project coordinator for the EU-funded TUdi (Transforming Unsustainable management of soils in key agricultural systems in EU and China) project – what is the goal of the project?
José A. Gomez: The project is based around three goals. One is cooperation: European and Chinese teams working together. Secondly, we are trying to build a database of long-term experiments where sustainable practices have been put into use and to have the data available for monitoring, testing or training. The third goal is to develop different tools to diagnose specific issues on a farm and decide which sustainable practice will be best suited for its conditions to start rebuilding soil.
For example, soil compaction is a big issue in some places. For tools to check this, you can use a kind of penetrometer that we develop and from there, depending on the condition of the soil, you can see what kind of techniques could work to alleviate the compaction. These tools will mostly be smartphone applications and will cover soil compaction, carbon content, soil biology, soil erosion and soil fertilisation.
We have another tool for an appraisal of cost-benefit analysis of the solutions, which can help train farmers or technicians and further discussions with policymakers. We would like to have a legacy for the project with an applied dimension in real world situations.
The proposed Directive sets a goal of healthy soils in Europe by 2050 – do you think this is ambitious enough? What more could be done?
José A. Gomez: I do think it is ambitious. For me, the issue is that it is quite complicated to implement soil management practices and to refine them to a specific situation. Previously in agriculture research, many countries had soil advisors that belonged to a university or government body and they held a key role in connecting science and implementation – they understood what was going on, had the trust of farmers, and could give feedback. This system has disappeared somewhat or is quite weak now in agriculture.
We know the goal and we have the science but we lack this integral part of the system to bridge the gap between scientific and technological development and fine-tune this to the field. If we invest money from projects into such initiatives for soil, building them into the system, we could get a much better return on the science being funded.