Making soil matter
Soil scientists and soil biologists may marvel at the physical and biological diversity and complex functions underground. However their perspective is not shared by all land users. An increasing proportion of the world's precious soil is deteriorating in quality. It appears global appreciation of this precious dynamic resource is - like the soil itself - steadily eroding.
While it can take up to 1000 years of complex natural forces to create 2.5cm of topsoil, in many regions it is being used up, degraded and contaminated far beyond its rate of replenishment.
So is it time for soil to be given higher priority? In Points of view this month, New Agriculturist presents opinions on the state of our soils and the challenges ahead if the earth beneath our feet is to get the attention it deserves from farmers, researchers and policy-makers.
If you want to try to understand what's wrong with developing countries then you need ask "why aren't we getting the soils right?" Development anywhere in the world has all started with the soil. But soil degradation is expanding, not contracting. I can't point to anywhere in the world where things are getting better. Whether it's the developed world - where too much fertiliser is applied and there is nutrient pollution - or the developing world where there is not enough, and soils are weakened and eroding.
Louis Verchot, Principal Scientist, World Agroforestry Center (ICRAF), Kenya
From the current situation we can say soils in China are in a very serious state. And the severity of the damage - from erosion and pollution - is increasing. According to even incomplete figures, ten per cent of arable lands are damaged.
Cheng Lifeng, Vice Director of Department of Environment Protection, State Environment Protection Administration, Beijing, China
As researchers, we come up with promising technologies and from that we develop our advice. But what can farmers do with that advice, even if they really want to improve their soils? Chemical fertiliser is too expensive. Not all of them have livestock to get manure. We have fertility tree shrubs like calliandra but the leaves need to be harvested, transported, chopped and applied and the labour required is huge. So how can the farmer afford these technologies? Poor soils and poverty - they go together.
Helen Wangechi, Research Assistant for Tropical Soil Biology and Fertility, International Center for Tropical Agriculture (CIAT), Kenya
The New Zealand Soil Society had a marvellous slogan: 'don't treat soils like dirt'. I think there are two things to be said. One is that people who work in industry or computers do need to eat food, so somebody somewhere along the line is using soil to grow food for them even if they don't see it and they just think the food comes from a supermarket. Secondly soils are an incredibly important buffer and also a sort of a crossover point between many parts of our environment. So if we want to have enough water going to the aquifers so that we have got water coming out of our taps we need to have soils in good condition. Soil scientists are fascinated by soil but I think we often do not do a very good job of explaining why it's interesting and important to our fellow citizens and I think all scientists have some share in that.
Professor David Powlson, Rothamsted Research, UK
One of the reasons why soils have not caught public attention is there isn't enough evidence of the amount of soil degradation. A lot of people hold the view that we know the problem - let's get out there and solve it. I don't accept that. Take climate change as an example. Only when there was irrefutable scientific evidence and consensus amongst the scientific community that people woke up and said "this is real, let's do something about it." I think we have not really done that yet with soils. We have not got the evidence of the degree and extent of the soil degradation going on.
Keith Shepherd, Principal Soil Scientist, ICRAF, Kenya
If you look at resource allocation, soils units are disappearing in the North. A lot of universities are closing their soils departments and going into environmental management. The discipline is being lost. Even here in Africa if you look at the national agricultural service, soils get the least budget. In the CG system we have people who work on rice, wheat, maize, cassava or bananas but soils cut across all these. We need to see soils integrated more. We are working with the New Partnership for African Development (NEPAD) on this. We produced a report on how need to see soils and soil degradation as cross-cutting issue.
Research is still needed. Not knowing the size of the problem with soil means the government is not clear on the entire area affected. This leads to inadequate policies to control soil erosion and soil pollution. We are short of relevant regulations and laws to control soil pollution. The Chinese government has promulgated laws for air and water quality conservation but unfortunately there is no such law relating to soils. We also suffer from inadequate funds or investment in this field.
I believe soil scientists have been guilty of not providing the right type of information to the right type of people. For example, everybody quotes the area of the world that is eroded. Somebody says 65 per cent of Africa is degraded. That does not come from a science-based verdict. That comes from an expert group 25 years ago. And we are still doing that. The policymakers don't have anything better.
What I believe we have to improve is our capacity to get our information on time and in modern ways - basically, the digital age. We need maps that are dynamic; something in your computer, web-based, that you can interpret for practical purposes.
Pedro Sanchez, Director of Tropical Agriculture and Rural Environment Programme at the Earth Institute, Columbia University
At the moment we have more digital maps of Mars than we have of planet Earth. The maps we do have of our soils are static but soils change over time. We need the information from the 1970s and we need to update it so farmers, scientists and modellers can use it. It will be a step beyond Google Earth when you can pick a location and get a reading about how that ecosystem is functioning. Whether it is healthy or whether it is, to use a medical term, diseased - or degraded.
Dr Marcus Walsh, Senior Research Scientist, Earth Institute, Columbia University, USA
We have new tools, digital infra-red analysis etc and new statistical methods etc to work in new ways. That's why we will move into soil surveillance as is done for public health. Not a static record but a system of case definition, risk factors, management levers, intervention testing and impact assessment. We have not really had that before for soils. Using new conceptual frameworks from other disciplines is exciting. But the capacity-building needed is huge. My dream is to get national soil surveillance systems set up in Africa in the next five-to-ten years.
Soil treated properly is quite capable of carrying on without any help from us. It's a beautifully evolved system, it is not just a collection of sand and clay and a few bugs - it's a very specifically evolved system. But we know remarkably little about it. My area of science is fascinating but we don't even really understand how the organisms break down in the soil. It's a bit like playing chess in the dark. There is much yet to be discovered and understood.
Professor Phil Brookes, Research Scientist, Rothamsted Research, UK
City people think soil is just a dirty thing because when it rains it is mud, when it is dry it is dust and so it spoils everything they want to do. But they have to contribute to how we manage our soils outside the town because it is the effect of the soil management out of the town that comes down to how we feel in town. For example if they do not educate the people outside there, we get less food in towns, we get a lot of flooding in towns.
Helen Wangechi, Research Assistant for Tropical Soil Biology and Fertility, CIAT, Kenya
We have soil care demonstrations and trial plots by schools because we have realised that although there is a lot of research, the information is not getting to the farmers. So we realised that a public institution would be the best place so that the farmers are able to come at their own free time and see exactly what is happening on the ground. And what we have realised since we started bringing the demos close to the schools, is that the children are getting more interested in farming. The students invite their parents to come to the school and see what is happening. So as far as dissemination is concerned the students have shown us a lot.
Monika MucheramunaTutorial Fellow, School of Environmental Studies, Kenyatta University, Kenya
If you look at Africa, you have got greatly impoverished soils that have been degraded over thousands of years. They contain very few nutrients, they can't grow any crops, and although they might be encouraged to recycle and practise organic farming, for example, there is nothing to recycle.
Dr Keith Goulding, Head of Soil Science, Rothamsted Research, UK
Aside from knowledge, I believe that governments have to realise the financial investment required to improve soils. We had to convince government that farmers needed to be paid. Soil work has to be economically sustainable. Government agreed to give Grain for Green, to give farmers a subsidy a payment in grain where they are greening the eroded land or giving up cultivating the steepest land. Local farmers are very happy and the scientists are very happy because it means progress is being made. The finance involved is huge but this is the price we have to accept.
Professor Guobin Liu of the Institute of Soil and Water Conservation, Yangling University, China
I think we need to understand a lot more about the interaction between the biology and the chemistry and the physics of soils. The biology is a big area, when you think about the micro-organisms present, they can be very beneficial in terms of degrading contaminants, providing nutrients to organisms and plants and animals and so on. But there is a big area of misunderstanding because we actually don't know what most of them are and so we are only scratching the surface in terms of their utilisation. We need to understand the whole system rather than just studying, let's say, the plant in isolation, or the chemistry in isolation. We really do need whole systems to be drawn together.
Professor Steve McGrath, soil scientist, Rothamsted Research, UK.
I believe that we have to get soils centre stage. So everyone - not just farmers and soil scientists - realises how important soil is to the health of the planet. Soils have become the preserve of the academic. We have students who want to be in computers, in business and in media. Where are all the bright young people who want to work in soils? We have to show how clear plans of appropriate soil care and rehabilitation are exciting. It can work. But it isn't working because all we hear is the disaster in soils all around. Do we wait another generation? We can't afford to do that.
John Liu, Director of the Environmental Education Media Project (EEMP), Beijing, China.
Date published: September 2007
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Soil is wealth. (posted by: Sam)
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