The European Union has imposed rules on its members with the aim of reducing CO2 emissions. This is better for the environment and therefore better for people. It is a society-wide problem which is being tackled in a number of ways. The fact that coal fired power stations and cars are often named as the major culprits is well known. Not quite so well known is the fact that the peat meadow area also contributes to these emissions. Peat oxidation represents 2 to 3% of the total emissions in the Netherlands. This can be halved, simply by applying drain pipes below ditch level.
When converted, Dutch peat meadows emit an amount of CO2 equivalent to the amount emitted by a large coal-fired power station
Around the year 0, half of the Netherlands was composed of peatland. That has largely disappeared because people started farming the land, digging canals with ditches criss-crossing them. In the process, the peat was drained. Throughout the country, peat was burnt because it was a cheap fuel. So peat was a source of prosperity, a type of soil which made the Netherlands a country to be reckoned with. Currently, the few peatlands left are depleted because of peat oxidation. Drainage causes the surface water table to drop and if, as a consequence, oxygen is allowed in, all the organic material will disappear into the air in the form of CO2. This generates considerable CO2 emissions, amounting to some 20 tons per hectare per year, which is exactly what the government wants to restrict. The other major problem is subsidence, amounting to approximately one centimetre per year. The question is: how can you limit oxidation as much as possible? The solution lies in the application of underwater drains to raise the groundwater level. In agricultural practice, the use of drain pipes is very common. In the Netherlands, thousands of kilometres of drain pipes have been laid under ground level in order to keep things dry. But many of those drains lie above ditch level, whereas this study shows that, in the case of peatlands, it is preferable to lay them some 20 centimetres below ditch level.
The Netherlands is situated some 2 metres below sea level, and as a result of peat oxidation it will sink another metre during this century. In the future, this will cause problems. Because of the peat oxidation, subsidence also adversely affects the water. If the soil keeps sinking, you get more seepage water, which contains a high degree of nutrients which is bad for the water in the ditches. The problem in the peat meadow area is that in dry summers, the infiltration of ditch water into the plot is insufficient to keep up with the evaporation from the grass. This frequently causes the groundwater level to drop as far as 40 centimetres below ditch level. Even raising the ditch level considerably will not sufficiently facilitate infiltration, and will have serious drawbacks for agriculture. If the drains are laid some 20 centimetres deeper than ditch level, as I propose, the water will infiltrate as far as the middle of the land, and will ensure that the groundwater level will approximately reach the ditch water level. So the drains will provide every part of the land with water during dry summers, and will drain off the water in winter, when it rains a lot and the land is too wet. Consequently, it is a good solution for the dairy farmer as well.
We have been working on this study for ten years, so there are several ongoing pilots. Right now we are fine tuning our research. We have carried out research in the western part of the Netherlands, but not yet in the peatlands in the north of the Netherlands. The problem we encounter is how to persuade farmers to lay underwater drains. It is a long term investment, which of course costs money; farmers can invest in a number of ways which will bring in money more directly. However, if they decide to make this investment, they have a major advantage over other farmers, quite apart from the conservation of land - in the early spring they can start working their land ahead of others as it is not so wet. In the autumn, the cows can benefit from the grass and stay out in the meadow longer.
There are two problems underlying this study. The first serious problem behind peat oxidation is climate change. The EU intends to progressively reduce CO2 emissions from agriculture per country. At present, CO2 emissions from peatlands represent 2 to 3% of total Dutch emissions. When converted, Dutch peat meadows annually emit the equivalent amount of CO2 of a large coal-fired power station which is in operation all year round. In actual fact, total EU emissions from peat oxidation equal the total annual emissions in Belgium. If the groundwater level were to be kept at ditch level by means of those drain pipes, CO2 emissions can be halved to 1 – 1.5%. Secondly, the ground level drop is problematic, because you do not want even more subsidence in addition to the rising sea level. A social cost-benefit analysis with regard to subsidence shows that this is becoming a major economic burden, one thatwill continue to increase. River dykes and peat dykes will have to protect sinking – often densely built-up - peat meadow areas. Applying underwater drains can facilitate the handling of the subsidence rate and consequently keep the costs down.
When I started out in the eighties as a young researcher, the monitoring of the ground level drop in peat meadow areas was a small project for which I was made responsible. It is difficult to find financing for monitoring, and for years it was an ailing project that could only proceed thanks to several researchers working on it in their spare time. In due course we succeeded in making a wider audience aware of the fact that subsidence and CO2 from peat meadow areas are linked to climate change and the rising sea level. This, plus an EU project (EUROPEAT) for which I was the coordinator, made it possible to really start looking for solutions. In 2003, in collaboration with colleagues from what is now called Wageningen UR Livestock Research and the at the time experimental farm Zegveld - now Veenweide Innovatie Centrum, VIC (Peat Meadow Innovation Centre) - the first underwater drains were laid, followed by a number of projects carried out in partnership with the different water boards and provinces of the western peat meadow area and LTO (Dutch Federation of Agriculture and Horticulture). Currently, two EU projects are running in which we propagate the application of underwater drains.
Application of underwater drains can make an important contribution to the reduction of CO2 emissions and the control of subsidence: two problems for which the various governments are of course responsible. In this respect, it should be borne in mind that peat oxidation, and consequently subsidence, are strongly on the increase as a result of climate change. Applying underwater drains will also make the peat meadow area much more climate resilient. For the planning as well as the execution of projects with underwater drains, good advice is essential, especially because it often calls for a tailor-made approach. If the reduction of CO2 emissions is recognised in terms of carbon credits, construction costs can soon be paid out of those, and with higher rates for carbon credits, good money could be made. This is a new market awaiting drainage companies. It is important that these companies provide high quality, because a drain that is not laid flat and is bumpy, causing it to rise above ditch level somewhere along the line, cannot infiltrate the ditch water and won’t work.
For a start, it would be ideal if this system were to be made operable throughout the Netherlands. This would result in much more climate resilient peat meadows and a significant reduction of CO2 emissions. To achieve this, it is vital that, first of all, we solve the question of who is going to pay. Once that hurdle has been taken, other countries can follow. At present we are working on two international projects, because there are peat meadow areas in many Northern European countries. In Germany they have the same problem that we have in the Netherlands, but with 10 times the amount of peatlands used agriculturally. Interest has already been expressed in establishing a pilot there. This can be followed by countries such as Poland, Norway, Sweden, Finland, Russia, Belarus and the Ukraine, but also by countries outside Europe.
GHG emissions peat soils, mitigation CO2 emissions, climate change and adaptation peat soils, peat soils in agricultural use, subsidence of peat soils, soil degradation, submerged drains, Voluntary Carbon Credits (VCC) and Carbon Credits (CC)