Societal challenge
Agriculture is an intensive form of land usage that impacts on the natural surroundings in many ways. Soil is cultivated intensively (e.g. ploughed, harrowed and levelled) and this consumes a considerable amount of fossil fuel. A lot of carbon dioxide is released through the cultivation of soil and the use of fossil fuels. Carbon dioxide is one of the greenhouse gases responsible for global warming. Moreover, soil cultivation and dewatering can result in the disappearance of a considerable amount of organic matter from the soil, which in turn impacts on soil fertility.
Various possibilities exist for combating the negative effects of climate change. One of the measures usable by the agricultural sector is to store more carbon in agricultural soil. This is accomplishable by increasing the soil's organic matter content (which contains roughly 50% carbon). A higher organic matter content is conducive to the moisture-retaining capacity of soil, to soil fertility and to soil life. The organic matter content also influences the efficient growth of crops, so this is of direct importance to farmers. The organic matter content can be raised by taking a variety of measures, such as fertilising with crop leftovers, using green fertilisers and by not shearing grassland.
Recommendations
Organic matter content is a good indicator of sustainable management of soil carbon. Half of the matter consists of carbon. Measures favourable to the organic matter content in soil are therefore also conducive to carbon sequestration. Particularly in agricultural land on sandy soil, there is scope to increase the organic matter content.
Measures usable to increase the organic matter content include prohibiting cultivation of the soil (with the exception of tillage cultivation), leaving crop leftovers in place, prohibiting the shearing of grassland and using green fertilisers.
A mix of measures is the most effective way of increasing carbon sequestration in the soil. Good examples are infrequent ploughing, putting crop leftovers back into the soil, injecting animal fertiliser, making suitable rotations of crops and stimulating soil life.
Policy
Authorities are putting together a policy on the sustainable use of soil. There are no laws or directives that stipulate specific standards for the organic matter content of soil. However, there is a European Soil Strategy. Its goal is to protect and to use the soil in Europe sustainably. To achieve this, the strategy seeks to prevent threats to the soil, such as contamination, erosion, salination, densification and covering. The recently amended Common Agricultural Policy also contains elements aimed at preserving sustainable soil.
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Noteworthy
Practical Network for Tillage Cultivation
A practical Network for Tillage Cultivation has produced an insight into such matters as how carbon sequestration can be factored into a construction plan. Unfortunately, it is still sometimes necessary to use chemical agents to curb unwanted vegetation.
Circular farming
Over the past years groups of farmers from all over the Netherlands have worked as 'circular farmers'. In 2013, agricultural and horticultural organisation LTO, the Rijn en IJssel Water Authority and ForFarmers Hendrix launched a project called Fertile Circular Farming in the Achterhoek and Liemers region. The project is endeavouring to inspire and to facilitate agricultural entrepreneurs in creating and seizing opportunities to increase the sustainability of their farms and to make them future-proof in terms of their operating results, environmental quality, water management and soil fertility. More than 250 dairy farmers are filling in a Circular Farming Indicator together with their advisers, with the aim of producing as efficiently as possible with the least possible addition of minerals from outside the farm.
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Maps will be available soon