Pesticides are currently used in agriculture to combat disease and infestation. But these products have a downside for the environment, including water quality degradation. And there's more bad news, because they also impair harmless organisms, thus reducing the efficiency of ecosystems to an extent where they provide us with fewer services. There are also unanswered questions about how pesticides impact on the health of arable farmers and local residents.
Natural capital offers ways of reducing the use of pesticides. Besides alternating crops, we can enlist the help of the natural enemies of the causers of disease and infestation. The helpers include wasps, lady beetles and birds.
The natural regulation of diseases and pests is accomplishable by improving the living conditions of their natural enemies. A practical way of doing this is by putting up green borders around the perimeters of fields. This can be accompanied by maintaining a varied landscape (i.e. a semi-open landscape with some vegetation and buildings).
The recommended way of reducing or perhaps even ending the use of pesticides is by promoting natural disease and pest control. One way of doing this is by creating better living conditions for the natural enemies of the causers of disease and infestation.
The hands-on approach is to erect borders around crop fields. These are permanent zones with a width of at least 3 metres where crops are not grown and instead grass or mixed flowers are sewn. The zones provide a habitat for insects and birds, the natural enemies of the pathogens. Creating green belts around the field has a similar effect, provided that they are not more than 50 metres apart.
Field borders have other advantages, too. As they encircle the field and have permanent vegetation, they greatly reduce the runoff of rain and other water into ditches. The result is a considerable improvement of surface water quality and a lower water treatment bill for the local water authority. What's more, they make the landscape more varied and more attractive, especially in spring and summer when flowers blossom. This will attract more tourists and revive recreational activities.
Although it is not obligatory to put up field borders at least 3 metres wide, it has been encouraged and subsidised in recent years under the EU's Common Agricultural Policy. This has enabled considerable experience to be gained and the effectiveness of the approach to be demonstrated. This stimulation will be continued under the new Common Agricultural Policy that runs until 2020.
It is also true that creating field borders is not (yet) profitable for a farmer without a subsidy. That is why it is crucial to keep in place the funding available under the Common Agricultural Policy.
General rules apply to the use of pesticides. A salient point regarding field borders is that the Discharges Decree of the Netherlands stipulates a mandatory spray-free zone of 0.5 metres. A width of this kind cannot be termed a field border, however. It is too small to promote sufficiently the living conditions of the natural enemies of the causers of disease and infestation. The sole purpose of the spray-free zone is to mitigate deterioration of surface water quality.
A project called Hoeksche Randen that began in 2003 in the Hoekse Waard region in South Holland province is the first of its kind. By such means as field borders, local farmers have reduced the use of pesticides in grain and potato crops by 100%! So creating herbaceous field borders has yielded benefits for soil, water, the water authority, local residents and, last but not least, the farmer.
With support from the Ministry of Economic Affairs and money from the Common Agricultural Fund, no fewer than 550 farmers all over the Netherlands are working on herbaceous field borders specially developed to provide a home for the natural enemies of pathogens. Since 2011 these farmers have created hundreds of kilometres of field borders. The farmers are being assisted by more than 30 regional partners, including ZLTO, an organisation that represents the interests or entrepreneurs in the green areas in the southern part of the Netherlands.