Research project Opportunities for controlled drainage in Flanders

General introduction

With its concrete results and approach, the OP-PEIL research project succeeded in increasing the applicability of controlled drainage (CD) in Flemish agricultural soils. OP-PEIL provided concrete figures on the effectiveness and profitability of sub-irrigation and of CD as a technique to control salinization. Models were also used to make a first estimate of how much more water can effectively infiltrate to groundwater through CD in the various applications, and to what extent this also gives more yield.

Controlled drainage does not drain water continuously, as with conventional drainage, but allows water to be drained at times when it is really needed, for example during the sowing period. In other words, CD is a smarter, more water-efficient system for keeping appropriate amounts of fresh water under agricultural plots. This form of drainage can be both socially and agriculturally profitable as well as effective in the short term.

Research approach

In addition to applying and implementing existing knowledge, OP-PEIL created new insights around three knowledge gaps: the potential of sub-irrigation (supplying water underground via the drainage system), the influence of CD on salinization in the polder context, and the possibilities for collective water management on a landscape scale.
OP-PEIL actively focused on (i) Providing decision support guidelines and practical recommendations to companies on the plot-specific application of CD; (ii) Encouraging and guiding targeted farms in the conversion from traditional drainage to CD, with an emphasis on installing a feasible and financially viable CD system; (iii) Maximizing the dissemination of knowledge about CD to farmers and authorities, both by the project team and by the farmers of the target group through demonstration activities and workshops.

Relevance/Valorization

The results of OP-PEIL have led to increased application of CD in Flanders and more attention for context-specific needs. The research was also taken up by policymakers and incorporated into the development of new regulations. In response, the project produced a policy note that identified specific problems in the field. OP-PEIL provided concrete figures on the effectiveness and profitability of sub-irrigation and PGD as a technique for controlling salinization in field experiments. Using models, we calculated how much more water effectively infiltrates into the groundwater through CD in the various applications of the project and whether this also results in additional yield. Further results include increased knowledge among farmers and authorities and a practical exploration of the potential of collective water level management.