Polder Rice In The Netherlands: Will It Work This Year?

Will it be possible to grow polder rice in the Netherlands for the first time this year? In any case, researchers from Wageningen University & Research (WUR) and Leiden University will try again. While it was not possible to grow rice in the Netherlands last year, this year the researchers will be even better equipped because they will be working with 32 different rice varieties. This and next week the rice will be planted in Leiden.

The project is a collaboration between researchers from the Plant Sciences Group (Tom Schut), Animal Sciences Group (Aart van der Linden) and Environmental Sciences Group (Julian Helfenstein) of WUR, and Maarten Schrama of Leiden University.

In May 2023, the researchers planted 3,000 rice plants of one species. The researchers wanted to try out rice as a middle ground for future sustainable peat management: the crop increases the water level and produces food at the same time.

Julian Helfenstein (WUR): 'Last year we started testing with rice. You should see it more as a hobby project with one type of rice from Northern Italy. The plant did grow, but the harvest was minimal. This year we will be working with 32 different types of rice. These varieties have been selected from 19000 rice varieties by GRIN-Global Plant Germplasm from the USA. We chose this rice because it is most likely the most suitable for the climate in the Netherlands. The species range from Japan to Uzbekistan to China and bear interesting names such as Tomohikari ('shining together', Japanese) and Sputnik. So this summer we will see how they are doing in the Netherlands.'

Interesting crop for the Netherlands
Transformation of agriculture on peatlands is perhaps one of the biggest challenges for the Dutch agricultural sector. By exploring the potential of rice cultivation, the researchers aim to broaden the solution space with a new, innovative pathway that can reduce environmental problems, contribute to more circular food production and provide new habitats for swamp species.

The researchers are testing the rice because the crop grows well on flooded land and could therefore be interesting for the Netherlands. The crop could thus put a stop to peat mineralization and soil subsidence. Problems with seawater intrusion and salinization can also be limited by higher groundwater levels. In addition, the wet rice fields can provide a valuable habitat for wetland species such as amphibians and dragonflies.

Fish with rice?
In addition to the experiment with the rice cultivars, research is being conducted into whether it is possible to breed catfish in the rice field. The researchers expect that the rice field will provide the fish with an attractive living environment, where the catfish can exhibit natural behavior and feed on the algae, aquatic plants and insects present. The nutrients excreted by the fish are absorbed by the rice. In this way, a circular agricultural system is designed, in which rice and fish benefit from each other's presence. The catfish catch insects that are harmful to the rice. The rice in turn provides shade and hiding places for the catfish.

Fish farming could also provide an additional source of income for farmers. This is important because rice cultivation on a large scale is only realistic if it is also financially interesting for farmers in the long term. Aart van der Linden (WUR): 'Growing sustainable, local rice and fish on peat is interesting because it can be sold at a premium and contributes to more circular agriculture. Net greenhouse gas emissions are also likely to decrease compared to current peat agriculture. Rice cultivation could be both a strategy to limit climate change and an adaptation to higher temperatures. Once we have secured the necessary funding, we aim to monitor impacts on greenhouse gases, nutrient flows, water regulation and biodiversity over the coming years to identify the best management options for the circular farming system.'

When does what take place?
The first rice plants were planted by hand this week; Next Monday, May 19, mechanical planting will begin and the fish will be added 2 weeks later. The harvest is in September.