Test fields with under-soil irrigation tubes established in the Northern Netherlands

17 March 2021 - Published by Laila Dam
In October 2019, the first under-soil irrigation tubes were installed at SPNA’s test field in cooperation with the lead partner province of Groningen. With this, the realisation of the desired salinization field became more and more concrete. Flowingly, a pumping and mixing system has also been installed.

- With this mixing station, we are able to supply fresh and salt water to sections in a controlled way. In the following months after the installation, experiences were gained with this system and a few teething problems came to light. These were largely resolved in the course of 2020. In the meantime, the monitoring system has also been installed. In autumn 2020, an additional field with drip lines was established. We are now in a position to carry out research on the effects of subsoil salinization on crops on clay soil in a controlled manner, Carina Rietema, researcher at SPNA explains.

The coming field season has already started with the seeding of winter wheat. Furthermore, onions and seed potatoes will be sown and planted in April/May. These crops will grow in various field conditions to enable us to determine the effects of the simulated saltwater-pressure from the under-soil irrigation tubes. Fresh and saltwater pressure can be compared. In addition, the effect of tilling and no tilling can be compared due to the establishment of the second field. To determine the effect of the vegetative growth of winter wheat in the field, an intern named Rowan Schreijer, started in February with observations in the field.

- I started a research project in February 2021 in which I compare and evaluate the vegetative growth differences of winter wheat on saline versus regular clay soil by using statistics. I am currently studying Applied Biology at the Aeres University of Applied Sciences in Almere, and hope to be able to complete my degree with this research, which will serve as my thesis, Rowan Schreijer explains.

In this research, Rowan has used Completely Randomised Block Design, in which he has created four blocks in both the regular and the saline soil. This principle was applied to two experimental fields, whereby one field was ploughed, and the other one was not. In each block, Rowan keeps track of the vegetative growth of three selected plants. Parameters such as leaf area, plant length, root growth, state, and plant damage are being monitored.

Figure 1 shows the unploughed trial field containing the block tests, and figure 2 shows a block test from up close.


- By measuring the above-mentioned parameters on a weekly basis over a period of 13 weeks in total, I hope to be able to analyse the effect of salinisation and/or ploughing on the vegetative growth of winter wheat by performing certain statistical ANOVA tests, Rowan concludes.

SPNA’s test fields have been featured in two movies

In a movie for the climate-adaptation week in province Groningen SPNA’s test fields are included in a clip about salinization. You can find the clip 20 minutes into the movie, which also includes an interview with researcher Carina Rietema from SPNA (the movie includes English subtitles).

Click on the photo below to see the movie



Further, the test fields are included in a movie about climate-adaptive agriculture development in the region of Groningen. You can see the movie below