The effect of additional subsurface drainage on water discharge and nutrient load on clay soil

Helena Äijö, Maija Paasonen-Kivekäs, Merja Myllys, Jyrki Nurminen, Mika Turunen, Heidi Salo, Lassi Warsta, Harri Koivusalo, Markus Sikkilä, Laura Alakukku, Markku Puustinen

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

1 Citation (Scopus)


In the southern parts of Finland, 75% of the arable land area has subsurface drainage. Most of the subsurface drainage systems have been installed 40-50 years ago. At present, there is need to improve drainage efficiency of the old drainage systems. The aim of this study is to find out how the additional subsurface drainage affects groundwater table depth, discharge, nutrient load and crop yield. The study has been carried out at the experimental site in Jokioinen, in south-western Finland. The soil is heavy clay and the mean slope is 1%. The drain depth was 1.1 m and gravel was used as envelope material. Drain flow and tillage layer runoff from each field section have been continuously measured since May 2007. Concentrations of total nutrients and suspended solids have been determined from flow weighted composite water samples. Depth of the groundwater table and soil moisture have also been measured. According to the results, additional drainage decrease of groundwater level following snow melt and rainfall events was more rapid than before drainage. Additional drainage increased drain outflow and also nutrient loads from the drains. The results suggest that additional drainage did not affect the nutrient concentrations, apart from the peak in total nitrogen concentration in the first year after additional drainage.

Original languageEnglish
Title of host publication10th International Drainage Symposium 2016
PublisherAmerican Society of Agricultural and Biological Engineers
Number of pages6
ISBN (Electronic)9781510855250
Publication statusPublished - 1 Jan 2016
MoE publication typeA4 Article in a conference publication
EventInternational Drainage Symposium - Minneapolis, United States
Duration: 6 Sep 20169 Sep 2016
Conference number: 10


ConferenceInternational Drainage Symposium
CountryUnited States


  • Additional subsurface drainage
  • Clay soil
  • Nutrient load
  • Subsurface discharge

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