Abstract
Sufficient freshwater is needed for water-dependent sectors as agriculture, nature, drinking water, and industry. Also in low-lying and flood prone countries like The Netherlands, climate change induced weather extremes, economic growth, urbanization, land subsidence and increased food production cause an increased pressure on the regional groundwater system. The average groundwater table in sandy soil areas in The Netherlands dropped since the 1970’s, with the effect that, nowadays, fresh groundwater is becoming scarce during dry periods.
Measures are needed to guarantee sufficient freshwater for all water use sectors. One of the technical solutions for the agricultural sector could be to modify the current conventional subsurface drainage systems, applied at one third of the Dutch agricultural land, to controlled drainage-subirrigation-systems. By doing so, subsurface drainage systems contribute to a shift in water management strategy: from drainage only to controlled drainage, water retention and groundwater recharge.
We used data and model output of five experimental sites of the Dutch Pleistocene uplands, and one field in the southwest of the Netherlands where controlled drainage with subirrigation is applied. Field data were collected over the years 2017-2021, like water supply, groundwater table and soil moisture content. Other water balance components, crop yield and configuration of the management of the system were modelled with SWAP (Soil-Water-Atmosphere-Plant model), using observations for calibration purposes.
Results show that by subirrigation, water can be applied to the soil and will lead to increased water storage and higher groundwater tables. Groundwater tables were up to 0.7 m higher during the growing season, leading to both higher crop yields and larger groundwater recharge. Drought vulnerability decreased at the test sites.
The effects of subirrigation on the water balance components are strongly site-dependent. For example, a loamy layer below the drainage pipes is needed to ensure enough resistance to prevent downward recharge and to raise the phreatic groundwater level. Furthermore, ditch levels surrounding agricultural fields need to be adjusted to the raised groundwater levels, as too low ditch water levels result in (unfavorable) drainage and loss of groundwater. Also, subirrigation is not effective to increase crop production in areas with high groundwater recharge rates. Field experiments also show that proper drainage system management is important to prevent clogging.
Construction, topographical location, and proper management are important for subirrigation to be successful. Responsible implementation of subirrigation in terms of the water balance at the regional scale is needed; freshwater availability to apply subirrigation is an issue. When these boundary conditions are met, controlled drainage with subirrigation could raise the groundwater level and improve the soil moisture conditions for crop growth, while still having the option to discharge water when needed.
Measures are needed to guarantee sufficient freshwater for all water use sectors. One of the technical solutions for the agricultural sector could be to modify the current conventional subsurface drainage systems, applied at one third of the Dutch agricultural land, to controlled drainage-subirrigation-systems. By doing so, subsurface drainage systems contribute to a shift in water management strategy: from drainage only to controlled drainage, water retention and groundwater recharge.
We used data and model output of five experimental sites of the Dutch Pleistocene uplands, and one field in the southwest of the Netherlands where controlled drainage with subirrigation is applied. Field data were collected over the years 2017-2021, like water supply, groundwater table and soil moisture content. Other water balance components, crop yield and configuration of the management of the system were modelled with SWAP (Soil-Water-Atmosphere-Plant model), using observations for calibration purposes.
Results show that by subirrigation, water can be applied to the soil and will lead to increased water storage and higher groundwater tables. Groundwater tables were up to 0.7 m higher during the growing season, leading to both higher crop yields and larger groundwater recharge. Drought vulnerability decreased at the test sites.
The effects of subirrigation on the water balance components are strongly site-dependent. For example, a loamy layer below the drainage pipes is needed to ensure enough resistance to prevent downward recharge and to raise the phreatic groundwater level. Furthermore, ditch levels surrounding agricultural fields need to be adjusted to the raised groundwater levels, as too low ditch water levels result in (unfavorable) drainage and loss of groundwater. Also, subirrigation is not effective to increase crop production in areas with high groundwater recharge rates. Field experiments also show that proper drainage system management is important to prevent clogging.
Construction, topographical location, and proper management are important for subirrigation to be successful. Responsible implementation of subirrigation in terms of the water balance at the regional scale is needed; freshwater availability to apply subirrigation is an issue. When these boundary conditions are met, controlled drainage with subirrigation could raise the groundwater level and improve the soil moisture conditions for crop growth, while still having the option to discharge water when needed.
| Original language | English |
|---|---|
| Publication status | Published - 26 Sept 2022 |
| Event | Studiedag - Peilbeheer: monitoring, modellering en beheer - Graaf de Ferrisgebouw, Brussel, Belgium Duration: 10 Nov 2022 → … https://curvenote.com/@ilvo_plant/book-of-abstracts/blank |
Conference/symposium
| Conference/symposium | Studiedag - Peilbeheer: monitoring, modellering en beheer |
|---|---|
| Country/Territory | Belgium |
| City | Brussel |
| Period | 10/11/22 → … |
| Internet address |
