Inspirational ideas: Climate-adaptive soil moisture management

Climate change is not only causing new weather trends, but also extreme weather events. In both the short and the long term, weather unpredictability and highly variable weather patterns are challenging farm management as well as food productivity and stability. The EU Adaptation strategy which is part of the European Green Deal, sets out how the European Union can adapt to the unavoidable impacts of climate change. This ties in to the CAP objective ‘climate change action’ which is taken up through CAP funding including Operational Groups.

Soil compaction and its consequences is a significant soil threat in the whole of the Netherlands. It strongly influences the soil moisture balance and leads to a greater sensitivity to precipitation surplus and deficit, which is exacerbated by climate change. Novifarm is a cooperation of 6 family farms growing mainly arable crops in Hoeksche Waard. As part of a wider initiative ‘Putting Hoeksche Waard on the map’, in 2016 Novifarm started a project called HW20 to face these ever-changing climatic conditions, and the Operational Group is part of this project.

Even though Hoeksche Waard is surrounded by freshwater, the area still has real problems with drought. Farmers tackle the dry conditions by irrigating the surface of the fields, however they encounter high rates of evaporation and energy costs. After a long dry period, heavy rains can occur and cause flooded fields. A solution is needed. So, in preparation for the HW20 project, Novifarm used field scanning technology, remote sensing and satellite data to analyse the situation and found differences in the growth of plants. Year after year they experienced more difficult soil conditions at seeding and it took more effort to maintain yields. Leon Noordam from Novifarm, explains “With this in mind, we decided to try out getting the water from underneath. This way, the crops use what they need and water isn’t wasted and upper soil structure remains intact.”

HW20 aimed to build a 3-pillar integrated water management approach designed to protect the soil and crops. The first pillar is about soil compaction – carrying out the farm work without heavy machinery. The second is about controlling water quantity – how to remove water when there is too much rain, or apply more when it’s too dry. The third pillar is on soil health – getting the soil into better shape. Leon explains “The system is like a tripod, often farmers are already implementing 1 or 2 pillars, but farms need the 3 pillars to stand and be successful.” Novifarm teamed up with 4 other farms in the area to form the Operational Group which worked from 2019-2022 specifically on the second pillar ‘Climate-adaptive soil moisture management’.

The aim was to develop a system which enables the farmer to control the ideal soil moisture balance with regards to the needs of the crop as well as biotic soil processes, to be able to make clear decisions in the case of extreme weather, use water and nutrients sparingly by buffering water for re-use and to save energy compared to irrigation.

Underground drainage/irrigation systems were installed on 5 pilot farms, including at Novifarm, covering 60 hectares of agricultural land which have different sub-soil types. As this was also part of the HW20 project, the pilot plots also used lighter machinery and brought organic material to the fields to increase organic matter. The drainpipes are 2m under the surface of the ground. Using an existing soil moisture sensor technology (Adaptive Groundwater Level Management System - aGPS©), farmers can control the soil moisture balance on a sub-parcel scale, letting water in and out of the drainage system in a controlled manner. The excess water can quickly be drained away from the parcel or spread evenly to other parts of the field. The system is also capable of holding excess water nearby in case there is subsequent need for irrigation in which case it can be let back into the system.

Since 2020, the farmers have been collecting data and analysing impact on crops. Leon says “We are still learning, but this Operational Group has already given insight on what happens to groundwater levels when there is a heavy shower, or several weeks with with no rain.. We have identified some crops which yielded much better under this system. It gives farmers much greater control when it comes to unpredictable weather conditions, and increases the farm’s capacity to face climate pressure.”

The Operational Group came to an end in 2022, but the farmers will continue to monitor progress over the coming years. Results have been demonstrated in field visits and magazine articles, this will also continue.

Contacts