Saving water in Arable farming

Climate change is leading to a "hot season" in which droughts are a feature of agriculture in many places. The previously known sufficient water supply has become less certain. The increasing drought requires adjustments in arable farming; saving water is the motto. In agricultural policy, the necessary adjustments are being discussed under the catchword of resilience. Resilience is the ability of enterprises or systems to cope with disruptions. Resilience comprises three dimensions:

1. Robustness: ability of a system to withstand external shocks and negative environmental trends and to maintain basic functions.
2. Adaptability: ability of a system to adapt to changing environmental conditions and maintain all essential functions.
3. Transformation: Ability of a system to change radically to maintain key functions even when the system environment changes significantly.

Strengthening farm resilience

To strengthen the resilience of agriculture, EU agricultural policy plays a key role. This would require strengthening organic schemes to support public services such as biodiversity and adaptation to environmental and climate change. But value chains are also coming into focus. What is needed is for member states to offer comprehensive support for cooperations and to enable producer organisations to coordinate adaptations to changing markets and environmental conditions.

Less water for agriculture

Climate change has a direct impact on water availability for agriculture. This is because higher temperatures and decreasing precipitation are expected in the summer half-year. As a result, plants start evaporating earlier and also evaporate more water. As a result, soils dry out earlier in spring and more in summer. Increasingly dry soils also lead to limited recharge of groundwater, which can result in bottlenecks in groundwater supply. Regionally, the north-east of Germany and the Rhine-Main area are particularly affected.

Sufficient potassium supply

Farmers have various options for increasing the water productivity of their cropping system. Conservation tillage with or without loosening, no-till and strip-till as well as increasing the organic matter in the soil are approaches to increasing soil water contents.

When fertilising, a sufficient supply of potassium is important to strengthen the root development of the plants and thus their access to soil water. Finally, soil compaction must be avoided. Only loose soils are able to absorb large amounts of water in a short time during heavy rainfall. And the plants form more and deeper roots in loose soils.

Focus on drought-tolerant varieties

Crop rotation also offers opportunities for adaptation. Drought-tolerant varieties and crops are becoming more relevant. Low transpiration coefficients are an increasingly important parameter in variety selection.

In addition, soil that is covered all year round helps to retain water. Investigations in the Hessian AKHWA project have shown that undersowing achieved better results than reseeding in summer. This is because the undersown crops are already established in the beginning of the dry season.

Dr. Achim Schaffner,
DLG Centre of Agricultural Excellence,
Project Manager Farm Management and Organic Farming.
a.schaffner@dlg.org