Waterlogging remains a significant constraint upon crop yield in areas with high rainfall and/or poor drainage. A yield penalty ranging from 10 – 100% across all UK crops may be expected annually. Improvements to drainage always repay investment.
A crop grown under waterlogged conditions first suffers from a lack of oxygen; the primary cause of limitations upon plant growth. When soils become waterlogged less gas diffuses to and from the roots through the soil pores; there are changes in concentrations of mineral elements in soil solutions and toxic products of roots and soil microorganisms begin to accumulate.
Improved soil management can increase water infiltration, reduce surface runoff and additionally improve availability of water and nutrients to plants when they most need them.
Soil management practices such as drainage, tillage and traffic control can alter soil structure directly or indirectly. Such changes in soil structure can be persistent but are also reversible.
Land drainage is one of the main approaches to improve yield. However, drainage to combat waterlogging has almost been forgotten by advisory services and government agencies over the last 50 years. Various studies indicate that drainage can effectively lower the water table and improve crop yields. (It really is that simple!)
Despite continued yield losses associated with waterlogging large scale adoption of drainage is still limited. Various methods are recommended to mitigate waterlogging problems, such as surface drainage, subsurface drainage, and mole drains but possibly due in part to cost they are reluctantly employed.