The gross- and net-irrigation requirements of crops and model farms with different root zone capacities at ten locations in Denmark 1990-2015
DCA rapport, nr. 112, 2018
Af Loraine ten Damme og Mathias Neumann Andersen
More than 450,000 ha of agricultural land are under irrigation in Denmark. In dry years, the water abstraction for irrigation surpasses all other uses in western parts of the country. It is therefore important to have as precise and recent figures as possible as a basis for issuing water abstraction permits for irrigation. Here we present estimates of the gross and net irrigation water requirements for a range of agricultural crops and model farms in 10 locations across Denmark for the years 1990-2015. We generally found higher values for the irrigation requirement than previous studies conducted 40 years ago.
The annual irrigation water requirement varied according to farm type (dairy, arable/pig and potatoes), location,soil type and especially year with more than 300%. Abstraction permits based on average values are deemed less suitable as they may restrict farmers’ production in one out of two years. When considering that many farmers’irrigation capacity is limited to about 3 mm/day, abstraction permits covering the irrigation requirement in 8 out of 10 years seems more appropriate in areas with sufficient water resources.