Predicting the soil moisture conditions of Irish grasslands

Abstract

Soil moisture conditions are an important interface between agriculture and the environment, as they impact on the length of the grazing season, grass growth rate and nutrient uptake, and the loss of nutrients to the wider environment. Moisture conditions are conveniently quantified by the soil moisture deficit (SMD) but diverging methods for deriving SMD have been applied in Ireland to date. A simple hybrid model for computing SMD is presented, which accounts for differences in drainage regimes between soil types, and is calibrated for contrasting soil types in Ireland. This hybrid model accurately predicted the temporal patterns of SMD on well-drained and poorly-drained soils. Three soil drainage classes were defined, which satisfactorily describe the differences in drainage between soils.