Summary:

Assessment of soil moisture conditions on permanent grassland in Poland is made within the nationwide monitoring of water deficit and surplus in agriculture performed by Institute of Technology and Life Sciences from 2013. Soil moisture index SMI is used to categorize soil moisture in the end of each 10-day period during the vegetation period (April-September), using the original classification proposed by the authors. SMI enables the comparison of moisture conditions in soils with different water retention and the objective evaluation of soil drought and water excess. Assessment is made for grassland in wet, moist, periodically dry and dry habitats in 2013-2014. In wet and moist habitats soil moisture was in the optimal range for grassland plants and meteorological conditions affected in small degree. In periodically and dry habitats soil moisture was more differentiated and was affected by actual meteorological conditions greater. Soil droughts dominated.