In sub-humid areas supplementary irrigation is a rather important precondition for the commercial cultivation of berries. But due to the high price of irrigation systems and low incomes, some farmers prefer alternative approaches to irrigation systems. Mulching is considered the most important cultural practice as it plays an essential role in soil moisture conservation. In order to clarify and evaluate the influence of mulching in sub-humid areas on active soil water amounts, depletion during vegetation, our the investigation was conducted in a strawberry field (54º88’N, 23º09’E) on light loam (IDg4-k) soils. Chopped wheat straw and black plastic were used as organic and non-organic mulches. The present study revealed that the soil moisture content differed significantly and appropriate mulching of top soil layer was quite useful in the field to accelerate growth and get high fruit yield. The highest average weight-based soil moisture content of the active soil layer (0-40) within three years was 18.0% in the field mulched with straw, while the lowest one, 16.2%, was in the field without mulching; in the plot mulched with black polyethylene it was 16.5%. The yield of two years gained from the field mulched with the black polyethylene layer was higher by 60% than that in the nonmulched field and by 56% in comparison to the yield in the plot mulched with straw.