Summary:

Quantity, intensity and seasonal distribution of precipitation have an indu-bitable impact on soil moisture. Precipitation water could be used by plants only when percolates into soil and is retained as capillary water. In case of excessive amount or intensity of rain, part of water percolates below the root system level or runs off at soil surface. During two years of experiment (2009-2010) quantity and intensity of precipitation were observed and analyzed. Daily and weekly measure-ments of soil water content were done to assess the impact of intensity and quantity of precipitation on soil moisture changes in apple orchard. Total rainfalls for years 2009 and 2010 were higher from the multi-year average. Also, the temporal distribution of precipitation differed within and between the analyzed years, how-ever, the amount of rainfall collected during the vegetative period (May-September) constituted more than 50% of the total yearly precipitation. The results showed low efficiency of small rains. On average, during the vegetative period, minimal precipitation necessary to keep the soil water content at a stable level was 13-14 mm during a week. Efficiency of precipitation depended on the soil surface maintaining system. In case of soil maintained as a chemical fallow the highest efficiency was recorded for rains of intensity 2-10 mm h-1. Medium intensity rains (2-5 mm h-1) were least efficient for soil covered with wood chip mulch. In case of stormy rains (>10 mm h-1) a higher increase in moisture was recorded in plots with mulched soil surface compared to control ones (without mulching). Precipitation efficiency also depended on initial soil moisture. Precipitation efficiency was decreasing, along with the soil moisture increase.