Simulation of the increase in values and the frequency of precipitation deficiencies for cultivated crops have been carried out for the growing season (April– October). This simulation pertains to the Podkarpackie Province and takes into account following temperature increase scenarios: 1, 2 and 3oC. In this paper the agro-technical level was assumed for the end of the 20th century and sums and precipitation structure was assumed for the long-term period 1901–2000. The agricultural efficiency of precipitation was established using the multi-step regression analysis. This procedure was initiated in order to determine the dependency for dampness of the cover soil in reference to air temperature and precipitation. This study indicates that precipitation frequency during growing season along with precipitation deficiency will increase from 39% (during the period 1901– –2000) to 59, 76 and 92% respectively when we consider the above-mentioned temperature scenarios. There is a 5% probability of the increase of precipitation deficiencies during the period 1901–2000. Precipitation deficiencies will increase scenarios. ...
The yield of the spring cereals depends mainly on the distribution of at-mospheric precipitation in the growing season according totheir requirements in particular growing stages. Both precipitation excess and deficiency are not de-sirable. The analysis of spring cereals' water requirements fulfillment was made on the basis of IMGW data concerning the sums of atmospheric precipitation in Siedlce in the years 1968-1997. Monthly sums of precipitation were compared with optimum values of precipitation, estimated by Klatt (Water needs..., 1989),for specific spring cerealsin particular vegetation months. The characteristics of water requirements fulfillment for particular cereals was made on the basis of differences between the values of monthly sums of precipitation during the years analyzed and the values considered as optimum. In the months of April, May and June the frequency of precipitation deficiencies was higher than the frequency of precipitation excesses for all the cereals analyzed. However, in July precipitation excesses have been registered more frequently than the deficiencies. During the analyzed thirty years, the highest values of the average precipitation deficiencies for all the spring cereals were registered in May, while the values of precipitation excesses - in July. Meteorological growing season during the analyzed years began on 30th March and ...
