Opady atmosferyczne w okolicy Lublina a potrzeby opadowe roślin uprawnych

Abstrakt

The present paper characterizes the degree of providing for the rainfall needs for 12 cultivable plant species: spring barley, oats, spring wheat, winter wheat, winter rye, faba bean, pea, red clover, alfalfa, yellow lupine, sugar beet, fodder beet, potato-late, potato-early, and winter rape. 10 days's water needs of plants were compared with the amount of atmospheric precipitation sums recorded in the Agrometeorological Observatory in Felin near Lublin, managed by the Department of Agrometeorology of the Agricultural University of Lublin. Rainfalls were measured at 1 m height above the ground surface with the Hellmann's rain gauge. Mean precipitation sums were analyzed from the 1^st 10 days of April till the 2^nd 10 days of October in the years 1951-2000. The highest mean rainfall sum (29 mm) occurred on the 3^rd 10 days of July, the lowest rainfall (12.3 mm) occurred two times: on the 2^nd 10 days of April and the 3^rd 10 days of October. Temporal variability of the 10 day's rainfall sums was the greatest in October, while in May it was the lowest. Significant differences between 10 day's rainfall needs of plants and the rainfall sums were estimated with the Student t test. The study period, i.e. 1951-2000 was sectioned into 10-year intervals and temporal variation of the phenomenon discussed was analyzed. Mean rainfall sums from the entire period appeared too small as compared with the rainfall needs of all the considered plants. In the whole 50-year period, the most favorable conditions as far as water needs are concerned were found for cereals, somewhat worse in case of root crops, followed by papilionaceous, while the worst was among oil plants. In successive ten-year periods the highest rainfall sum occurred in the years 1971-1980, and the lowest in the following period, i.e. 1981-1990. Such differentiation affected the number of statistically significant rainfall deficits in those periods. It the period 1971-1980 they constituted 12.5% of all the data, while in 1981-1990 they reached 40.0% of the data. In the whole study period (1951-2000) the rainfall water deficits most often occurred in the 2^nd 10 days' period of June and in the 1^st of July. These might appear unfavorable for root crops. Basing on the analysis of successive ten-year periods, it can be stated that water deficits most often occurred both in the 2^nd and the 3^rd
10 days' periods of May and June.