Summary:

On the basis of research done in the Department and literature data, indices
of optimal precipitation and water needs of selected crops (cereals, root plants
and papilionaceae) have been determined. It was found that both insufficient and
excessive precipitation affected yield adversely. It caused the following decreases
in yields: cereals 2-27 and 3-21%, potato 4-45 and 3-30%, sugar beetroot 2-43
and 14-19%, fodder beet 16-73 and 8-28%, legumes 5-42 and 21-40%, and papilionaceae
3-34%, respectively.Productivity of 1 mm water from precipitation was higher compared with
productivity induced by sprinkling. The calculated index of productivity for water
from sprinkling relative to water from precipitation was in the range 40-90%.
Sprinkling increased the yield of winter wheat and spring barley by 20%,
spring wheat by 25%, potato 47 and 55%, and sugar beet 10-40%.