N. Poushkarov Institute of Soil Science, BG-1080 Sofia, Bulgaria
VARLEV, I., 2004. Risk evaluation of drought under rainfed maize in Bulgaria Bulg. J. Agric. Sci., 10: 113-116
Drought consequences are severe and frequent under rainfed maize. Economic risk evaluated by the proposed criteria "critical yield". Critical yield is defined as a ratio of production cost C and market price of harvested production Pyeld. Economical losses happen over the years (in %) when the yield is lower than the critical one
Long term data (13-18 years) from 15 experimental farms have been analyzed. It is established that the risk of maize cultivation on drylands in North Bulgaria seldom surpasses 10% of the years. Economical losses in South Bulgaria cover from 20 to 70% of the years. Only on soils of high water holding capacity the risk is near to 20%. Obtained results show that the cultivation of rainfed maize in South Bulgaria is related to significant risk.
If the risk criterion is higher, for instance a granted minimal profit of 100 lv/ha.year, the risk augments about 10% above the specified values.