Drought and its relation to field crops production in [the] Vojvodina Province [Serbia, Serbia&Montenegro]

In order to perform an analysis of drought and its relationship to field crops production in the Vojvodina Province (Serbia, Serbia&Montenegro), we adapted the Hergreaves' (1992) procedure and calculated the moisture supply indexes, which are the quotient of monthly precipitation and average plant water requirements. The indexes showed drought to be the predominant type of summer weather in the province. Of the 39 years analyzed in the study, one was arid and 20 semiarid, or extremely droughty and droughty, respectively. Added to this were 12 semihumid, or moderately droughty, years. Only six of the 39 years had no precipitation deficits. Overall, 80% of the summer had smaller of larger water deficits relative to water amounts needed fos successful crop production, Twenty-two percent of the summer was extremely droughty, or arid, and 32% droughty, or semiarid, while 26% of the season had enough water. These three types of weather followed each other without any regularity what so ever. The yields of maize, sugar beet and soybean sown in the spring varied according to the amount and distribution of precipitation, but sunflower yields did not, the reason being the specific nature of this crop. Either highly significant or significant correlations between yield and precipitation were observed in the case of maize, sugar beet and soybean, whereas with sunflower the correlation was positive but not statistically significant. The maize, sugar beet and sunflower yields were low, far below these crops potential for yield and more than 50% lower than yields that could have been obtained in irrigated conditions. The yields also varied widely from year to year and very high yield variation coefficients were determined. Analyses have shown that both severe droughts and extremely moist years may be expected in the upcoming period as well as subperiods within a single year with more or less precipitation than what has been recorded in the past. This may be attributed to the global climatic change, the effects of which are manifested in Vojvodina as well.