The rainfall use efficiency and soybean grain yield under rainfed conditions in Vojvodina

Rainfall is one of the most important environmental factors influencing crop production under dry land farming conditions. In the Republic of Serbia, the soybean is produced under rainfed conditions, and therefore online monitoring of the rainfall use efficiency (RUE) is essential for efficient management of production. The research aim was to estimate the effects of amount rainfall during the growing season (RGS) and average monthly rainfall on soybean grain yield (GY) in the Vojvodina during the sixteen year period (2000-2015). Distributions of RGS were not satisfactory and negatively influenced the expression genetic yield potential of cultivars. Rainfall deficits during the growing season limited the soybean plant reproductive growth stages leading to GY loss. The coefficient of variation indicated that RGS and monthly rainfall changed moderately from year to year. Regression equations showed that GY tended to increase with the amount of rainfall. GY had strong positive relationship with RGS and rainfall in May, July and August. Since the amount and distribution of rainfall during growing season are critical determinants of GY, soybean cultivars of shorter vegetation periods should be developed and cultivated so that maximum utilization of rainfall is ensured