REGULATED DEFICIT DRIP IRRIGATION IMPACT ON THE YIELD OF THE 'LYULIN' PRffiOCANE-FRUITING RASPBERRY CULTIVAR

摘要

The problem of water scarcity deepens all over the world, the agriculture accounting for more than 70% of the total consumption. The use of irrigation water can be decreased with the introduction of more efficient methods (microirrigation) and technologies (Regulated Deficit Irrigation, RDI). Both approaches were subjected to a nine-year investigation together with the 'Lyulin' primocane-fruiting cultivar. The raspberry crop was chosen because of its good positions on the international market and theshort time for the investments to payback. The water application rates during the main phenophases - intensive growth, blossom, and fruit ripening - equaled 100%, 75% and 50% of the crop evapotranspiration. The yield varied considerably according to both the meteorological conditions during the vegetation and the health status of the plantation. The average yield for the nine-year study period was in the range of 8575-11218 kg ha~(-1), depending on the degree of the application rates reduction; the maximum of 16429 kg ha"1 was recorded in the forth vegetation. From the seventh to the tenth vegetation. - yields significantly declined due to progressing viral infections. Compared to the control, only the maximum reduction of irrigation resulted in significant yield decrease. In most variants and years, one cubic meter of water was needed to produce about 2.0 kg of raspberry fruit.