Effects of fertilization and climatic factors in a long-term experiment with blackcurrant (Ribes nigrumL.) cv. Ben Tron

Abstract

Two-year-old blackcurrant plants cv. Ben Tron were planted in 1991 to investigate long-term effects of seven fertilization strategies. Broadcast fertilization was given in spring and autumn, fertigation from May until August, or a combination of fertigation and broadcast fertilization. Three fertilizer rates were used, and the amount was increased three times during the trial because of low mineral content in the leaves and insignificant yield response. Yield parameters, macro nutrient content in leaves and content of soluble solids in fruit juice were recorded over 11 years. The variation between years was significant for all parameters recorded, but the fertilization strategies had only a minor effect over time. Content of macro nutrients in leaves was low compared to recommended values, and did not respond significantly to increasing fertilizer amounts. Yield decreased with plant age. Frost reduced yield in at least two years, but few significant correlations with precipitation and temperature were found. A good water access seems to be important for a stable fruit yield, while precipitation during flowering is likely to reduce yield because of fruit drop.