Effect of condit soil improver on growth, yield and leaf mineral content of two summer pear cvs. with interstocks

The study involving 2 pear cultivars was conducted in 2006–2016. ‘Radana’ and ‘Clapp’s Favourite’ were planted in the spring 2006 in the Experimental Station next to Wrocław (south-western Poland) on Quince S1 and Caucasian pear seedlings with 2 interstocks – ‘Doyenne du Comice’ and ‘Pyrodwarf’. An annual dose of 3 tonnes per hectare of Condit Basic bio-fertilizer was applied onto the tree row soil surface at the beginning of March 2012, i.e., starting from the 7th year after the planting. The study objective was to evaluate effect of Condit preparation on summer pear tree cultivars which are not compatible with Quince, and to assess interstock suitability in their context. The yields obtained in the first eleven years following tree planting were the most abundant for ‘Radana’ on Caucasian pear and on Quince with ‘Doyenne du Comice’ interstock. When applied for 5 years, Condit increased the leaf surface area, however a significant difference was exhibited only by ‘Radana’ on the Caucasian pear. This soil improver did not affect tree growth and yielding; total chlorophyll content; foliar Mg, P, Ca, and K; and mean fruit mass across the investigated treatment combinations.