CALCIUM FERTILIZATION IN A KIWIFRUIT ORCHARD

Calcium is an important nutrient associated with fruit quality in kiwifruit; thus, it is desirable to ensure an adequate calcium status. However, Ca availability in acid soils is low and its mobility in kiwifruit plant via phloem is limited. The aim of this study was to determine the efficiency of a commercial biostimulant as Ca fertilizer – foliar and/or soil application - in a kiwifruit orchard in NW Spain (Galicia). In this area, the main kiwifruit producing region of Spain, soils are slightly acidic, and kiwifruit plants showed low plant Ca concentrations that may reduce fruit yield. The fertilizer applied was a biostimulant (9.6% (w/v) CaO), which is recommended to prevent calcium deficiency symptoms resulting from lack of uptake into fruit. We have studied the fertilization effect on the nutrient levels in soils, leaves and fruits, as well as on fruit yield. The results of the present study showed that application of a biostimulant as Ca fertilizer did not increase Ca concentrations in leaves, fruits and soil compared to controls, nor did it affect fruit yield.