Effect of calcium foliar application on some fruit quality characteristics of ‘Sinap Orlovskij’ apple
¹Lithuanian Institute of Horticulture, Kauno 30, LT-54333 Babtai, Kaunas distr., Lithuania; e-mail: email@example.com
²Lithuanian Institute of Horticulture, Kauno 30, LT-54333 Babtai, Kaunas distr., Lithuania;e-mail: firstname.lastname@example.org
Effect of calcium fertiliser sprays on eight-ten-year-old apple trees of the cv. ‘Sinap Orlovskij’ on rootstock 62-396 was investigated at the Lithuanian Institute of Horticulture in 2001–2003. Calcium chloride, calcium nitrate, liquid experimental calcium fertilisers and Wuxal Calcium were used. Calcium chloride was applied twice at the time close to harvest (total CaO rate – 5.9 kg ha-1). Other fertilisers were used fivefold from the beginning of June (total CaO rate – 6 kg ha-1) in the combination of two sprays with calcium chloride (CaO rate – 5.9 kg/ha-1). The most significant effect of calcium fertilisers on fruit calcium content was found in 2003. When fertilisers were applied sevenfold, fruit calcium increased by 50–120 mg/kg of dry fruit weight in comparison with the control. The most unfavourable for calcium accumulation was the warm and dry weather in year 2002. Apples contained only 170–230 mg of calcium per kg of fruit dry matter and bitter pit affected up to 35% of apples. In years 2001 and 2003 fruit calcium content was 300–330 and 340–460 mg/kg, respectively, bitter pit affected up to 2% of apples. Sevenfold applied calcium fertilisers decreased bitter pit incidence about twice in comparison with the control and two applications of calcium chloride. All tested fertilisers had a similar effect on bitter pit reduction. Calcium fertilisers had not a consistent effect on fruit flesh firmness, soluble solids content and natural weight loss.