Mineral Composition of ‘Conference’ Pears as Affected by Different Foliar Sprays
M. Gąstoł1, I. Domagała-Świątkiewicz2
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1Department of Pomology and Apiculture 2Department of Soil Cultivation and Fertilization, Agricultural University, Al. 29 Listopada 54, 31-425 Kraków, Poland
Pol. J. Environ. Stud. 2009;18(4):741–744
The aim of our two-year study (2004-05) was to assess the effects of different foliar fertilizers (calcium chloride, Kalcisal, Kalcisal+Kalcifos and Sanisal) on fruit mineral content. The paper also presents the distribution of some macronutrients (N, K, Mg and Ca) in different parts of ‘Conference’ pears. The treatments consisted of five foliar sprays (at the rate of 0.17% Ca) in two week intervals followed by five (at the rate of 0.35% Ca) in one-week intervals. After 120 days of storage, fruits from the treatments were divided into: peel, calyx end, basal end, and outer part of flesh. Each of them was analyzed to assess the contents of nitrogen, potassium, magnesium and calcium. The mineral content of investigated fruits was strongly affected by fertilizers used as well as by the season. Fruits from non-treated trees contained the lowest amounts of macronutrients (average data of four fruit parts). The higher amounts of potassium, magnesium and calcium was found in 2004. In 2004 the highest concentration of calcium was proved for fruits sprayed with Kalcisal (125.5 mg Ca kg-1 f.w.), and in 2005 for calcium chloride (101.3 mg kg-1 f.w.). The K/Ca ratio varied from 16 to 35 and 21 to 35 for 2004 and 2005, respectively. As far as K/Ca ratio is concerned, no significant differences between pears sprayed with CaCl2 or Kalcisal in comparison to control was found. On the contrary, in both years of the study, the higher K/Ca ratio for Kalcisal+Kalcifos and Sanisal treatments was noted. Sanisal and Kalcisal+Kalcifos significantly increased N/Ca fruit ratio in 2005, as well as Mg/Ca ratio in all seasons. An analysis of average data for all treatments revealed the highest concentration of investigated macroelements in the peel of fruits. The lowest calcium accumulation was recorded in samples taken near the calyx, and in the outer part of the flesh. The lowest N/Ca, K/Ca and Mg/Ca fruit ratios were investigated for peel, whereas the highest – near the calyx end.