The experiment was conducted in 2025 in the greenhouse of the Institute for Vegetables Crops Smederevska Palanka on slightly acidic soil (pH 5.77 in KCl), with a low humus content (2.13%) and high levels of available phosphorus and potassium. The aim was to examine the effects of soil amendment and foliar calcium treatment on chlorophyll content in the leaves of the pepper variety Dora. Four treatments with 15 plants each were set up: control (no soil amendment and no calcium application), foliar calcium treatment (every 5–7 days), soil amendment (calcium-magnesium fertiliser, pelleted manure 5 kg/are, zeolite 500 kg/ha) without foliar calcium, and a combination of soil amendment + foliar calcium. Chlorophyll content was measured during the fruit-setting phase using a SPAD meter at three sites per leaf on three plants per replication. High temperatures prevailed during the growing season (average June–August 29.8–31.2 °C). Analysis of variance (ANOVA) and Tukey's HSD test showed a statistically significant effect of soil amendment factors (PM + zeolite) on chlorophyll content (p<0.05 and p<0.01). The highest values were recorded in the combined treatment, repair + foliar Ca treatment - 94.4 SPAD, followed by the treatment with only soil repair - 91.4 SPAD. Treatments without soil amendment, with or without foliar calcium treatment, had significantly lower values of 83.7 (without foliar Ca application)– 85.2 SPAD (with foliar Ca treatment). The results indicate that soil amendment with organic fertiliser and zeolite positively affects chlorophyll content. At the same time, foliar calcium treatment further enhances this effect under high temperatures and weakly acidic soil conditions.
Stojiljković et al. (Thu,) studied this question.
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