Combined Effect of Chlorella vulgaris Beijer. (Chlorophyta) and Silicon-Containing Organic Fertilizer on Bell Pepper Productivity, Microbiocenosis, Allelopathic and Agronomic Soil Characteristics

Abstract

The combined effect of the culture medium of green microalgae (<i>Chlorella vulgaris</i>) and organosilicon fertilizer (analcite + peat (pH 5.8) in a ratio of 1 : 3) on characteristics of growth, development, photosynthetic productivity, yield and quality of bell pepper (<i>Capsicum annuum</i> L., cv. "Bilozyorka"), as well as microbiocenosis, allelopathic and agronomic characteristics of the soil were studied in pot experiments. The culture medium of microalgae was added at a rate of 10 mL per pot (0.7 L) to sifted and sterile gray podzolid soil. Plants were grown in a phytochamber under controlled conditions of light, temperature and soil moisture. The vitality of pepper plants was assessed by morphometric growth characteristics (shoot height, stem diameter, surface area of leaves, root length, dry weight of shoots and roots, number and weight of fruits), the content of photosynthetic pigments in leaves, and protective antioxidants (carotenoids, flavonoids and anthocyanins) in fruits. At the end of the experiment, the content of phenolic compounds, electrical conductivity, redox potential, pH, content of NH<sub>4</sub><sup>+</sup>, NO<sub>3</sub><sup>-</sup> and HCO<sub>3</sub><sup>-</sup> ions in the soil solution were determined. Eco-trophic groups of soil microorganisms were also determined. A synergistic enhancement of the positive effect of microalgae and organosilicon fertilizer on the growth, development, productivity and fruit quality in bell pepper was established. The combined application of the microalgae with organosilicon fertilizer more effectively improved the agronomic and allelopathic characteristics of the soil, stimulated the development of agronomically useful eco-trophic groups of microorganisms, incresed the intensity of the mineralization and transformation of organic matter compared to the control and treatments in which microalgae or fertilizer were applied separately.