INFLUENCE OF SUBSTRATE TYPES AND WAYS TO ADJUST THEIR AGROCHEMICAL PROPERTIES FOR BIOMETRIC PARAMETERS OF SWEET PEPPER SEEDLINGS

Abstract

There are some problems of growing plants on pure vermiculite and mineral wool substrates in sheltered ground. It is suggested that the problems arise due to alkalization of substrates. The article presents results of the studies on the influence of preparation methods of peat and vermiculite substrates on biometric parameters of sweet pepper seedlings. The research was carried out in a vegetative experiment established in 2017–2019 in the scientific laboratory of Agrarian Institute of Mordovian State University named after N. P. Ogaryov. Two substrates and four ways of adjustment to their agrochemical properties were studied: 1) watering with a nutrient solution with 5.0 pH; 2) preliminary phosphating of the substrate, followed by watering with a nutrient solution with a pH of 5.0; 3) watering with a nutrient solution with a pH of 4.0; 4) application of nutrients into the soil in reserve, followed by irrigation with tap water with a pH of 5.0. Seedlings were grown in a vegetation chamber with adjustable parameters: daytime air temperature +24...+26, at night + 18...+20 degrees Celsius, illumination - 7 klx. A hydroponic solution was used (modified medium for tomatoes according to Aliev E.A.). Watering was carried out by the method of drainage flooding. It was found that the peat substrate provided the best development of seedlings - the plants were characterized by a greater wet weight (+4.91 g), height (+14 cm), leaf area (+148.1 square centimeters). High alkalization of vermiculite substrate from pH 5.95 to 8.14 was revealed. Better growth of sweet pepper seedlings was ensured by constant acidification of the nutrient solution to 4.0 pH, as well as preliminary phosphating of the substrate and subsequent cultivation at 5.0 pH of the nutrient solution. Preliminary phosphating of the vermiculite substrate resulted in an increase of leaf area by 115.5 square cm, wet biomass - by 5.38 g. Acidifying of the nutrient solution to 4.0 pH had a similar beneficial effect on pepper seedling growth.