Agriculturae Conspectus Scientificus, Vol 87, No 2 (2022)

Improving Yield and Quality-Related Physiological Characteristics of Lettuce by Integrated Inorganic and Organic Fertilizers Management

Elisaveta Bogomolova KIROVA, Maria Prokopova GENEVA, Kostadin KOSTADINOV, Stoyan FILIPOV

Pages: 127-134


The research aims to obtain more information on the nitrogen metabolism and nutraceutical properties of two types Lactuca sativa L. var. crispa L. type Batavia cv. 'Maritima' and type Lollo Rosso cv. 'Tuska' and one type Lactuca sativa L. var. capitata L. cv. 'Winter butterhead' under the implementation of different organic fertilizers. In this respect, the main goal of our study is to define a proper macro- and micronutrients source which has the most beneficial effect on yield as well as on various quality parameters of lettuce. The experiment was conducted in an unheated greenhouse in two consecutive seasons (2018/2019 and 2019/2020) under all the requirements for organic production. Four organic fertilizers (Italpollina”, “Arcobaleno”, “Lumbrical” and “EKOprop” were studied. From obtained results, it could be concluded that the impact of fertilizers on lettuce growth and quality has possessed cultivar dependence. The fertilizing with natural fertilizers, so that the nutrients they possess are strictly comprised of animal-based materials (dry bird manure “Italpolina”, mix from bovine, horse and chicken manure “Arkobaleno”) or compost (lumbricompost made by Red Californian worms “Lumbrical”) of the three lettuce cultivars resulted in lower plant FW and yield, compared with NPK fertilizing. Only fertilizing with a mix of different beneficial microorganisms leads to the same plant FW and yield as fertilizing with inorganic fertilizer. Based on the higher plant FW and yield of all three lettuce cultivars the treatment with the fertilizer composed with beneficial microorganisms can be substituted with the treatment with inorganic NPC fertilizer. “EKOprop” fertilizing showed the lowest leaf nitrate concentration which correlated with higher activity of nitrogen assimilating enzyme nitrate reductase.


nitrate reductase, glutamine synthetase, Lactuca sativa L. var. crispa L.; Lactuca sativa L. var. capitata L., organic fertilizers

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