Effect of plant residues and Eisenia fetida earthworms on lettuce productivity

Abstract

Current trends for increased crop production and, consequently, increased volumes of plant residues require studying the possibility of combining organic waste mineralization and obtaining agricultural yield. The aim of the study was to evaluate the productivity of lettuce in microcosms depending on the applied plant residues in the peat substrate and the presence of Eisenia fetida earthworms in microcosms. Experiments were conducted under laboratory-controlled conditions (temperature, moisture, light intensity and photoperiod). Microcosms were containers (2000 ml volume) with peat (800 grams), into which plant residues (7%) were applied, along with initial populations of Eisenia fetida earthworms (twelve psc. per microcosm). Parameters of plant development, lettuce yield, earthworm populations and CO₂ emissions from the substrate surface were assessed in the experiment. It was discovered that applying plant residues such as wheat straw, potato tops and cabbage leaves, as well as E. fetida earthworms into microcosms increased lettuce productivity. Application of plant residues and earthworms simultaneously during lettuce growth did not substantially decrease plant system productivity. Acceleration of plant residue mineralization in the presence of earthworms was observed due to increased CO₂ emissions from substrate surfaces with earthworms. The highest lettuce productivity, an increase in earthworm populations and the production of vermicast were achieved in microcosms with application of potato and cabbage residues in peat substrate.