STUDY OF DEGRADABLE MATERIALS FOR SOIL MULCHING IN GREENHOUSE-GROWN LETTUCE

The benefits associated with use of plastic mulches include higher yields, earlier harvests, improved weed control and increased efficiency in the use of water and fertilizers. However, the plastic has a negative effect on the environment. After the crop is picked, the plastic waste must be removed from the field. In the last few years, the use of starch-based biodegradable and oxo-biodegradable films have been introduced as an alternative to conventional mulches. These materials can be incorporated into the soil at the end of the crop season and undergo biodegradation by soil microorganisms. A year study was conducted to determine the response of a lettuce crop to six mulch materials (2 low density polyethylene films (LDPE), 2 oxo-biodegradable and 2 biodegradable) in a greenhouse in South East Spain. Harvest was carried out 45 days after transplanting and the following variables were determined: fresh and dry weight of the aerial part, number of leaves per plant, plant height and the longitudinal and transverse diameters of the plant. Biodegradable and oxo-biodegradable films showed an agronomic behaviour equal to LDPE. The degradation time of oxo-biodegradable films was longer than biodegradable films. The evaluation of the performance in the field showed that the biodegradable films are as suitable for protected cultivation as LDPE.