Effects of mulching on the productivity of lettuce (Lactuca sativa L.) in open field summer production

The production of lettuce in the open field during summer is still much lower than that during spring and winter. Given that there are lettuce cultivars that are resistant to sprouting and form heads even at higher temperatures, this type of production is a good basis for the presence of fresh lettuce in the market during summer period as well. At the same time, the use of mulch in field production has become standard practice. Therefore, this study aimed to examine whether mulch influences the productive characteristics of lettuce grown in open fields. Plastic mulch, wheat straw, and two lettuce cultivars (Radian F1 and Vignola F1), intended for summer production, were used. The plant (rosette) weight, relative leaf water content, leaf chlorophyll content and average nitrate content were examined. Statistically significant differences were observed between the cultivars, and mulch treatments for all tested parameters. The highest average rosette weight was measured for black foil, whereas the lowest average weight was measured for wheat straw. The relative water content (RWC) was the lowest in the control (74.091%), whereas the highest average RWC was recorded in wheat straw and black foil (96.86%). In addition, Radian F1 plants on black foil had the highest average total chlorophyll (40.65 SPAD), whereas the lowest average chlorophyll values were recorded for Vignola F1 in the control (25.723 SPAD). The average nitrate content in the lettuce leaves ranged from 140 to 860 ppm.