engleski

Autumn lettuce production on rockwool slabs

A trial was carried out to determine the possibility of re-using of rockwool slabs after tomato production. Lettuce was the second crop suitable for autumn production in unheated greenhouse because of short cycle. In trial, seedlings of four iceberg lettuce cultivars were planted on rockwool slabs in September. Plants were fertigated with nutrient solution according to Tesi. Spacing between plants on rockwool slab was 0.25 m. Space between rockwool slabs was 1.2 m. Every 10 days during the lettuce growing period there were samplings for vegetative growth and dry matter measuring. During harvest, total head weight, diameter, height and marketable yield were determined. Between number of leaves and head weight positive correlations were determined (from 0.6583 to 0.8397). Negative correlations were determined between head weight and dry matter content (from -0.574 to -0.9622). Single harvest was done 47 days after planting. The highest total head weight (241 g) and marketable weight (222 g) was achieved by cv. Triathlon. Marketable yield of the other cultivars was from 13.5 to 32.4 % less. Diameter of marketable head varied from 18.9 to 23.5 cm depending on cultivar. Cultivar Triathlon had the highest heads (20.4 cm) while other cultivars had statistically lower heads (from 17.2 to 18.2 cm). It is possible to grow lettuce without heating during autumn season in continental part of Croatia. Regardless to low yield achieved (from 495 to 733 g m-2) growing period in unheated greenhouses is prolonged with lettuce cultivation.

Lactuca sativa L.; soilless culture; rockwool; yield

nije evidentirano