摘要 : In 2 cycles of production, lettuce cultivars Iceberg (cycle 1) and Cambria (cycle 2) were grown in plastic tunnels in Pontecagnano, near Salerno, Italy, from September 2001 to March 2002. The soil of individual plots had previousl... 展开 In 2 cycles of production, lettuce cultivars Iceberg (cycle 1) and Cambria (cycle 2) were grown in plastic tunnels in Pontecagnano, near Salerno, Italy, from September 2001 to March 2002. The soil of individual plots had previously been fertilized with 2 types of organic amendment (A and B, obtained from vermiculture), mineral fertilizers or none (control). Before the start of the 2nd cycle, the plots previously treated with organic amendments A and B were further treated with olive husk compost at30 and 60 t/ha, respectively. In both production cycles, growth rates of lettuce plants in the organic plots were equal to or higher than those of plants grown under mineral (100-150 kg N/ha) fertilization. Yields of marketable heads in the first cyclewere higher in the 2 organic plots (51 and 60 t/ha) than in the mineral fertilizer (36 t/ha) or control (30 t/ha) plots, while in the second cycle the organic and mineral fertilizer plot yields were the same. Plants from the organic plots had the highestnitrate contents on a dry matter basis, but thanks to their higher water content, nitrate contents were equivalent to those of plants from mineral fertilizer and control plots on a fresh matter basis. 收起