干旱区生态环境知识资源中心

The experiment was carried out from May to September 2002, at the Federal University of the Semi-Arid Tropic in Mossoro-RN, to evaluate the performance of carrot-lettuce intercropping systems by means of agronomic criteria, economic (profit margin) indicators, and yield efficiency (assessed through Data Envelopment Analysis models - DEA). We also used the ordinal multicriteria methods of Borda, Condorcet, and Copeland to aggregate information to all criteria and to identify the best treatments. The experimental design was randomized complete blocks, in a 3 (sole crop, three carrot rows alternate with three lettuce rows - 3F, and four carrot rows alternate with four lettuce rows - 4F) x 4 (crisp head lettuce cultivars: Lucy Brown, Taina, Laurel, and Mesa 659) factorial scheme, with four replications. In each block, carrot was grown as sole crop. Agroeconomic indicators, such as land equivalent ratio - LER - and profit margin, yield efficiency of intercropping systems by DEA models, were assessed. A univariate analysis of variance in a 2 x 4 + I factorial scheme (treatments from two intercropping systems versus four crisp head lettuce cultivars, plus carrot in sole crop) was used to assess all indicators. LER of intercropping systems were significantly higher as compared to that of sole crop, with the efficiency of intercropping systems varying from 90 (Carrot + Taina - 4F) to 133% (Carrot + Mesa 659 - 4F). There was no significant difference in the profit margin between sole crop and intercropping systems. A significant interaction was observed between cropping systems and lettuce cultivars for yield efficiency by DEA. According to the ranks of ordinal multicriteria methods, the best intercropping systems were carrot + Mesa 659 (4F), carrot + Laurel (3 R) and carrot + Mesa 659 (4R). The yield efficiency by DEA and the ordering of ranks based on ordinal multicriteria methods were more efficient than the agroeconomic indicators for discriminating the intercropping systems performance.