European Conference on Crop Diversification September 18-21 September 2019, Budapest, Hungary Evaluation of the Land Equivalent Ratio index in barley-pea and bread wheat-faba bean intercropping Tavoletti S*±1. F. Straccia1, A. Merletti1, L. Iommarini1 1 Dipartimento di Scienza Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona – Italy ∗ Speaker ± Corresponding author: s.tavoletti@univpm.it 1 Introduction To improve agricultural sustainability, a valuable strategy could be the increase of biodiversity of cultivated fields through intercropping (Bedoussac et al., 2015; Brooker et al., 2015; Yu et al., 2016). Cereal-legume intercropping exploits the complementarity between these two groups of crops. In 2017, a field trial showed that the Mix1(50-50) was not effective because barley was too much competitive against pea, and faba bean plant density could have been increased. In the present research, new barley-pea and bread wheat-faba bean combinations were evaluated to increase the Land Equivalent Ratio (LER) and to reduce weed competition in mixed vs sole legume crops. 2 Materials and Methods 2.1 Trial 1- WP2 Barley-Pea trial: conventional farming – no herbicide treatments. At the UNIVPM Experimental Station a split-plot design (4 replicates, sub-plot size 9x1.2m2) was performed including one barley (Tea) and two pea (Hardy, Astronaute) varieties as sole crops and mixed crops: Mix1(50-50), Mix2(33-67), Mix3(25-75), Mix4(20-80). Nitrogen fertilization (whole-plots) was applied as shown in Table 1, amount of N in mixed crops being proportional to the barley seed density. The trial was sown on February 1st, 2018, and harvested on July 3rd, 2018. Table 1. Trial 1: Nitrogen fertilization plan (N kg/ha). Pea sole Barley sole Mix1 (50:50) Mix2 (33-67) Mix3 (25-75) Mix4 (20-80) High N 20.0 80.0 40.0 26.4 20.0 16.8 Low N 0.0 40.0 20.0 13.2 10.0 8.4 2.2 Trials 2 and 3 –WP4 Barley-Pea trials: organic farming – no nitrogen fertilization. Two trials were performed with participatory farmers at 2 locations: Monte San Martino – MC (Trial 2) and Sterpeti - PU (Trial 3). At each site, a randomized complete block (4 replicates) was applied (Plot size: 50x4.5m2 for Trial 1 and 50x4.2m2 for Trial 2. One barley (Tea) and one pea (Hardy) varieties were included as sole crops and as Mix2(33-67) and Mix3(25-75). Trials were sown on Jannuary 26th, 2018 (Trial2) and March 28th, 2018 (Trial3), and harvested on July 3rd, 2018 (Trial2) and July 9th, 2018 (Trial3). 2.3 Trial 4 – WP4 bread wheat-faba bean trial: organic farming. The trial was performed at Rocca Priora – AN as a randomized complete block design (3 replicates, plot size 10x1.2m2). Three bread wheat (ACA320, Bologna, Marcopolo) and two faba bean (Chiaro di Torre Lama, Prothabat69) varieties were evaluated as sole crops and as Mix1(50-50), Mix2(50-65), Mix3(50-80), Mix4(33-75) and Mix5(33-80). The trial was sown on January 31st, 2018 and harvested on July 19th, 2018. 3 Results 3.1 Trial 1: Barley-Pea In mixed crops, LERbarley was always much higher and LERpea was always much lower than expected (Table 2). Even though LERtotal was always higher than 1, Mix1 showed the highest values because of the high yielding ability of barley in mixed crop combinations. As frequently observed in mixed cropping trials, the LERtotal values were higher at low than at high nitrogen fertilization levels.