Investigation of yield and some traits of wheat and weeds in intercropping with chickpea under nitrogen management in rainfed condition

Intercropping is known to improve the utilizing resources and increasing yield and yield stability as compare with monoculture. To evaluate wheat-chickpea intercropping، an experiment in factorial split plot based on randomized complete block design with three replications was carried out in Dryland Agricultural Research Institute، Sararoud، Kermanshah، Iran، during two years (2008-10). Two factors، N fertilizer in three levels (1. No fertilizer; 2. 60 kg. ha-1 urea for wheat and 20 kg. ha-1 for chickpea and 3. Nitragin as a biofertilizer + 30 kg. ha-1 urea for wheat and no urea for chickpea) and weed control in two levels (no weeding and weeding) were placed as factorial in main plots. In the sub-plots were also placed ten intercropping patterns including: 1. Wheat monoculture، 2. Chickpea monoculture، 3. Mixed-row intercropping with 1:1 ratio of wheat: chickpea، 4. Mixed-row intercropping with 2:1 ratio of wheat: chickpea، 5. Row intercropping with 1:1 ratio of wheat: chickpea، 6. Strip intercropping with 2:5: 1:5 ratio of chickpea: wheat: chickpea: wheat، 7. Strip intercropping with 2:7 ratio of chickpea: wheat، 8. Strip intercropping with 7:2 ratio of chickpea: wheat، 9. Strip intercropping with 4:9 ratio of chickpea: wheat and 10. Strip intercropping with 9:4 ratio of chickpea: wheat. Results showed that number of grain per spike، number of spike per m2، grain yield، plant height، biological yield and harvest index of wheat were affected by inter-specific competition (cropping pattern)، year and their interaction effect. Wheat had higher competition ability to uptake and use the resource than chickpea. Strip intercropping patterns with lower width of the wheat strip and more width of chickpea strip (patterns 8 and 10) and row intercropping (pattern 5) were better than the wheat monoculture in most studied traits like plant height in first year، biological and grain yield، harvest index and light absorption. The row intercropping in second year reduced weed biomass in chickpea which not only was superior to monoculture، but it can be used as an approach to weed control in chickpea