Effects of Mixed and Row Intercropping on Yield and Quality Traits of Alfalfa and Three Grass Species in Rainfed Areas of Northern Khorasan, Iran

Strong benefits of species diversity have been demonstrated in mixed cropping on rangelands. In order to determine the best composition of mixed cropping of alfalfa (Medicago sativa) with three cool season grass species (Agropyron elongatum, Agropyron desertorum and Festuca arundinacea), on yield and quality traits, an experiment was conducted during two years (2009 and 2010) in Bojnourd, Iran. The used experimental design was a split plot based on randomized complete block design with three replications. Main factor was different compositions of alfalfa and grasses and sub factor were two intercropping methods (Mixed intercropping and Row intercropping). Dry matter (DM) yield, Land Equivalent Ratio (LER) and quality traits including Crude Protein (CP), Water Soluble Carbohydrates (WSC), Dry Matter Digestibility (DMD) and Acid Detergent Fiber (ADF) were determined. Results showed that the effects of treatments were significant for all of traits. The highest DM yield was obtained in mixed intercropping ratio of alfalfa 25% +A.elongatum 75% (2317 kg.ha-1) that increased 23.3% compared with alfalfa monoculture treatment. The effects of cropping method were significant for all of traits. The highest CP was obtained by mixed intercropping of alfalfa 75% + Festuca 25% (14.51%). In conclusion, mixed intercropping of alfalfa and Festuca arundinacea produced moderate DM yield coupled with higher quality traits. Whereas, mixed intercropping of alfalfa and A. elongatum produced highest DM yield but lower forage quality.