Pure stand and intercropping of lucerne and Agropyron cristatum under dryland farming across five environments of Iran

An experiment was conducted to evaluate intercropping of alfalfa and Agropyron cristatum (crested wheatgrass) in ratios of 33:66%, 50:50%, and 66:33% and pure stand using randomized complete block with three replications under rain-fed conditions across five environments of Iran (Samirom, Brojerd, Bojnord, Damavand and Islam Abad) over two years (2011-2012). The seeds of alfalfa and A. cristatum were determined as 15 and 10 kg/h for the pure stand, respectively. The seeds of mixed cropping were determined based on the replacement method. Seeds were sown in pure stand and alternating rows according to the treatments in October 2010. The forage DM yield was harvested at the flowering stage, and their crude protein (CP) was estimated using NIR. The land equivalent ratio (LER) was measured for forage yield. Results of mean comparisons showed that pure stand alfalfa and (50% alfalfa +50% A. cristatum) with average values of 1840 and 1766 Kg/h (with no significant difference) had the higher forage DM yield over all environments, respectively. The LER ratio in mixed cropping (50% alfalfa, 50% A. cristatum) was equal to the unit in Bojnord and Borujerd and higher than other locations. For CP%, the higher values of 18.12% and 15.30% were obtained in pure stand alfalfa and a mixture of (66% alfalfa +33% A. cristatum), respectively, indicating higher quality of mix copping using more alfalfa ratio. The lowest CP (10.48%) was for the pure stand of A. cristatum species. According to the results, the forage DM yield of pure alfalfa in several cases was higher than its mix cropping with A. cristatum. However, pure stand alfalfa is not recommended for the development of pastures because its fresh forage causes bloat when animals are grazing young and fresh pasture, but mix cropping eliminates this risk and provides a good posture rich in protein. It was concluded that the mixture of (50% alfalfa and +50% A. cristatum) with the intercropping pattern was recommended to rehabilitate low-efficient rangelands and dryland farming systems.