Effects of mono- and mixed culture on crude protein content of Medicago sativa L. and Bromus tomentellus Boiss. and on some soil elements

A field experiment was conducted to investigate the effects of mono and mixed culture on crude protein contents of Medicago sativa L. and Bromus tomentellus Boiss, total nitrogen, available phosphorus and potassium of soil using factorial experiment based on completely randomized design with 5 replications. Treatments consisted of three crop compositions (M. sativa, B. tomentellus or mixture of the two), three density levels (low (4 rows, row spacing 70 cm), Medium (8 rows, row spacing 30 cm) and high (16 rows, row spacing 14 cm). Results demonstrated that the forage crude protein in mixed culture was significantly higher than in monoculture of B. tomentellus (p 0.05). Percentage of plant crude protein decreased with increasing plant density both in monoculture and mixed culture. Medicago sativa monoculture and mixed culture increased soil fertility that confirms the importance of forage legumes in forage quality maintenance and preservation of soil fertility. According to the results, mixed culture of M. sativa and B. tomentellus with 8 rows density (30 cm row spacing) is recommended in dryland fields of Fereydoon-Shahr and similar areas.