Performance of some forage grasses or legumes and their mixtures under dry land conditions

Abstract

An experiment was conducted in order to investigate hay yield and nitrogen harvest in single and binary grass (tall wheat grass ( Agropyron elongatum), creasted wheat grass ( Agropyron cristaturn), and smooth brome grass ( Bromus inermis) mixtures with sainfoin ( Onobrychis sativa) and alfalfa ( Medicago sativa L.)) for 3 years between 1986 and 1989 under dry land conditions in Erzurum, Turkey. The hay yield, nitrogen harvest, protein concentration and land equivalent ratio (LER) in the mixtures were investigated under fertilized and unfertilized conditions. The mixtures were sown with legumes in crossing lines. Seeding rates were 8.0 g m −2 in sainfoin, 4.0 g m −2 in alfalfa, and 3.0 g m −2 in grasses. 2.2 g m −2 P in autumn, and 5.0 g m −2 N were applied in spring to one of each subplots. The contribution of the mixtures of alfalfa and sainfoin with grasses to the hay yield differed between years. Legume mixtures with one or two grass species gave higher dry matter yield than the single crop. Use of fertilizers increased the hay yield, which was statistically significant ( P<0.01) in all combinations. Under fertilized and unfertilized conditions the crop yield was higher in the presence of Onobrychis with one or two grass species than mixture of grasses with alfalfa. The superiority of the mixtures was also reflected in their large N harvests compared to pure stands of sainfoin or alfalfa and pure grasses. Furthermore the protein concentration of the hay from the mixtures was higher than that of B. inermis, A. elongatum, or Agropyron cristatum but lower than M. sativa. The hay from sole O. sativa plots had the highest crude protein concentration (172 mg g −1). The LER values of grass mixtures were higher in both single and binary grass mixtures in presence of Medicago (1.10, 1.22) and Onobrychis (1.08, 1.11, respectively) than those of their pure stands. In conclusion, for a sustainable production of high quality hay and greater N harvest with fertilizer, two grass species mixtures of sainfoin are recommended for long-purpose stands under similar conditions. Lower yields were harvested in the unfertilized plots and therefore fertilizer application is required probably because of insufficient P.