Effect of Different Levels of Nitrogen Fertilization on Forage Yields and Quality of Hairy Vetch (Vicia villosa, Roth) Triticale (Xtritcosecale, Witmack) Mixtures

Intercropping legumes with cereals for forage production is a sustainable technique showing several environmental benefits.

This study aimed to investigate the effect of different levels of nitrogen fertilization on forage yields and quality of hairy vetch (Vicia villosa, roth) –triticale (X tritcosecale, witmack) mixtures.

The effect of five increasing nitrogen rates (0, 10, 20 30 and 50 kg N ha^-1) on the growth rate, forage yield, quality and interspecific competition of hairy vetch-winter triticale mixture was investigated under rainfed regime at the INRAT experimental station of Mornag.

Nitrogen application induced an increase in dry matter yield from 7.6 to 9 T DM ha^-1 obtained with 30 kg N ha^-1. This rate corresponds to the most efficient nitrogen rate as expressed by kg DM per Kg of added N. It reached a mean value of 47 kg DM kg^-1 N. Moreover, application of increasing nitrogen rate caused an increase in LER (Land Equivalent Ratio) of the mixture over the unit (LER=1.58 at 30 kg N ha^-1) and the competition ability of the triticale through CRt increase, suggesting the advantage of the mixture over sole crops. Crude protein content has been increased by two points from zero nitrogen application to other rates. However, no evident variation in fibers and Metabolizable Energy (ME) content was detected along with nitrogen application, but, mean values of 18% of CP content, 34% of NDF content and 9.7 Mj kg^-1 DM of ME were denoted as high forage nutritional values compared to other most Tunisian conventional forages.

The results of this study indicate that hairy vetch intercrops with winter triticale produced higher dry matter than the common vetch sole crop.