Effect of Nitrogen and phosphorus fertilization on forage quality of Eruca sativa in winter rangelands (Maravehtapeh, Golestan provinc)

Determination of forage quality is one of the fundamental factors for sound management of rangelands. Nitrogen and phosphorus fertilization of rangelands causes increasing forage quality.In this study, forage quality of Eruca sativa in three years (2004, 2005 and 2006) weremeasured in flat and northern sloppy rangelands in Maravehtapeh. In this study, 0, 50 and 100 kg N/ha and 0 and 25 kg P/ha fertilizer rates were applied. Forage quality index such as crude energy, crude protein, crude fiber, crude nitrogen and ADF (Acid Detergent Fiber) were measured in this study. Results showed that, nitrogen fertilizer increased the crude nitrogen, crude protein and crude energy and decreased the crude fiber and ADF. Phosphorus fertilization had few effects on forage quality. Nitrogen fertilization with 100 kg/ha increased forage quality.Forage quality rates increased in 2006 owing to optimum weather condition in this year. Forage quality rate is same in each flat and northern sloppy rangeland was the same. Interaction effects between two fertilizers in northern sloppy rangeland was significant.