Evaluation of different levels of nitrogen and phosphorous on yield of Sainfoin under dryland conditions

Sainfoin (Onobrychis sativa) is a soft forage plant with high protein content. It has some characteristics such as: resistance to unfavorable environmental conditions as:low soil fertility, very low temperature, resistance to drought in dryland farming with acceptable yield, resistance to overgrazing in rangelands, and suitable for direct grazing. To study the effect of various levels of nitrogen and phosphorous on forage yield of Sainfoin a field experiment was conducted, using a randomized complete block design with four replications and two factors, nitrogen fertilizer with three levels (N0, N60 and N120 kg/ha) and phosphorous fertilizer with four levels (P0, P30, P60 and P90 kg/ha). The main purpose of this study was to introduce scientific strategies to safe and less harmful use of chemical fertilizers to produce acceptable yield with sustainable approach to environment conservation. In this research, dry matter yield (kg/ha), wet weight yield (kg/ha) and shoot height (cm) were measured. Except shoot height and dry matter of roots, other characteristics were significantly affected (P ≤ 1%) by various levels of nitrogen and phosphorous fertilizers. The interaction between these two types of fertilizers was not significant. Results of this study implies that N60P60 was the best fertilizer recommendation considering the economical aspects and acceptable forage yield.