Effects of mixed cropping Vicia sativa and nitrogen fertilizer on nitrogen yield of Avena sativa pastures in Zhaosu, Xinjiang

• LI Songsong, 
• YU Hui, 
• WANG Ningxin, 
• XIA Shumiao, 
• ZHU Yaqiong, 
• CHEN Xue, 
• ZHENG Wei