Effects of different nitrogen and phosphorous fertilizer on yields and nutrients of Vicia unijuga

The experiment was performed to investigate the influences of nitrogen (0, 50, 75, 100 kgha-1) and phosphorous (0, 70, 140, 210 kgha-1) fertilizer on nutrients and yields of Vicia unijuga. It was found that both 75 kgha-1 nitrogen fertilizer and 140 kgha-1 phosphorous fertilizer could maximize the dry matter yields of V.unijuga, the highest yield was 3 048 and 2 752 kgha-1, respectively. The yields were 50% and 35% higher than those with no fertilizer, respectively. In addition, by using 75 kgha-1 nitrogen fertilizer and 140 kgha-1 phosphorous fertilizer, the contents of Cu, Mn and Zn elements were much higher than those without fertilizer (P0.05). Under the 50 kgha-1 nitrogen fertilizer and 70 kgha-1 phosphorous fertilizer, the contents of water soluble sugar and crude protein were all the highest. The contents of water soluble sugar and crude protein in 50 nitrogen were 11.0% and 23.5% higher than those without nitrogen. It should be noted that excessive amounts of nitrogen or phosphorous fertilizer would decrease the yield and quality of V.unijuga, and the actual amount of fertilizer should be considered in practice.