Effects of Fe and Zn fertilizer on biomass and photosynthetic characteristics of alfalfa

Trace elements are considered an important factor maintaining the production of alfalfa (Medicago sativa) pasture. A field experiment was carried out to determine the effects of Fe and Zn on the biomass and photosynthetic characteristics of alfalfa pasture. The results showed that application of Fe, Zn and mixture of Fe and Zn significantly increased the biomass of alfalfa pasture. Application of Fe or Zn didn't have significant effects on alfalfa height, but significantly increased the branches per plant, and the biomass of alfalfa pasture increased by 11.43%~12.89% and 6.31%~10.77% with Fe and Zn, respectively. Leaf stem ratio was the biggest when Zn was 15 kg·hm-2. Mixture of Fe and Zn didn't have significant effects on the height and branches per plant of alfalfa pasture, but improved the photosynthesis and increased the biomass of alfalfa pasture. The aboveground biomass and leaf stem ratio of alfalfa reached the maximum value when 9 kg·hm-2 Fe and 15 kg·hm-2 Zn was mixed, in which the biomass increased by 28.77% when compared with control.