Improvement of Quality and Quantity of Alfalfa Forage Yield by Using Chemical and Bio-Fertilizers

This research was conducted to study the effects of chemical and bio fertilizers on forage yield of alfalfa in a factorial experiment by using a randomized complete block design with 3 replications in 2012-2013 in Arak, Iran. Treatments were chemical fertilizers in four levels (control, potassium, phosphorus and whole micronutrients) and biological fertilizers in four levels (control, soil potassium solublizing bacteria, nitrogen-fixing bacteria and soil phosphorus solublizing bacteria). The results showed that the highest yield of alfalfa, in the first cut, was 1.76 t/ha by the use of phosphorus solublizing bacteria and 1.57 t/ha by using soil potassium solublizing bacteria. Although in the second cut the differences between chemical fertilizer and their interaction with biological fertilizer was not significant, but application of biological fertilizers could affect alfalfa yield in the second cut significantly. Application of soil potassium solublizing bacteria increased forage yield of alfalfa from 1.74 to 2.48 t/ha. The results also revealed that dry forage yield of alfalfa in control treatment was 2.5 t/ha and it was increased to 3.7 t/ha by using phosphorus solubilizing bacteria which is 1.2 t/ha higher than control.