Effect of foliar application of Azotobacter, Azospirillum and Beijerinckiaon leaf yield and quality of mulberry (Morus alba)

A field experiment was conducted for two years (1994-96) to evaluate three nitrogen fixing bacteria (NFBs) namely Azotobacter, Azospirillum and Beijer inckia as foliar biofertilizers on mulberry (Morus spp.). Foliar applicatio n of these bacteria in their specific culture media with half of the recomm ended dose of N as a basal application of chemical fertilizer were compared with the recommended dose of N (300 kg/ha per year in four equal splits) b ut without biofertilizer. Other controls for comparison were respective cul ture media with half N. All the NFBs improved leaf yield over their respect ive controls (specific culture media). The addition of Azotobacter resulted in significantly greater yield than that given by the recommended dose of N. The Beijerinckia treatment resulted in a leaf yield equal to that from t he recommended dose of N and Azospirillum reduced leaf yield in comparison to that from the recommended N treatment although the yield from Azospirill um treatment was more than that from the culture medium treatments. A combi nation of NFBs where Azotobacter was one of the components improved leaf yi eld over single NFB treatments. NFBs also resulted in improved leaf quality as indicated by their protein content and their impact on silkworm rearing and cocoon production when treated leaves were subjected to bioassay. The use of these NFBs, particularly the Azotobacter, as a foliar biofertilizer to increase mulberry leaf production has not been investigated before.