Influence of Microbial Inoculations on Cedrus deodara in Relation to Survival, Growth Promotion and Nutrient Uptake of Seedlings and General Soil Microflora

Abstract

Selected microorganisms (Laccaria laccata, Trichoderma viride, Bacillus subtilis, Pseudomonas corrugata and Azotobacter chroococcum) were used as inoculants to study their influence on seed germination, seedling survival and subsequent growth in Cedrus deodara. The microbial inoculations positively affected these parameters over control, in the following order: Azotobacter chroococcum Pseudomonas corrugata Bacillus subtilis Trichoderma viride Laccaria laccata.The major cause of seedling mortality was found to be (1) wilting of emerged seedlings by Fusarium oxysporum, and (2) cutworm attack. Bacterial inoculations were found to be superior in suppressing the proliferation of Fusariumsp., thereby enhancing seedling survival. One of the bacterial inoculants, B. subtilis, resulted in 76% seed germination, compared to 54% in control. Though inoculation with L. laccataresulted in maximum mycorrhizal infection (up to 72%) compared to48%in control seedlings, it afforded least protection against Fusariumsp., as well as minimal growth promotion. On the other hand, inoculation with T. viridesignificantly controlled wilting of seedlings and improved plant growth. Microbial inoculations were found to influence the soil microflora, nutrient status of the rhizosphere soil and that of different parts of seedlings. Enrichment of carbon was recorded in the rhizosphere soil. Enhanced nitrogen, phosphorus and potassium content of various plant parts indicated a positive influence also on nutrient uptake. The present study has implications for large scale forestry programs.