Impact of fertilizers on total microbiological flora in planted and unplanted soils of long-term fertilization experiment

Abstract

Microbial population both in diversity as well as numbers in soil is influenced by the amount and type of various compounds entering soil through plant litter, root exudates and management factors like mineral and organic fertilizers under various climatic conditions. This in turn affects crop production and sustainability of soil health. Therefore, we tested total and number of various groups of microflora and also substrate use by Biolog to assess the metabolic capabilities of various groups of microbes from soils of long term fertilization experiment, Halle (Germany) having different mineral and organic fertilizer treatments in unplanted and planted soils with two crops viz., Secale cereale and Medicago sativa . High number of total microorganisms, nitrogen fixers and phosphate solubilizers were observed in the rhizosphere of Medicago sativa and Secale cereale compared to bulk soils. Microbial counts were specially higher in treatments of NPK+FYM (farmyard manure) and NPK in Secale. Medicago had more P solubilizers in yearly addition of phosphatic fertilizers compared to three yearly treatment. During substrate utilization test (Biolog) maximum utilization was found for sugars followed by amino acids in Secale whereas in Medicago sugars were followed by carboxylic acids.

Keywords:

• Long Term Fertilization Experiments
• Medicago Sativa, Secale Cereale
• Substate Utilization Test (Biolog)
• Microbiological Counts
• Phosphate Solubilizers