Enzyme Activity and Rhizosphere Microflora under Sugarcane Monocropping as Influenced by Integrated Nutrient Management

Abstract

Sugarcane is one of the lead crops in North Coastal Andhra Pradesh. Farmers in North Coastal Zone are opting for raising more number of ratoons owing to its substantially low cost of production. Ratoon crops however seldom receive proper care and inputs due to considered it as a bonus crop by majority of farmers. Field experiments were conducted consecutively for six years in the same field (2012-13 to 2018-19) at RARS, Anakapalle to study the monocropping effect on soil biology under the influence of different nutrient management practices. Irrespective of the year of ratooning, plots which received 50% recommended dose of chemical fertilizers + 25% nitrogen though vermicompost + 25% nitrogen through green manure incorporation resulted in higher microbial population over chemical fertilizers alone. Activity of dehydrogenase and active carbon pool also showed similar trend in multi-ratooning system of sugarcane. Rhizosphere microbial population at different growth stages revealed that, azospirillum population was observed highest followed by azotobacter while lowest population counts of phosphorus solubilizing bacteria were observed. Highest population counts were recorded in INM plots and population was highest at formative later reduced to harvest. INM with 50% RDFN + 50% through organics (66.80 t ha-1) recorded at par yields with 100% RDF (67.28 t ha-1).