Microbial dynamics and soil carbon dynamics in okra as affected by irrigation methods
Land use changes and irrigation systems can impact the amount of C stored in the soil by altering C inputs and losses and also enriches soil microbial life. This project involves the study of microbial and biological properties, influenced by the irrigation methods in the long-term Vertisols located at ICRISAT, Patancheru, and Hyderabad. Enumeration of microorganisms (bacteria, fungi, actinomycetes) was done by dilution plating technique, using appropriate media; Microbial biomass carbon and nitrogen were determined using chloroform fumigation and incubation method. Vesicular arbuscular mycorrhizal colonization in roots of okra (Abelmoschus esculentus) plants was done by using root-staining method.
Bacteria, fungi and actinomycetes population was affected by the different irrigation systems. Soils under flood irrigation practices was showing higher biological and microbial values compared with soils under drip irrigation. The results showed that mean microbial population (43.7×103 cfu g-1 of soil) was higher in the drip irrigation on flat surface of farmer’s practices at both, the first picking and at second picking. Microbial biomass C was found to be higher (259.9 µg g-1of soil) in drip irrigation on BBF of improved practices at the first stage and on furrow irrigation on BBF surface of improved practices (201 µg g-1 of soil) during flowering stage. Biomass N and mineral N were found to be higher in improved systems compared to the traditional systems. Poor VAM colonization was observed under both the irrigation practices. Improved practices were showing 20-30% vam infection under drip irrigation practices and no colonization was observed under flood irrigation practices.