Dynamics in microbial immobilization and transformations of phosphorus following organic amendments in saline soils of Southern Bangladesh

The significance of phosphorus (P) in plant physiology is impeded by its limited availability in saline soil, necessitating a comprehensive understanding of P transformation for effective P management. An incubation experiment was conducted in saline soil with different organic amendments (OA), glucose (T1: 2 g C kg -1 ), rice straw biochar (RSB) (T2 and T3: 2 and 4 g C kg -1 , respectively), and cow dung (CD) (T4: 2 g C kg -1 ), alongside a control (T0). Results: The study found that RSB and CD led to improvements in soil properties such as exchangeable and water-soluble Na and K, cation exchange capacity (CEC), total N (TN%), and chloride (Cl - ) content. Over 90 days, T3 showed consistently stable microbial biomass carbon (MBC), maintaining 2.4-3 times higher levels than the control (p<0.05), and contributing the maximum microbial biomass P (MBP). The post-incubation C/P ratio in T2 and T3 ranged from 8.3:1 to 8.4:1, indicating a shorter time for RSB for microbial biomass contributing to MBP. After  incubation, available P (AP) was 1.84 times higher in T3 (p<0.05), whereas T1, T2, and T4 exhibited similar AP. PCA analysis revealed that among the variables, P associated parameters (i.e., AP, MBC, and MBP) were most significantly enhanced by RSB-T3 treatment.

• Research Project