Broad-spectrum pH functional chitosan–phosphatase beads for the generation of plant-available phosphorus: utilizing the insoluble P pool oleh Kasturika Konwar, Himanku Boruah, Rimjim Gogoi, Anudhriti Boruah, Arup Borgohain, Madhusmita Baruah, Subham Protim Gogoi, Tanmoy Karak, Jiban Saikia