Ammonium Polyphosphates as Potent Source of Phosphorus for Crops

摘要

Ammonium polyphosphates which are pnmanly pyrophosphates, are completely water soluble fertilisers and new additions to the list of phosphatic fertilisers in Indian agriculture that are available through commercial channels mid we presently under widescale field trials. Ammonium polyphosphates (APP) hU produced in 1960 gained wide importance in many parts of the world. The granular or solid ammonium polyphosphates which are high analysis binutriert term contain 25-55% of their P as tri- or tetra-ammonium pyrophosphates and reninu~ as mono- or diammonium orthophosphate. The solution or fluid anvnarmmu polyphosphate fertilisers consist of clear solution and base suspensions. hum ammonium polyphosphates are of special interests as potential phosjulc fertilisers in view of their high P and N content, marked degrees of water sokdWy of phosphates, higher residual value and sequestering action with some of the essential micronutrients such as Zn, Fe and Cu and lower cost of their production and transportation. The available information on the efficiency of ammonium polyphosphates compared to orthophosphate fertilisers for crops, hydrolysis of ammonium polyphosphates (pyrophosphates to ortho-phosphate), residual effect and micronutrient chelation in soils are critically discussed.