Comparative Efficacy of Coated Diammonium Phosphate Formulations for Improving Crop Productivity and Nutrient Uptake in Maize

Fertilizer use efficiency is the major problem behind low crop productivity on calcareous sandy loam soils, mostly for exhaustive crops like maize. Improving maize productivity to meet food requirements is among the priority research areas for scientists. The study explores the efficacy of coated diammonium phosphate (DAP) with phosphate solubilizing bacteria (PSB) and their extracted metabolites to improve maize growth and soil health. For this purpose, the efficacy of conventional DAP is compared with that of coated DAP (C-DAP) to improve soil nutrient dynamics, maize seedling growth, the antioxidant system, and nutrient uptake in grains. Results showed that C-DAP significantly improved maize growth as compared to uncoated DAP. Bacterial and metabolites coated DAP formulations exhibit increased soil available phosphorus by 44% and 41% and extractable potassium by 41% and 43%, respectively, at 100% of the required P dose. Coated DAP treatments also enhanced microbial biomass carbon in rhizospheric soil, indicating a positive influence on soil microbial communities. Furthermore, bacterial and metabolites coated DAP formulations enhanced relative water contents (44% and 40%), membrane stability index (45% and 47%), and chlorophyll contents (37% and 39%), respectively. The present findings conclude that the use of microbial and metabolites coated DAP is an effective strategy to improve maize growth, physiology, and nutrient use efficiency in a sustainable manner to address food security.