Enhancing phosphorus utilization efficiency and yield of Coleus forskohlii in low P soil using organic polymers coated DAP

The need for phosphate fertilizers has increased in line with the rising demand for agricultural goods. Of the various strategies to increase the phosphorus use efficiency (PUE) in crops, coating of water soluble P fertilizers with organic polymers is one of the options receiving importance at present. In this context, the laboratory and field experiments were conducted to synthesis organic polymers coated diammonium phosphate (DAP) using chitosan, sodium alginate and AMon the dry matter production, nutrient uptake and phosphorus utilization efficiency (PUE) in medicinal coleus under field condition. Results showed that the application of coated DAP with each 5 layers of chitosan and sodium alginate alternatively + AMF (Arbuscular mycorrhizal fungi) was effective in producing the highest biomass (7963 kg ha⁻¹), tuber yield (2156 kg ha⁻¹), nitrogen uptake (116.15 kg ha⁻¹), phosphorus uptake (20.62 kg ha⁻¹) and potassium uptake (127.87 kg ha⁻¹). The PUE and P recovery was also found to be high with the above treatment. This was comparable with DAP coated alternatively with four layers of each chitosan and sodium alginate with or without AM fungi and was found to improve the growth, nutrients uptake, PUE and P recovery when compared to uncoated DAP.