Soil Fertility Responses to Different Nitrogen Application Approaches Involving Prilled Urea and Foliar Nano-urea in Wheat

Abstract

Wheat productivity depends strongly on adequate nitrogen nutrition; however, conventional prilled urea is often associated with low nitrogen-use efficiency and substantial nutrient losses. Foliar nano-urea has emerged as a potential complementary nitrogen source that may improve nitrogen-use efficiency while reducing dependence on conventional urea. Nevertheless, information on its effects, when combined with different levels and timings of prilled urea, on post-harvest soil fertility and nutrient availability at different soil depths remains limited. A field experiment was conducted between December 2024 and April 2025 at JNKVV, Jabalpur, to investigate the effects of different nitrogen application approaches involving prilled urea and foliar nano-urea on soil fertility under wheat (Triticum aestivum L.). The randomized block design comprised nine treatments ranging from an unfertilized control and 0 N + 100% PK to combinations of reduced recommended nitrogen dose (RDN) with nano-urea sprays, alongside 100% recommended dose of fertilizer (RDF). Except in T1, 100% P2O5 and K2O were applied uniformly to all plots as basal applications. Post-harvest soil samples collected from 0–15 and 15–30 cm depths were analysed for soil organic carbon, available nitrogen, phosphorus, potassium, sulphur, and DTPA-extractable zinc. The results revealed that soil pH, electrical conductivity, organic carbon, and available zinc were not significantly affected by the different combinations of prilled urea and nano-urea. Soil available nitrogen and phosphorus were significantly influenced by these combinations, with the highest available nitrogen and phosphorus under the 100% recommended dose of fertilizer (T9), which remained statistically at par with T5 and T8. The maximum available potassium and sulphur were observed under the treatment receiving 0 N + 100% PK (T2), whereas integrated application of prilled urea and nano-urea resulted in significantly lower available potassium and sulphur owing to greater nutrient uptake by the crop. Irrespective of treatment, nutrient availability was generally higher at 0–15 cm than at 15–30 cm depth. The results suggest that appropriate integration of prilled urea with foliar nano-urea maintained soil fertility comparable to the recommended fertilizer schedule, indicating that nano-urea can be effectively integrated with prilled nitrogen fertilization for sustainable wheat production.