Vol. 7, Issue 6, Part A (2025)

Optimizing fertilizer application is critical for maintaining soil health, promoting crop productivity, and minimizing environmental degradation. The advent of nano-fertilizers offers new opportunities for efficient nutrient management. This study evaluated the effects of conventional urea and nano-urea on soil biological properties and enzyme activities in tomato cultivation. Significant differences were observed in soil pH among treatments, with the highest (7.51) pH recorded in T₁₂ (50% RDN as basal dose + nano-urea (2 ml L^-1) at 30 and 45 DAT). However, organic carbon content and soil microbial biomass remained unaffected. Notably, nitrogenous fertilizer application significantly influenced soil enzyme activities, with T₄ (100% RDN with nano-urea at 30 and 45 DAT) exhibiting the highest (20.42 μg TPF g^-1 soil 24hr^-1) dehydrogenase activity, and T₁ where, 100% RDN was applied only through the conventional urea showed the highest (5.96 and μg PNP g^-1 h^-1) acid phosphatase activity. These findings provide insights into optimizing fertilizer management for improved soil health and enzyme activity.