Journal of Agronomy and Field Innovations

Background: Soil biological properties respond rapidly to management and provide early indication of changes in soil fertility long before physicochemical parameters shift measurably.
Objective: This study evaluated soil enzyme activities and microbial biomass carbon (MBC) as indicators of soil health under contrasting nutrient management systems and examined their relationship with crop productivity.
Methods: A field experiment was conducted in a randomized complete block design with six treatments—control, chemical fertilizer, farmyard manure, compost, biofertilizer, and integrated nutrient management (INM)—replicated thrice. Soil samples (0–15 cm) were analyzed for physicochemical properties, MBC (chloroform fumigation-extraction), and dehydrogenase, urease, β-glucosidase, acid phosphatase, alkaline phosphatase, and catalase activities. Crop growth, yield, and nutrient uptake were recorded, and data were subjected to ANOVA, correlation, and principal component analysis.
Results: INM and compost treatments recorded the highest MBC and enzyme activities, significantly (P < 0.05) exceeding the control and chemical fertilizer treatments. MBC correlated positively with organic carbon (r = 0.86) and grain yield (r = 0.79). Dehydrogenase and β-glucosidase showed the strongest associations with nutrient uptake and yield.
Conclusion: Integrated and organic-based nutrient management enhanced soil biological activity and crop productivity simultaneously, confirming MBC and enzyme assays as sensitive, cost-effective indicators for monitoring soil health in sustainable cropping systems.