Effects of Ammonia Water Fumigation on Root-knot Nematodes and Soil Microbial Diversity

This study evaluated the effectiveness of ammonia water fumigation in controlling root-knot nematodes (RKN), its influence on soil microbial diversity, and its impact on Nitrous oxide (N2O) emissions. The experimental treatments included control (CK), ammonia water (T1), ammonia water with the urease inhibitor N-(N-butyl)thiophosphoric triamide (NBPT) (T2), and ammonia water with the nitrification inhibitor dicyandiamide (DCD) (T3). The results indicated that T1 reduced the RKN population by 75.73%. Ammonia water increased N2O emissions and was mitigated by the inhibitors in T2 and T3. Soil enzyme activities, including those of urease, nitrate reductase, and nitrite reductase, were enhanced across treatments. The fungal Sobs index was significantly higher in CK than in the other treatments, whereas bacterial alpha diversity remained unaffected. Overall, ammonia water fumigation was effective for RKN control and modulated soil nitrogen cycling, while its associated N2O emissions highlighted the need for strategies to reduce environmental impact.