Agricultural Intensification Reduces Collembola and Acarina Abundance in Traditional Balinese Subak Rice Farming Systems

Agricultural intensification through the use of synthetic fertilizers and chemical pesticides has altered soil biological health, yet conventional soil fertility assessments typically focus only on chemical parameters. This study aimed to evaluate the effect of agricultural intensification on the abundance and diversity of mesofauna (Collembola and Acarina), analyze the relationship patterns between soil fertility parameters and mesofauna abundance, and compare the consistency of decline patterns using two sampling methods in Subak Abasan, Badung Regency, Bali. Mesofauna sampling was conducted using Berlese-Tullgren funnel and pitfall trap methods with nine replicates per system, while soil analysis included five chemical parameters. Data were analyzed using Kruskal-Wallis test with post-hoc Mann-Whitney U. Results showed that although all three systems had "High" chemical fertility status based on Bogor Soil Research Center criteria (1995), Collembola abundance decreased by 79.2-83.9% and Acarina decreased by 90.9-100% from organic to conventional systems. Families Sminthuridae and Entomobryidae were completely lost from semi-organic and conventional systems, while predatory mites Mesostigmata were lost from conventional systems. Total-P and Total-K parameters showed inverse patterns with mesofauna abundance. Conversely, mesofauna increased along with increasing Organic-C, CEC, and Base Saturation. These findings indicate that mesofauna abundance responds to the agricultural intensification gradient differently than chemical fertility parameters, making it a complementary indicator for assessing the impact of intensification on soil biodiversity and biological functions.