FRACTIONATION OF WATER-STABILIZED AGGREGATE AND C AND N CONTENT OF SOIL DUE TO THE CONVERSION OF AGRICULTURAL LAND IN SUBAK SEMBUNG, DENPASAR

The study entitled “Water-Stable Aggregate Fractionation and Soil C and N Contents Due to Agricultural Land Conversion in Subak Sembung, Denpasar” aims to analyze the impact of paddy field conversion into residential areas on soil structure and the content of carbon (C) and nitrogen (N) in Subak Sembung, Denpasar. Driven by urbanization and tourism development, Bali has experienced extensive land-use changes that threaten soil fertility and carbon storage capacity.

The research employed the water-stable aggregate fractionation method to separate soil into different aggregate size classes (>1000 µm, 250–1000 µm, 53–250 µm, and <53 µm), allowing detailed observation of soil aggregate stability and its relationship with carbon and nitrogen distribution. Soil organic carbon was analyzed using the Walkley-Black method, while total nitrogen was measured by the Kjeldahl method.

Results indicate that land-use conversion significantly decreases soil aggregate stability, as shown by the higher proportion of microaggregates (<53 µm) and reduced macroaggregates (>1000 µm) in residential soils compared to active paddy fields. This degradation of soil structure suggests a decline in the soil’s ability to store carbon and nitrogen, potentially accelerating soil degradation and greenhouse gas emissions.

This study provides critical insights for sustainable land management policies in Bali, highlighting the need to preserve traditional Subak systems that maintain soil health, water regulation, and agricultural sustainability.