Evaluating Land Sustainability Indicators Through Structural Stability Changes In Deforested Land

Abstract

Structural stability of soils is an important indicator for land sustainability because it controls the depth of topsoil and soil quality, particularly in deforested areas. The objective of this research was to evaluate the dynamics of soil structure across five common indigenous ecosystems (banana-, rubber-, and coffee-agroforests, Imperata cylindrica grassland, and secondary forest). Wet and dry sieving techniques were performed to assess aggregate size distribution and aggregate stability. The highest amount of water stable aggregates was observed in the I. cylindrica grassland and secondary forest at 55% and 53%, respectively. The greatest dry aggregate stability was found in rubber agroforest (78%), banana agroforest (77%) and secondary forest (74%). Both mean weight diameters and geometric mean diameters of aggregate in the soil profile of 30 cm were highest in agroforests compared to other ecosystems. Aggregate size distributions and their stability were positively correlated with soil organic C. The data showed a positive significant correlation between the mean weight diameter, geometric diameter, and soil organic carbon content. This study indicates that structural stability provides better indicator for soil quality improvement or degradation compared to soil organic C measurement. The dynamics of soil structure were relatively sensitive to cultivation practices. Therefore, soil aggregation is recommended to be used as soil quality indicator before the change of soil organic C can be detected.