Soil quality in tropical hillslope soils can be assessed using spectroscopic methods to improve sustainable agricultural systems. By studying soil samples from Bolivia, the Philippines, and Indonesia, researchers found that the potassium permanganate test can effectively measure active organic carbon levels in soil. Fallowing agricultural fields can help restore soil fertility by increasing organic carbon content. Non-degraded soil generally has higher organic carbon levels compared to degraded soil. Agroforestry and nonagroforestry sites managed with different types of amendments showed variations in soil quality. Spectroscopic methods can be valuable for evaluating soil organic matter fractions and overall soil quality in diverse agricultural environments.