Soil morphological characteristics and profile variability across sugarcane landscapes

This research aimed to characterize soil morphological features and assess profile variability across sugarcane-dominated landscapes. This research will significantly advance our knowledge of the features and soil morphology of sugarcane in volcanic ash soils. The research was situated in Central Lampung, and topographic maps with a scale of 1:5,000 were used to describe the survey type. Approximately fifty-eight soil samples with twelve profile descriptions were collected from soil pits at three soil catenas (two under sugarcane and one under forest), and completely analyzed in the laboratory. The research resulted in the finding that the relationships between soil morphology and soil characters exist due to intensive leaching and erosion. All profiles were increasingly leached from the hilltop to the lower slopes. The lowest boundaries of the leaching process are impermeable hard iron layers between the tertiary and quaternary sediments (krokos layers) found in the BC or B3 horizons (depths of 70–120 cm). This phenomenon tends to form the open system in the sugarcane landscape; however, the forest system was closed. All soil characters are presented in depth functions to ease their analyses. Fertilization and dolomite application on the sugarcane soils increased only pH, P content, base saturation, and exchanged bases, decreasing exchanged Al and Al saturation in topsoils; these characteristics are relatively constant for all subsoils. Other soil properties were relatively constant. Soil compaction due to mechanization was a serious problem of soil degradation and fertility reduction, and became more serious due to decreasing infiltration rates from hilltop to lower slopes.