Studies on soil-landscape relationships are necessary to improve our understanding of the spatial distribution and variation of soils for their sustainable management. This study evaluated the relationship between soil properties and landscape position in the northern volcanic mountain of Leyte, Philippines. Five soil profiles located on summit, shoulder, backslope and footslope positions were evaluated. Findings revealed that the degree of soil development as well as the soil morphophysical and chemical properties varied with landscape position. The soil in the most stable position (summit) had thicker solum and slightly more developed soil profile than the soils in other landscape positions. On the other hand, soils in the unstable position (backslope) generally had thinner solum. All the five soils also revealed the influence of the andesitic volcanic parent material on their properties. They all showed some properties typical of Andisols such as low bulk density and high pH in NaF although they were classified as Andic Dystrudept. The soils all possessed physical and chemical constraints for crop production.

There is an urgent need for soil erosion data from marginal uplands in the country. This study evaluated the occurrences of soil erosion in the marginal uplands of lnopacan, Leyte. Field soil erosion indicators were assessed in different portions of the study site and erosion plots were established in the corn and sweetpotato fertilizer experiments to measure erosion rates. Field indicators of soil erosion such as rills, cracks across slopes, exposed rocks, thin surface soil and eroded sediments in waterways were common in various parts of the marginal upland studied. Soil erosion rates measured on erosion plots were higher from the corn field than from the sweetpotato field. Application of chicken manure and vermicast resulted in lower soil erosion rates due to improved soil structure. Plots without crop cover gave the highest erosion rates. The degree of soil erosion in the marginal upland can be considered as moderate to severe.

Limitations of existing definitions of similar and contrasting soils for soil survey interpretations relating to both inclusions in map units and landscape patterns of soils led to the development of a new procedure for characterizing soil contrast. Six classes, or levels of soil contrast, are defined based on differences in intrinsic soil properties. Soil texture, coarse fragments, depth of rooting, drainage, permeability, pH, salinity, slope, erosion, and flooding are used to define 12 parameters for comparing soils. The range of values for each parameter is divided into a small number of discrete classes to facilitate comparisons. Within a given parameter (e.g., surface texture), class comparisons are rated as very similar, similar, somewhat contrasting, contrasting, or very contrasting, depending on whether the property values are in the same class, an adjacent class, nearby classes, or remote classes. Repeating this procedure for each parameter generates a set of 12 parameter contrasts for the two soils being compared. The distribution of contrasts among contrast levels determines the overall degree of contrast between the two soils. Where one or two parameters have a higher contrast than any of the others, that contrast level becomes the overall degree of soil contrast. Where several parameters vary at the same level, the cumulative effect of multiple variation is expressed by increasing the overall contrast to the next higher level. Advantages of the new model include multiple classes, definition of contrasts in terms of soil properties, and a precise procedure that can be duplicated by any two people given the same set of data.