Red soils under mediterranean type of climate: Their properties use and productivity

Abstract

Red soils constitute a moderate portion of the total agricultural land, supporting several land utilization types. in the Bursa province northern Turkey. Five red soils were selected in this region to ascertain their properties and productivity. Their moisture regime is xeric. These soils were developed on limestone and belong to the great group of Rhodoxeralfs. They occur on well-drained sites, mainly on shoulder and backslope geomorphic surfaces; they have been affected by erosion and, in some cases, the argillic horizons have been exposed at the surface. The depth distribution of iron and manganese oxides indicates that these red soils are probably at a moderate development stage. The pedogenetic environment, that favors the formation and stability of hematite. leads to the assumption that in the studied red soils hematite is the predominant iron oxide responsible for soils red coloration. Field observations and laboratory analyses suggested that red soils in the region are of low to medium productivity, preservation of organic matter and the use of nonacidifying fertilizers should be practiced to improve their productivity.