Bulgarian Journal of Soil Science

99-105

Authors: Ivaylo Kirilov, Metodi Teoharov

The present article considers the criteria for diagnostics and identification of sandy soils in Bulgaria. The research so far has proved that they have a soil profile structure of the type A-AC-C, sand content over 75% in the surface horizon and of 80-90% in the soil formation rock. With some exceptions they are non-fragmented soils. The humus content most often varies from very low to low and average by way of exception. The total content of iron is most often low and in isolated cases it is higher, which could be considered as an exception, too. The soil reaction is slightly acidic to slightly alkaline. The relative and volumetric density are high and very high and the general porosity vary from low to average. According to the water-physical indicators these soils are hydrophilic and very rarely - hydrophobic. The carbonate variation determines to a greatest extent the Sandy soil classification on a lower taxonomic level. The sorption capacity is low to average while the base saturation is high. The content of primary minerals is inherited and is determined by quartz and feldspars. This defines sandy soils as primitive ones with underdeveloped soilformation process.

112-122

Authors: Chioma Mildred Ahukaemere, Donald Nweze Osujieke, Bernardine Ngozi Ndukwu

Horizon differences in soils influence ability of crops to obtain nutrients and indeed support other uses. The study aimed at investigating the micronutrient (Cu, Mn, Fe, Zn) contents of horizons of two different pedons which lies on similar parent material (Coastal plain sand) in Imo State. Random survey technique guided by the geologic map of the area was used in siting one profile pits on each of the locations. The profile pits were described; and identification and delineation of horizon boundaries were accomplished using FAO guidelines before actual sample collection for laboratory analyses. Soil data were subjected to coefficient of variation (CV) analysis. The results of the micronutrients indicated range values of 0.02- 0.36 mg kg-1 for Mn, 36.6-108 mg kg-1 for Fe, 0.091-0.256 mg kg-1 for Cu and 0.205-0.774 mg kg-1 for Zn in pedon 1. In pedon 2, the ranges were 0.13-1.09 mg kg-1 for Mn, 19-50.6 mg kg-1for Fe, 0.143-0.613 mg kg-1 for Cu and 0.22- 0.962 mg kg-1 for Zn respectively. The values of Zn, Cu and Mn were below the critical limits recommended for arable crop production. However, Fe concentration was generally high in all the horizons and was above the critical level recommended. Hence, the soils were surplus in iron but deficient in Cu, Mn and Zn. It is therefore recommended that agronomic requirements should consider these essential edaphic attributes in the study area.

133 - 147

Authors: Vladimir Ilinkin, Peter Zhelev, Dimitar Dimitrov

The paper presents results of an investigation on Fluvisols. The soils are located in “Gladino” gravel quarry, Chepintsy district, Bulgaria, on an area of 1.043 km2. Soil samples were taken from fifteen soil profiles at a depth of 0-100 cm. The factors of soil formation were characterized and it`s physicochemical properties were studied. The changes in physicochemical properties were investigated at different soil depths and the relationships between different soil characteristics were tested by correlation analysis. The results reveal that some soil characteristics, such as the content of clay, sand, organic matter, and the soil porosity have strong positive or negative correlation with the soil depth. The soil characteristics such as acidity or alkalinity of soil (pH), the content of loam, bulk density, Total Kjeldal Nitrogen (TKN), mobile phosphorus and potassium demonstrated an insignificant or weak relationship with the soil depth. There are significant correlations between the physicochemical soil properties in 28 out of 78 cases. All results are discussed in relation to soil formation processes in the studied region.