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.

18-31

Authors: Ognyan Kostov

It has been reviewed papers and personal investigations about soil tropical soils fertility. It was pointed out the importance of tropical soils for quantity and quality of yields of many crops. It was discussed soil quality, soil degradation, integrated nutrient management, maximization of the use the use of organic materials, balanced use of inorganic fertilizers, minimizing losses of plant nutrients, methods for conservation cropping management of low productive soils, polices for soil and fertility management and composting waste to improve and maintained tropical soils fertility.

42-52

Authors: Idris A.D., Olaniyan J.O., Affinnih K.O. and Ajala O.N

The study evaluated the forms and distributions of potassium in red laterite soils. Top soils samples 0 – 30cm, were randomly collected from thirty different major agricultural areas across Patigi LGA of Kwara State. Descriptive statistics was performed while regression analysis was used to assess the correlation between potassium forms. Results showed the exchangeable sodium (Na+ ) was very low to moderate. The values ranged from 0.00 – 0.27 cmol/kg soil. The exchangeable potassium (K+ ) of the soils is very low with values of 0.11 – 0.30 cmol/kg. Calcium (Ca2+) values ranged between 0.10 and 5.1cmol/kg soil while magnesium (Mg2+) ranged from 0.1 – 2.9 cmol/kg soil. The total potassium (K) obtained by concentrated perchloric acid (HClO4) had higher values (3.1 – 11.0 cmol/kg of soil) than other potassium types studied. The available potassium (K) was positively and significantly correlated with HCl Extractable K+ (r = 0.98); HNO3 Extractable K+ (r= 0.93) and HCl04 Extractable K+ (r=0.90) at P<0.01. The values of the extractable potassium increased in the order of NH4OAC

75-81

Authors: Nidal Shaban, Sergei Bistrichanov, Eman Kadum, Miroslav Tityanov

Sustainable development in education of horticulture imposes envolvement of new system in education of agricultural experts (in particular vegetable growers); include – etical view off point to the reality of production,synthesis of traditional practices (crop rotation, mixed crops, etc.), the love to the land inherited from ancestors and modern scientific achievements from this perspective which will have a positive environmental effect over the agrarian ecosystems and the environment in general. From this perspective lectures and practices should be based on the principles of integration of different systems and methods of production; this will include sustainable management of fertilizing and irrigation; energy use associated with production; integrated control of pests with sustainable application in the farms. These principles should be presented in a special section entitled “Sustainable Growing of Vegetables” which will form the basic knowledge related to the topic; they should be incorporated in a suitable place in the respective sections for individual crops where developed of details with active participation of trained people. In order to overcome the specified problems and ensure sustainable development of the sector its necessary to provide well-trained people who know not only the traditional technologies used at present but also the principles of sustainable agriculture as well, especially related with keeping natural resources to next generations.