Bulgarian Journal of Soil Science

4 - 12

Authors: Tsetska Simeonova, Maya Benkova, Lyuba Nenova, Irena Atanassova

The cationic and anionic composition, i.e. K +, Na+ , Ca2+, Mg2+, Cl- , NO3 -, phosphates,SO4 2- and dissolved organic carbon (DOC) in soil solutions of Technogenic soils (Technosols)from the area of Maritsa-Iztok coal mine basin in Bulgaria was analyzed and links with overburden strata were discussed. Two sites are located at the Mednikarovo village with humus and non- humus reclamation under grass vegetation. The other two are situated near the village of Obruchishte (non-vegetated and pine-vegetated). The sites differ in their textural composition, physico-chemical and hydro-physical properties. It was found that major cations and anions in the soil solutions at Mednikarovo site did not exceed the maximum permissible concentration limits (MPCL) for drinking water, while in solutions from the Obruchishte Technosols, composed of black clays intermixed with coal ash maximum permissible concentrations of sulphate (250 mg.l -1), phosphate (0.5 mg.l-1 ), calcium (150 mg.l-1 ) and magnesium (80 mg.l-1 ) were exceeded and may pose a threat to contamination of surface and sub-surface water of reclaimed soils.

27 - 33

Authors: Alexander N. Sadovski

The paper traces the emergence and development of the problem of scheduling irrigation as a scientific and practical issue at the Institute of Soil Science "N. Poushkarov" for half a century. The main participants in this process and the leading scientific publications are noted.

48 - 62

Authors: C.M. Ahukaemere, N.S. Obasi

Land capability classification (LCC), fertility capability classification (FCC) and land suitability evaluation of some soils of Ebonyi State were carried out for cassava, yam and maize cultivation. Land capability and fertility capability classes were obtained using the method of United State Development of Agriculture (USDA) while suitability evaluation was done using the Food and Agricultural Organization of the United Nations’ (FAO) conventional method. Four (4) pedons were investigated, two from Akaeze (Asu river group)and two from Abakaliki (Asata nkporo shale) . Results of LCC showed that sites 1 and 2 (Asu river group) were classified as class II soils while sites 3 and 4 (Asata nkporo shale) were classified as class IV soils. According to FCC results, the major classes obtained were SM,g,k for site 1, A,g,k for site 2 and SA,e,k,r for sites 3 and 4 respectively. The results of land suitability evaluation showed that despite climatic factors and topography, there was no highly suitable (S1) land for maize, yam and cassava cultivation. Total nitrogen and organic carbon contents of pedons 1, 2 and 4 were marginally (S3) suitable for the production of yam and cassava while the nitrogen and organic carbon contents of pedon 3 were currently not suitable (N1) for yam and cassava cultivation. Soil texture, pH, ECEC and available phosphorus made the 4 sites moderately suitable (S2) for cassava and yam cultivation. Also, the acidic condition of the soils made all the sites moderately suitable for maize production. From the results of the aggregate suitability ratings, the major constraint for yam, cassava and maize cultivation in the sites was soil fertility (f) resulting from low organic carbon and total nitrogen contents of the soils. Though not optimum for the cultivation of the crops evaluated, the soils can still produce increased and sustainable crop yield if the appropriate husbandry practices are adopted, with particular reference to organic and nitrogen fertilizer application.