UDK 631.427.1(497.6) This paper studied the number of physiological and systematic groups of microorganisms in rekultisol under the different cultures at Stanari Coal Mine, and in variants of rekultisol where mineral fertilization and calcification were applied and in variants of rekultisol where only mineral fertilization was applied. The trial was set in the field conditions at the location of the internal part of overburden deposition site, near open pit Raskovac which is the part of Stanari coal mine. Mineral fertilizers were used as starter fertilizer and supplementary nutrition in the amount of 100-140 kg/ha of N and 40-60 kg/ha P2O5 and K2O and calcification was completed by adding 4 t/ha CaCO3. Microbiological analysis of the rekultisol determined the total number of bacteria, Azotobacter sp., ammonifiers, oligonitrophyls, actinomycetes and fungi. The aim of the research is to determine microbiological properties of rekultisol under small grains, potatoes, and grass-clover mixture at “Stanari” coal mine as well as to determine the effect of mineral fertilizers and calcification on the number of microorganisms in the rekultisol under different cultures. The total number of bacteria, oligonitrophyls, sporogenic ammonifiers, Azotobacter sp. and actinomycetes was higher in rekultisol under all of the tested cultures in the variant fertilizers + CaCO3 comparing to the variant without CaCO3, while the number of ammonifiers and fungi in rekultisol under all of the tested cultures was higher in the variant without CaCO3 in relation to the variant mineral fertilizers + CaCO3. In rekultisol under grass-clover mixture, higher total number of bacteria, oligonitrophyls and fungi was recorded in both tested variants, in relation to their number in rekultisol under potatoes and small grains. The number of actinomycetes was higher in rekultisol under potato in both variants, in relation to the number of actinomycetes in rekultisol under small grains and grass clover mixture. In rekultisol under small grains in variant mineral fertilizers + CaCO3 number of ammonifiers was the lowest (182 x 104g-1 absolutely dry soil), while the highest number of ammonifiers was recorded in rekultisol under grass-clover mixture in the variant without CaCO3 (1778 x 104g-1 absolutely dry soil). Azotobacter sp. count was lowest in rekultisol under grass clover variant without CaCO3 (68 x 102g-1 absolutely dry soil), while the highest Azotobacter sp. count was recorded in rekultisol under small grains in the variant with fertilizers + CaCO3 (123 x 102g-1 absolutely dry soil).

UDK 631.41(497.6) The research was conducted on deposol and rekultisol (technosols) in lignite mine Stanari. The main task of the formed grasslands is to improve the mechanical, chemical and biological properties of the rekultisol and deposol in the reclamation process. The fertility of Stanari deposol is extremely low in comparison to the natural soil. Grassland seeding through direct type of reclamation was conducted in 2008, 2011 and 2012 year. The conducted researches include the changes in the adsorption complex in the surface layer of the treated deposol in the reclamation process. Laboratory analysis of this technogenic soil were carried out before the reclamation and sowing started, and then in the process of reclamation at the end of 2012. On the experimental plots where reclamation measures were implemented, there is a slight improvement in most of the chemical characteristics of the rekultisol. Adsorption capacity and saturation degree of base cations in rekultisol were increased. Proper selection of the agromeliorative and other measures is required in the reclamation process. Well based seeding grasslands contribute to the creation of quality rekultisol.

UDK 631.4:632.954; 633.1:632.954(497.6) The aim of the study is to present the elements which must be considered while determining the risk of the mobility of the herbicides. Herbicides used for maize production have the special eco toxical significance and special risk because some are potentially mobile, they are used on the large surfaces during the rainy period and near rivers. Behaviour of the herbicides in the environment, particularly in the soil is very complex. It does not depend only on the characteristics of the herbicide, but on the many factors of the environment which are very variable. Regardless of this fact, there are experimentally determined physical-chemical indicators for each herbicide that show the possible behaviour of herbicides in the environment. Studied physical-chemical indicators of herbicide behavior are: Distribution Coefficient (Kd); Organic Carbon Partitioning Coefficient (Koc); Time of the Semi-Decomposition (DT50); Water Solubility (S); Groundwater Ubiquity Score (GUS); Henry's Law Constant (Kh), Vapor Pressure (PV) and the Dissociation Constant (pKa). Namely, herbicides, in larger or smaller measure, have “leaching potential“, which is ability to reach the underground water. One of the basic criteria for evaluating the herbicide ability to reach the underground water is related to indicators of mobility and persistency (DT50) herbicides, but neglecting some other criteria in that evaluation such as the amount of applying, characteristics of the soil and the aim of the crop growth. According to the EPA criteria, for the herbicides used in maize production in Bosnia and Herzegovina (BiH), the “trigger“ value will indirectly indicate if the herbicides have large leaching potential.

Surface mining, as a means of intensive exploitation of mineral raw materials and especially coal, is highly developed area of economy, therefore land degradation is intensive and leading to loss of the productive layer of soil. Biological reclamation of deposol should reduce the harmful consequences of exploitation. The number of systematic and physiological groups of microorganisms and their activities provide correlative infor­mation on the biological activity of the soil. In 2011, at the overburden disposal site in Stanari coal mine, the sowing of grass-clover mixture in previously treated deposol was carried out. The aim of the research is to the deposol biological activity in the process of biological reclamation based on the distribution of certain groups of microorganisms and dehydrogenase activity. General microbial activity in deposol in the process of reclamation is determined by the total number of bacteria, azotobacters, ammonifiers, oligonitrophyls, actinomycetes and fungi and the activity of the enzyme dehydrogenase.The research results indicated a greater abundance and deposol dehydrogenase activity in the process of biological reclamation compared to deposol (control).

The objective of this research work was to explore the scope, structure and quality of production and use of domestic wheat in the RS. The subject of the research was to determine the production of wheat in the Republic of Srpska, the needs for seed wheat, determine the amount imported, and to identify measures to increase domestic production of seed wheat and to reduce imports. The analysis of commercial wheat production in the period 2006-2010 showed that the production took place in the average area of ​​44,017.6 ha, with an average yield of 3.28 t/ha and total production of 145,591 t. The highest level of wheat production was recorded in 2007 when it was 172,481 t, and a minimum production was in 2010 when it was 84,647 t. In the Republic of Srpska in 2010, the area under wheat amounted to 33,641 ha, which required about 8,410 tonnes of wheat seed, and only 4.27% of the quantities of seed wheat needed for the RS market were produced in the RS, the rest came from imports. According to the Indirect Taxation Administration data, the Republic of Srpska imported 125 t of wheat seed in 2009. The quantities of imported wheat vary considerably from year to year and are influenced by the weather in the sowing season and the prices on the market. Analysis of seed wheat in period 2006-2010 showed that the seed wheat occupied an average area of ​​128.8 ha, with the average yield of 4.06 t/ha and the total average production of 514.2 tonnes. The highest production was recorded in 2008 when it was 656.25 tonnes, and the lowest in 2010, 359.4 tonnes. Demand for wheat seed of the Republic of Srpska, based on five-year average, amounts to 13,205 tonnes, in which the domestic production share is 514 tonnes or 3.9%. The value of domestic wheat seed production in this period was BAM 393,616, and the value of missing quantities of seeds that are imported is BAM 9,824,152, based on the domestic price.