Bulgarian Journal of Soil Science

101 - 109

Authors: Ludmila Malinova; Kameliya Petrova

Results are presented for the chemical composition of the forest litterfall and lysimetric waters of Cambisols from the intensive monitoring stationary sample plot of the forest ecosystems. Litterfall (litter biomass fraction) had fallen on the soil surface with acid reaction, which in the period 2011 - 2018 varied from 5.1 to 5.4. The established contents of calcium (6.9 mg.g-1 ), magnesium (0.52 mg.g-1 ), potassium (3.58 mg.g-1 ), nitrogen (7.28 mg.g1 ) and phosphorus (0.55 mg.g-1 ) were low and those of manganese (1754 µg.g-1 ), iron (185 µg.g-1 ), copper (11 µg.g-1 ) and zinc (36 µg.g-1 ) were high. The lysimetric waters in the surface horizon were very strongly acidic – pHH2O= 4.6. The amounts of all the tested parameters in them were very low – dissolved organic matter (8.0 mg.dm3 ), potassium (2.6 mg.dm3 ), calcium (5.7 mg.dm3 ) and others. Only the content of manganese was increased, which in some years exceeded the maximum value pointed in the literature for the European forests. It is assumed that degradation processes take place in the mineral part of the soil which lead to its impoverishment of macro and microelements.

117 - 125

Authors: Theophilus Olufemi Isimikalu; John Olajide Olaniyan; Bashiru Ademola Raji

Agriculture has very important social and economic footprint in Africa. Its soil resource is however threatened by degradation resulting from mismanagement, due to lack of knowledge on important soil functional properties such as mineralogy, which impact many soil processes. This study was therefore conducted to access variations in soil oxide mineralogy in soils formed from differing bedrock lithologies. Soil sampling was carried out on soils from three different bedrock types; basement complex rocks, recent alluvium, and Nupe sandstone in Kwara state, southern Guinea Savannah of Nigeria. Data was subjected to analysis of variance to determine significant differences in treatment means (p<0.05), and correlation analysis was performed to determine relationships between measured variables. Elemental oxide composition of soils from the different bedrock materials were found to be significantly different. Soils from all three bedrock types had very high amounts of silica by mass (>80 %). The highest mean percentage of 90.59 was recorded in recent alluvium-derived samples, while the least value of 80.75 % was recorded in basement complex-derived samples. Aluminum and iron oxides were the most saturating metal oxides in all the bedrock types, and significantly higher values of 5.65 % and 2.71 % for Al2O3 and Fe2O3 respectively were recorded in basement complex-derived soils. Dissimilar trends of mineral oxide relationships were observed in soils from the different lithologies, which are likely a result of bedrock characteristic, environmental and hydrologic factors. The relationships established between oxide minerals in this study could serve as a foundation for subsequent investigations into mineral interactions in the soils.

142 - 151

Authors: Sunusi Abdu Yusif; Mansur Abdul Mohammed; Nurudeen Olalekan Popoola; Hammed Yekeen; Abba Nabayi; Hamid Yakubu

This research was conducted at the screenhouse of Biological Science, Usmanu Danfodiyo University, Sokoto, Nigeria, to determine the ameliorative effect of biochar application on selected chemical properties of acidic soil. The acidic soil used for the experiment was collected from Centre for Agricultural and Pastoral Research (CAPAR), Dabagi, Usmanu Danfodiyo University, Sokoto while the biochar used was obtained from Labana Rice Mill, Brinin-Kebbi, Kebbi State. The biochar was applied at rate of 0, 10, 20, 30, 40, 50, 60 and 70 t/ha. The experiment was laid out in a completely randomized design (CRD) and replicated three times. Data were collected on some soil chemical properties and were subjected to Analysis of Variance (ANOVA) and significant means were separated using Duncan’s Multiple Range Test at 5% level of significance. The results showed that successive increment in biochar rates virtually increased all the soil chemical properties tested for, with 70 t/ha of biochar rate significantly (p≤0.05) higher than the other biochar rates. A field trial of long term experiment with lower doses of biochar rates supplemented with inorganic fertilizer should be conducted in order to have more feasible doses of biochar in the remediation of acidic soil.