In order to compare greenhouse gases emission from different animal manures and to explore how different animal manures effect on soil mineralization, three kinds of materials, cattle, goat and chicken manure were amended to soil for 14 days incubation as CtS (cattle manure-amended soil), GS (goat manure-amended soil) and ChS (chicken manure-amended soil). Cumulative NH3 emissions in all treatments were rapidly increased until day 7 and then it was slightly increased in three manure-amended soils but maintained in control until day 14. GS had the highest NH3 emission at 0.14 mg kg-1 during the entire experimental period. Emissions of CO2 were highly increased by 7.8-, 9.0- and 12.4-fold in CtS, GS and ChS, respectively, compared to control at day 14. A significant increase of N2O emission in all treatments occurred within 5 days and then it was slightly increased until day 14. N2O emission was 2-fold higher in all manure-amended soils than that of control. Compared to day 1, inorganic N (NH4 + plus NO3 --N) content was highly increased in all four treatments at day 14. The increase rate was the highest in CtS treatment. Net N mineralization was increased by 4.0-, 2.4- and 2.9-fold in CtS, GS and ChS, respectively, compared to control. These results indicate that increase of NH3, CO2 and N2O gas emissions was positively related to high N mineralization.
Mineralization is an important biological process for conversion of organic nitrogen (N) to inorganic N which can be used by plants directly. To investigate the effect of different manures on soil mineralization, the soil amended with cattle (CtM), goat (GM), chicken manure (ChM) and pig slurry (PS) were incubated under in vitro condition and ammonium N (NH4 +-N), ammonification rate and ammonia emission were determined for eighty-four days. NH4 +-N was the highest in PS-amended soil for the whole experimental period. NH4 +-N in PS-amended soil was gradually decreased until day 84, whereas it was rapidly decreased for the first 14 days and then slightly increased until 84 days in ChM-, CtM- and GM-amended soil. The ammonification rate showed negative value for the first 14 days in all treatments. From day 14, ammonification rate started to increase in CtM- and ChM-amended soil, whereas it was maintained in GM- and PS-amended soil until day 84. The daily ammonia emission was the highest in PS-amended soil (41mg kg-1 d-1), followed by CtM-, ChM-, and GM-amended soil at day 1. It was gradually decreased until day 84 in all treatments. The total NH3 emission was the highest in PS-amended soil with 0.6 mg kg-1 for 84 days, while less than 0.1 mg kg-1 in three other plots. These results indicate that different manures showed different soil ammonification rate and NH3 emission.
The potential of nitrogen mineralization was studied by applying organic fertilizer to soil and incubating at 25℃ for 28 weeks. The organic fertilizers used in this experiment were oil-cake (CF-Ⅰ, CF-Ⅱ) and amino acid fertilizer (AAF-Ⅰ, AAF- Ⅱ). Accumulated mineralized nitrogen (N) fits the frist-order kinetics during incubation. The N mineralization potential (No) for organic fertilizers treated soil was highest at AAF-Ⅱ treatment with a value of 27.71 N mg/100g, then followed by CF-Ⅱ, AAF-Ⅰ, CF-Ⅰ. The pure N mineralization potential (N0 treatment - N0 control) for CF-Ⅰ, CF-Ⅱ, AAF-Ⅰ, AAF-Ⅱ were 2.55, 5.83, 3.66, 8.57 N mg/ 100g, respectively. The amount of N mineralized from organic fertilizers applied soil ranged from 46% to 61% of the total N content in organic fertilizer. The half-life (t1/2) of organic nitrogen in soil treated with oil-cake and amino acid fertilizer was 17-21 days. Therefore, half of nitrogen contained in oil-cake and amino acid fertilizer was mineralized after 3 weeks application.
A stabilization/solidification (S/S) process for lead (Pb) contaminated soils was evaluated using waste cow bone containing apatite like compounds. Soil samples obtained form firing range were treated with waste cow bone. The effectiveness of stabilization was evaluated based on the Korean Standard Leaching Test (KSLT) and soil pH. The leached concentration reduced with increased in dose of waste cow bone. Overall, the KSLT results showed that Pb concentration in soils are significantly affected by amount of waste cow bone. When soil amended with 20 % of waste cow bone, less than 0.1 mg/kg was leached, and soil pH was increased from 6.5 to 8.4. Same results were obtained when finer waste cow bone was applied. The reachable concentration of Pb in soil showed in inversely proportional to solid/liquid ratio. Aging periods indicate improving mix design was applied. Relatively high lead concentrations was observed at the first 1 days, however leaching profile are reduced significantly over time for all mix designs.