In order to estimate nitrogen (N) mineralization rate of
livestock manure compost (LMC) applied to the soil. This
experiment was invested throughout incubation level test during six weeks. We used two different textured soils. One soil was silty loam soil collected from sea-reclaimed land soil located at Saemangeum, another soil was clay loam soil collected from sea-reclaimed soil located beside Yeongsan River. Both of soils was controlled in adjustment of EC levels at which former was at 3.5 and 12 dS m-1 and latter was at 3.7 and 9 dS m-1 respectively, and the soils were well mixed with LMC at 1, 2, and 3% levels based on soil weight basis, then we had monitored N mineralization rate, maintaining 25℃ of air temperature in incubator and field capacity of soil moisture content during six weeks.
It was estimated that amount of NH4 +-N was very low and
maintained from one to six weeks after application of LMC.
Because ammonia volatilization mineralized from LMC in soil of which initial pH was at over 7.5. NO3 --N contents in all soils was increased depending on increase level of LMC application rate. NO3 --N contents mineralized in the soil were maximized at three to four weeks after application of LMC, and then, the contents were decreased rapidly. Total inorganic nitrogen content in silty loam soil collected at Saemanguem was high with high EC level of soil treatment whereas, its contents in clay loam soil collected at Yeongsan River was high with low EC level of soil treatment. It was identified that soil EC did not influenced on N mineralization rate significantly in this experiment. We had monitored dehydrogenase content to supporting the result of inorganic nitrogen content mineralized during incubation periods, but both of the content was similar in rate. After five to six weeks during the period, on the other hand, amount of dehydrogenase was maintained or increased rather than those amount of inorganic nitrogen decreased rapidly, due to N immobilization with microbial activities in soil. It was estimated that amount of NO3 --N in all soil was
increased with decrease of pH values resulted in nitrification process during incubation period and the soil pH was somewhat increased by immobilization processed with microbial activities after three to four weeks.