• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.23-28
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• 1997

A better understanding of nitrogen transformations in soils is essential to increase fertilizer nitrogen use efficiency. A laboratory incubation study was conducted to determine net mineralization and nitrification in selected Piedmont soils. Net mineralization and nitrification increased up to 60 days in the surface layers of Enon, Mecklenburg and Chewacla. After 60 days both processes declined up to 90 days incubation. In Wehadkee, mineralization and nitrification did not differ with incubation time. In all subsurface layers, mineralization and nitrification increased with time up to 90 days. Mineralization and nitrification differed among soils in surface and subsurface layers. These differences might be influenced by soil type related to amount of mineralization, soil aeration and nitrifying bacterial populations. A mineralization and nitrification was greater in surface layers than in subsurface layers.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.16-22
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• 1997

Determination of N mineralization and nitrification potentials of selected Piedmont soils of North Carolina requires a better understanding of the influences of incorporated plant residues. The net N mineralization and nitrification were significantly influenced by the soil types and by plant species. The net N mineralization and nitrification of soils mixed with plant residues were consistently increased with successional incubation periods. The net mineralization and nitrification ranged from $9.77{\mu}g/g$ to $143.80{\mu}g/g$, and from $5.31{\mu}g/g$ to $145.66{\mu}g/g$ during the incubation periods, respectively. The net N mineralization was more influenced by NO3-N than by NH4-N. Overall, the greatest proportions of net N mineralization and nitrification occurred in Chewacla and Wehadkee and lowest in Enon and Mecklenburg. For the plant residues, the net N mineralization and nitrification were observed to be lowest in corn and highest in soybean. In a low-input agricultural systems, soybean may be planted as cover crop which may improve the nitrogen status of selected Piedmont soils of North Carolina.