Effects of aspects and seasons on the soil enzyme activities in a temperate forest soil

Dowon Lee, Hojeong Kang, He-Jin Lee and Sinkyu Kang*

Department of Environmental Planning, Graduate School of Environmental Studies, Seoul National University, Seoul 151-742, Korea

Phone number : +82-2-880-5650

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E-mail : kangsk@plaza1.snu.ac.kr

Soil enzyme activities (dehydrogenase, urease, phosphatase, and arylsulphatase) in a temperate forest soil were studied in relation to aspects and seasons. The activities were determined in northern aspect, southern aspect, and ridge in autumn and spring, 1994 and 1995. Dehydrogenase, urease, phosphatase, and arylsulphatase activities varied 1.8 - 18.5 Ռg INT-formazan g-1 h-1, 45.4 - 347.0 Ռg NH4+ g-1 h-1, 0.9 - 4.5 mmole PNP g-1 h-1 , and 0.7 - 2.6 mmole PNP g-1 h-1 , respectively. In general, higher enzyme activities were found in the northern aspect than the southern aspect. The differences seem to be caused by the chemical properties of the sites. Two patterns are discernable related to seasonal variations. Dehydrogenase and urease exhibited higher activities in spring than autumn, suggesting that temperature might be one of the major controlling factors. In contrast, higher activities were detected in autumn for phosphatase and arylsulfatase activities. It is speculated that litterfall production affected the enzyme activities substantially. Urease activity exhibited a significant negative correlation with ammonium content, indicating that the enzyme production might be controlled by nitrogen availability in the soil.