Soil Carbon and Nitrogen Dynamics During Conversion of Agricultural Lands to Natural Vegetation in Central Korea

Abstract

Changes in land use can affect the distribution and cycling of soil organic matter and nutrients. Soil organic carbon (C) and nitrogen (N) concentrations, soil CO 2 evolution, litter decomposition, and soil N availability under the three types of conversion of agricultural lands to natural vegetation (rice field conversion to forest, crop field conversion to shrub, and indigenous forest) in central Korea after 20 years of fallow were compared. There was no significant change in soil organic C and N concentrations among the three types at the three soil depths, and soil organic C and N increases were confined to the topsoil (0 -10 cm). Soil CO 2 evolution tracked seasonal soil temperature, however, there was no difference among conversion types. Annual soil CO 2 evolution (Mg CO 2 /ha/yr) was 36:0^3:7 for the rice field conversion to forest site, 33:8^4:1 for the crop field conversion to shrub site, and 40:7^4:1 for the indigenous forest site, respectively. After decomposing for one year, 55.8% for the rice field conversion site, 64.9% for the crop field conversion site, and 66.3% for the indigenous forest site of the original leaf litter mass remained. The soil moisture condition seemed to limit the rate of decomposition in the study area. Resin NO 2 3 -N concentration was higher at the rice field conversion site.

Effect of Organic Inputs on Strength and Stability of Soil Aggregates Associated Organic Carbon Concentration under Rice-Wheat Rotation in Indo-Gangetic Plain Zone of India

“…Since soil BD has been shown to be inversely related to SOM (Son et al, 2003;Diana et al, 2008), where increasing SOM generally decreases soil BD by adding additional pore space without adding much additional mass, crop rotations with a large frequency of highresidue-producing crops that are managed using cultural practices that return crop residues to the soil could consequently at least maintain a near-surface soil BD that is favorable for gas exchange, water infiltration, and plant growth.…”

Soil respiration and FDA hydrolysis following conversion of abandoned agricultural lands to natural vegetation in Central Korea

“…No soil moisture measurements were made in January and February because the soils were frozen. Soil respiration was measured daily during a 4-h period (11:00 to 15:00), using an infrared gas analyzer (EGM4; PP systems, UK) and a soil respiration chamber (15 cm inside diameter), as described by Son et al (2003). Daily rates were calculated by assuming that the measured hourly rates represented the entire day.…”

“…All three sites are composed of same bedrock and have a southern aspect, but they differ slightly in their slopes, with RF being relatively flat while CS and IF are located on gentle slopes. The concentrations (%) of soil organic C and nitrogen (N) at 0 to 10 cm deep are 3.26 and 0.10 for RF, 2.70 and 0.08 for CS, and 3.35 and 0.10 for IF, respectively (Son et al, 2003). A more detailed site description has been published previously (Chung et al, 1998;Son and Lee, 2001 ;Son et al, 2003).…”

“…The concentrations (%) of soil organic C and nitrogen (N) at 0 to 10 cm deep are 3.26 and 0.10 for RF, 2.70 and 0.08 for CS, and 3.35 and 0.10 for IF, respectively (Son et al, 2003). A more detailed site description has been published previously (Chung et al, 1998;Son and Lee, 2001 ;Son et al, 2003).…”

“…These changes can influence key biogeochemical rates, thereby altering soil respiration and other soil processes. Nevertheless, information is very limited concerning these changes in soil microenvironments and C dynamics following this conversion (Aweto, 1981;Knops and Tilman, 2000;Post and Kwon, 2000;Son and Lee, 2001 ;Son et al, 2003).…”