Laboratory measurements and modeling N mineralization potential in Virginia Coastal Plain agricultural, fallow, and forest soils

Files

TR Number

Date

2000

Journal Title

Journal ISSN

Volume Title

Publisher

American Society of Agricultural and Biological Engineers

Abstract

A long-term aerobic incubation and leaching technique was used to measure N mineralization of surface and subsurface soils (sandy loam) from agricultural,forest, and fallow sites in a Virginia Coastal Plain watershed. N mineralization potential was measured to refine models used to describe this process in a watershed-scale nutrient export assessment. Potentially mineralizable N (N-0) and reaction rate constants (k) were estimated using a first-order model and a nonlinear regression procedure. Large variations in cumulative N mineralized, N-0, and k, were found for the surface soils from agricultural areas. Forest soils had much higher potentially mineralizable N than agricultural soils. For subsurface soils, the differences among land uses were less variable than those observed for the surface soils. The first order model (single-pool approach) was adequate for predicting N mineralization in surface soils from agricultural and fallow areas, but less suitable for forest surface soils. Consideration of a double exponential (two-pool approach) model did not improve the performance of N mineralization prediction for forested or agricultural soils. Large variations occurred in the field-predicted values of mineralized N due to temperature and moisture ranges commonly occurring throughout the season. Variability in the N mineralization potential of soils in the watershed suggests that individual k and N-0 should be derived for soils with similar properties to obtain better predictions of N mineralization and thus N movement to groundwater.

Description

Keywords

Organic N, Inorganic N, Model, Land use, Nitrogen mineralization, Temperature, Moisture, Agricultural engineering

Citation

Shukla, S.; Mostaghimi, S.; Burger, J. A., "Laboratory measurements and modeling N mineralization potential in Virginia Coastal Plain agricultural, fallow, and forest soils," Transactions of the ASAE. VOL. 43(2): 315-325. (doi: 10.13031/2013.2707) @2000