Nitrogen Mineralization and Nitrification in a Cretaceous Shale and Coal Mine Spoils

Abstract

Knowledge of rates and amounts of N mineralization in geologic strata is needed to predict N availability to plants when these materials are disturbed by mining or construction and left as surface or subsurface plant‐growth media. Laboratory incubations were conducted to determine ammonification and nitrification rates in a Cretaceous shale, two strip‐mine coal spoils, and a soil from a strip mine in northwestern Colorado. The total N concentration in the soil (1193 ppm), a vegetated spoil (1,083 ppm), and the shale (1112 ppm) were similar, while that of the fresh spoil was lower (730 ppm). No net N mineralization was measured in the shale, and less than 6 ppm NO3‐‐N accumulated in the fresh spoil during a 168‐day incubation. However, net mineralization of 49‐ppm NO3‐‐N was found in the vegetated spoil and 75‐ppm NO3‐‐N in the soil during the same incubation period.Nitrification of added NH4+ (60 ppm NH4+‐N) was measured in the shale, spoils, and soil. Accumulated levels of NO3‐‐N were 100 ppm in the vegetated spoil and 117 ppm in the soil after a 168‐day incubation. However, only 36‐ppm NO3‐‐N accumulated in the fresh spoil and no NO3‐‐N accumulated in the shale during the same incubation period.Rates and total amounts of CO2 evolution from the geologic materials resembled that from the soil, indicating considerable heterotropic microbial activity in these geologic materials. The addition of NH4+ did not significantly affect the rate or amount of CO2 evolution from the geologic or soil materials, indicating that heterotropic microorganisms were capable of using the forms of N present in the geologic materials.

Supply and Turnover of N, P and K in Reclaimed Coal Mine Waste in Scotland

“…For example, Reeder and Berg (1977), Palmer and Chadwick (1985) and Fyles and McGill (1987) all used air-dried spoil, whereas in this study fresh spoil was used. Similarly there are a number of incubation systems which have been used.…”

“…More commonly, the supply of N to plants by various treatments has been measured (Palmer andCnadwick 1985, Palmer et al 1986), as have N transformations such as mineralization and nitrification Cooper 1976, Reeder andBerg 1977).…”

Patterns of Denitrification in Reclaimed Minespoils in the Arid Southwest

“…5), indicating that nitrogen· processing in this site probably proceeds at a relatively high rate when environmental conditions are appropriate. Total soil nitrogen at this site is also relatively high, and mineral nitrogen pools are probably maintained through mineralizatio·n of fossil nitrogen in the reclaimed spoil material (Reeder and Berg 1977).…”

V Adose Zone Water and Crop Response to Poultry Litter Application on Reclaimed Surface Mine Land

“…This N is not as readily mineralizable as soil organic matter, so that it can not supply the N needed by plants for growth. Mineralization potential of indigenous N is higher in soils than in mine spoils (Reeder and Berg, 1977a;b;Reeder, 1985;Reeder and Sabey, 1987). Power et al, (1974) found that exchangeable NH 4 in certain shales could be readily nitrified but the extent of mineralization of small amounts of organic N in the same shales was minimal.…”

“…Power et al, (1974) found that exchangeable NH 4 in certain shales could be readily nitrified but the extent of mineralization of small amounts of organic N in the same shales was minimal. Lower rates of N mineralization should be expected due to the fact that N in geologic materials can be present in forms not available for microbial metabolism (Reeder and Berg, 1977a). In order for disturbed lands to achieve a healthy, working ecosystem, accumulation of biomass and nutrients must occur (Woodmansee et al, 1978).…”