Journal ArticleDOI
Nitrogen Mineralization Potentials of Soils
George Stanford,S. J. Smith +1 more
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In this paper, a 30-week period at 35C, using incubation intervals of 2, 2, 4, 6, 8, and 8 weeks, was used to determine the net mineralization of 39 widely differing soils.Abstract:
Net mineralization of N in 39 widely differing soils was determined over a 30-week period at 35C, using incubation intervals of 2, 2, 4, 4, 4, 6, and 8 weeks. Mineral N was leached from the soils before the first incubation and following each of seven incubations by means of 0.01M CaCl₂ and a minus-N nutrient solution. Soil water contents were adjusted by applying suction (60 cm Hg), and losses of water during incubation under aerobic conditions were negligible. With most soils, cumulative net N mineralized was linearly related to the square root of time, t½. The pH of soils changed very little in the course of 30 weeks' incubation. Because of the generally consistent results, the data were employed in calculating the N mineralization potential, Nₒ, of each soil, based on the hypothesis that rate of N mineralization was proportional to the quantity of N comprising the mineralizable substrate. Values of Nₒ ranged from about 20 to over 300 ppm of air-dry soil. The fraction of total N comprising Nₒ varied widely (5 to 40%) among soils. Mineralization rate constants did not differ significantly among most of the soils. The most reliable estimate of the rate constant, k was .054 ± .009 week⁻¹. The time required to mineralize one-half of Nₒ, t½, was estimated to be 12.8 ± 2.2 weeks. Results suggest that the forms of organic N contributing to Nₒ were similar for most of the soils.read more
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Cold and hot water–extractable organic matter as indicators of litter decomposition in forest soils
TL;DR: In this paper, the composition of cold and hot water-extractable organic matter was investigated in the O horizons (Oi, Oe, Oa) of a 170 y old beech stand (Fagus sylvatica) in the Ore Mtns., SE Germany.
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A rapid procedure for estimating nitrogen mineralization in manured soil.
TL;DR: In this article, the authors compared results from a recently proposed rapid laboratory procedure with: (1) long-term N mineralization under standard laboratory conditions, and (2) actual forage N uptake from soil receiving dairy cattle (Bos taurus) manure in a 2-year field study.
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A Grassland Nitrogen Flow Simulation Model
J. O. Reuss,G. S. Innis +1 more
TL;DR: A dynamic simulation model of nitrogen flow in a grassland ecosystem has been developed that includes a simple producer-decomposer submodel, but the nitrogen sections have also been incorporated into the ELM model.
Journal ArticleDOI
Mineralization and leaching of phosphorus from soil incubated with surface-applied and incorporated crop residue
Andrew N. Sharpley,S. J. Smith +1 more
TL;DR: In this paper, the effect of placement (surface or incorporation) of residue of six crop types (alfalfa, L., corn, L.; oat, L, peanut, L; soybean, (L) Merr.; wheat, L.) on the mineralization and leaching of P from eight soils was investigated.
Journal ArticleDOI
Nitrogen mineralization dynamics following the establishment of a loblolly pine plantation
TL;DR: The USDA Forest Service initiated a national study in the early 1990s to examine the effects of organic matter removal, compaction, and vegetation control on tree growth and soil processes at sever...