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Gas chromatographic patterns of organic solvent-soluble constituents present in alkaline hydrolysates of organic matter from soils underlying native range and crested wheatgrass were qualitatively, but not quantitatively similar. The peak at 222°C or with a retention time of about 31 min was identified as bis(2ethylhexyl) phthalate. Larger quantities of the extracted compounds were obtained from the native range than from the crested wheatgrass soils. Fifty years was not long enough for organic matter of soil cultivated for only 5 years to regain its original quantitative chemical composition under the prevailing climatic conditions. Crested wheatgrass (Agropyron cristutum Gaertn.) is a useful pasture grass for the revegetation of abandoned or marginal cropland, primarily because of increased yield compared to native range (Hull and Klomp 1966; Smoliak et al. 1967). In Western Canada, however, environmentalists are demanding an increasingly greater role in the decision-making processes affecting rangelands. They consider the breaking up of native range and the subsequent seeding of cultivated forage species such as crested wheatgrass to be destructive and irreversible. To counteract these sentiments, an understanding of the long-term effects of crested wheatgrass on soil characteristics is desirable. About 50 years after seeding, soil under crested wheatgrass stands appeared to be evolving toward an equilibrium somewhat different from that under adjacent native range. Differences were noted in such factors as bulk density, waterstable aggregates, total organic C, extractable organic C, polysaccharides, and moisture retention (Dormaar et al. 1978). Soil organic matter is related to all of these characteristics. Other characteristics of soil organic matter, such as certain solvent-soluble constituents, are responsible for part of the cation exchange capacity of the soil (Schnitzer and Gupta 1965) or are suggested to influence aggregation (Griffiths and Bums 1972). Authors are soil scientist, range ecologist, and range ecologist, respectively, Research Station, Agriculture Canada, Lethbridge, Alberta, Canada TlJ 4Bl. Manuscript received November 17, 1978. JOURNAL OF RANGE MANAGEMENT 33(2), March 1980 The purpose of this study was to compare organic solventsoluble constituents present in alkaline hydrolysates of soil organic matter developed under native range and adjacent stands of 40to 49-year-old stands of crested wheatgrass. Material and Methods Four pairs of plots, three pairs consisting of abandoned cropland seeded to crested wheatgrass nearly 50 years ago and adjoining range of the Mixed Prairie type (Sites 1, 2, and 4) and one pair where the native range was also on abandoned cropland (Site 3), were selected for the study. These sampling sites were the same as those described in previous studies (Smoliak et al. 1967; Dormaar et al. 1978). Five 500-g soil samples were collected on October 20, 1976, from the Ah horizon at the four comers and the center of each sampling site, air-dried, ground to pass a l-mm screen, and mixed to give one composite sample per site. From each of the eight composite samples, 100 g were extracted in a Soxhlet apparatus for 24 hr with a mixture of ethanol-benzene (1: 1) to eliminate fats and waxes (Dormaar et al. 1978). A 40-g subsample of this extracted soil was then hydrolyzed in 1,500 ml of 4% NaOH for 4 hr at 90°C under nitrogen to prevent possible antoxidation reactions (Morita 1965), cooled, acidified with HCl, and fractions presumably containing either phenolic or carboxylic acids, obtained (Burchfield and Storm 1962; Morita 1965). (The diethyl ether should be of “distilled in glass” grade thereby eliminating the preservative 2,6-ditert-butyl-6methylphenol.) Aliquots from these two extracts were injected onto a 1 m X 3.1 I.D. mm stainless steel column packed with 5% FFAP on 60-80 mesh GasChrom Q in a Hewlett Packard 57 10A gas chromatograph (gc). Controls were run in which the solvents with no soil sample were put through the entire procedure and then gas chromatographed. As the sample emerged, the components were detected by a flame ionization detector and recorded on a Hewlett Packard 3373B integrator with chart speed of 0.64 cm/min. The operating conditions were: N,-flow rate of 30 ml/min; column temperature program from 100 to 250°C at a rate of 4”C/min; injection port temperature, 200°C; and detector temperature, 300°C. To deal with the more volatile compounds in the extracts, the samples were not methylated. Materials representing major peaks were eluted from the gc column, collected in capillary tubes, and analyzed by mass spectrometry (Dupont mass spectrometer, model 2 l-49 1) and infrared spectrophotometry (Perkin-Elmer infrared spectrophotometer, model 457). The column temperature program

Organic Solvent-Soluble Organic Matter from Soils Underlying Native Range and Crested Wheatgrass in Southeastern Alberta, Canada