Soil Depth and Changes in Dry Mass and Competitive Intensity of Two C4 Grasses


The presence of grassland biomes and species cannot be predicted by examining bottom up causes such as precipitation and temperature. Top down causes including herbivory and fire seem to be major controlling aspects with other factors secondary. We examined soil depth and competitive ability of two North American C4 grasses in a greenhouse experiment. Changes in dry mass were determined and competitive intensity was calculated for both species. Species were grown separately or together in pots 30, 90, or 180 cm deep. When grown in monoculture, Schizachyrium scoparium total and belowground dry mass increased from the 30 to 90 cm depth, with no further significant increase from 90 to 180 cm. Aboveground dry mass did not increase significantly with depth. Total dry mass of Buchloe dactyloides increased significantly with depth when grown in monoculture. Aboveground dry mass increased from 30 to 90 cm depth but not from 90 to 180 cm. Belowground dry mass of B. dactyloides did not increase significantly with depth. In 180 cm pots, 53% of S. scoparium root dry mass was in the top 30 cm; 74% of B. dactyloides root dry mass was in the top 30 cm. Roots of B. dactyloides were not found deeper than 90 cm. Aboveground dry mass of S. scoparium was not different in mixture or monoculture at any depth. Buchloe dactyloides aboveground dry mass in mixture was significantly lower than monoculture at the 30 cm depth, but not at 90 or 180 cm. The greatest competitive intensity was in the shallow soil pots. Soil depth could partially explain mosaics found in C4 grasslands where both species were found together with S. scoparium on deeper soils and B. dactyloides on shallower soils.

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J. Bush and O. Auken, "Soil Depth and Changes in Dry Mass and Competitive Intensity of Two C4 Grasses," American Journal of Plant Sciences, Vol. 5 No. 1, 2014, pp. 138-147. doi: 10.4236/ajps.2014.51018.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] M. J. Barbour, J. H. Burk, W. D. Pitts, F. S. Gilliam and M. W. Schwartz, “Terrestrial Plant Ecology,” Benjamin/ Cummings, Menlo Park, 1999.
[2] O. W. Van Auken, “Causes and Consequences of Woody Plant Encroachment into Western North American Grasslands,” Journal of Environmental Management, Vol. 90, No. 10, 2009, pp. 2931-2942.
[3] M. Begon, C. R. Townsend and J. L. Harper, “Ecology: From Individuals to Ecosystems,” Blackwell, Malden, 2006.
[4] T. Smith and R. Smith, “Elements of Ecology,” 8th Edition, Benjamin Cummings, New York, 2012.
[5] S. T. A. Pickett and P. S. White, “The Ecology of Natural Disturbance and Patch Dynamics,” Academic Press, Orlando, 1985.
[6] P. B. McEvoy, N. T. Rudd and C. S. H. Cox, “Disturbance, Competition, and Herbivory Effects on Ragwort Senecio Jacobaea Populations,” Ecological Monographs, Vol. 63, 1993, pp. 55-75.
[7] E. J. Cohn, O. W. Van Auken and J. K. Bush, “Competitive Interactions between Cynodon dactylon and Acacia smallii Seedlings at Different Nutrient Levels,” American Midland Naturalist, Vol. 121, No. 2, 1989, pp. 265-272.
[8] J. F. Cahill Jr. and B. B. Casper, “Canopy Gaps Are Sites of Reduced Belowground Plant Competition in a Productive Old Field,” Plant Ecology, Vol. 164, No. 1, 2002, pp. 29-36.
[9] N. Mazia, P. M. Tognetti and E. D. Cirino, “Patch Identity and the Spatial Heterogenity of Woody Encroachment in Exotic Dominated Old-Field Grasslands,” Plant Ecology, Vol. 214, No. 2, 2013, pp. 255-266.
[10] J. K. Bush and O. W. Van Auken, “Light Requirements of Acacia smallii and Celtis laevigata in Relation to Secondary Succession on Floodplains of South Texas,” American Midland Naturalist, Vol. 115, No. 1, 1986, pp. 118-122.
[11] O. W. Van Auken and R. J. Lohstroh, “Importance of Canopy Position for the Growth of Celtis Laevigata Seedlings,” Texas Journal of Science, Vol. 42, 1990, pp. 83-89.
[12] J. K. Bush and O. W. Van Auken, “Competition between Schizachyrium scoparium and Buchloe dactyloides: The Role of Soil Nutrients,” Journal of Arid Environments, Vol. 74, No. 1, 2010, pp. 49-53.
[13] W. J. Bond, “What Limits Trees in C4 Grasslands and Savannas?” Annual Review of Ecology, Evolution and Systematics, Vol. 39, 2008, pp. 641-659.
[14] E. J. Chaneton, N. Mazia, W. B. Batista, A. G. Rolhauser and C. M. Ghersa, “Woody Plant Invasions in Pampa Grasslands: A Biogeographical and Community Assembly Perspective,” Elsevier, London, 2012.
[15] A. K. Knapp and T. R. Seastedt, “Detritus Accumulation Limits Productivity of Tallgrass Prairie,” BioScience, Vol. 36, 1986, pp. 662-668.
[16] D. S. Schimel, T. G. F. Kittel, A. K. Knapp, T. R. Seastedt, W. J. Parton and V. B. Brown, “Physiological Interactions along Resource Gradients in a Tallgrass Prairie,” Ecology, Vol. 72, No. 2, 1991, pp. 672-684.
[17] D. R. Lane, “Aboveground Net Primary Production across a Precipitation Gradient in the Central Grassland Region,” M.S. Thesis, Colorado State University, Colorado, 1995.
[18] E. D. Schulze, H. A. Mooney, O. E. Sala, E. Jobbagy, N. Buchmann, G. Bauer, J. Canadell, et al., “Rooting Depth, Water Availability, and Vegetation Cover along an Aridity Gradient in Patagonia,” Oecologia, Vol. 108, No. 3, 1996, pp. 503-511.
[19] R. B. Jackson, J. Canadell, J. R. Ehleringer, H. A. Mooney, O. E. Sala and E. D. Schulze, “A Global Analysis of Root Distributions for Terrestrial Biomes,” Oecologia, Vol. 108, No. 3, 1996, pp. 389-411.
[20] H. Walter, “Die Verbuschung, Eine Erscheinung der Subtropischen Savannengebiete, und Ihre Ukologischen Ursachen,” Vegetatio, Vol. 5-6, No. 1, 1954, pp. 6-10.
[21] O. W. Van Auken, J. K. Bush and D. D. Diamond, “Changes in Growth of Two C4 Grasses (Schizachyrium scoparium and Paspalum plicatulum) in Monoculture and Mixture: Influence of Soil Depth,” American Journal of Botany, Vol. 81, No. 1, 1994, pp. 15-20.
[22] J. Fargione and D. Tilman, “Niche Differences in Phenology and Rooting Depth Promote Coexistence with a Dominant C4 Bunchgrass,” Oecologia, Vol. 143, No. 4, 2005, pp. 598-606.
[23] J. Nippert and A. Knapp, “Linking Water Uptake with Rooting Patterns in Grassland Species,” Oecologia, Vol. 153, No. 2, 2007, pp. 261-272.
[24] J. Silvertown, “Plant Coexistence and the Niche,” Trends in Ecology & Evolution, Vol. 19, No. 11, 2004, pp. 605-611.
[25] J. G. Teer, J. W. Thomas and E. A. Walker, “Ecology and Management of White-Tailed Deer in the Llano Basin of Texas,” Wildlife Monographs, Vol. 15, 1965, pp. 3-62.
[26] G. L. Wolters, C. H. Sieg, A. J. Bjugstad and F. R. Gartner, “Herbicide and Fire Effects on Leafy Spurge Density and Seed Germination,” United States Department of Agriculture, Rocky Mountain Forest and Range Experiment Station, Fort Collins, 1994.
[27] S. C. Fritcher, M. A. Rumble and L. D. Flake, “Grassland Bird Densities in Seral Stages of Mixed-Grass Prairie,” Journal of Range Management, Vol. 57, No. 4, 2004, pp. 351-357.
[28] A. J. W. Woodward, S. D. Fuhlendorf, D. M. Leslie Jr. and J. Shackford, “Influence of Landscape Composition and Change on Lesser Prairie-Chicken (Tympanuchus pallidicinctus) Populations,” American Midland Naturalist, Vol. 145, No. 2, 2001, pp. 261-274.[0261:IOLCAC]2.0.CO;2
[29] J. B. Grace, “On the Measurement of Plant Competition Intensity,” Ecology, Vol. 76, No. 1, 1995, pp. 305-308.
[30] P. D. Steinberg, “Schizachyrium scoparium,” 2002.
[31] F. W. Albertson, “Ecology of Mixed Prairie in West Central Kansas,” Ecological Monographs, Vol. 7, No. 4, 1937, pp. 483-547.
[32] J. E. Weaver, “North American Prairie,” University of Nebraska Press, Lincoln, 1954, p. 185.
[33] D. S. Correll and M. C. Johnston, “Manual of the Vascular Plants of Texas,” The University of Texas at Dallas, Renner, 1979, p. 1881.
[34] J. E. Weaver, “Summary and Interpretation of Underground Development in Natural Grassland Communities,” Ecological Monographs, Vol. 28, No. 1, 1958, pp. 55-78.
[35] J. E. Weaver, “Effects of Different Intensities of Grazing on Depth and Quantity of Roots of Grasses,” Journal of Range Management, Vol. 3, No. 2, 1950, pp. 100-113.
[36] J. L. Howard, “Buchloe Dactyloides,” 1995.
[37] H. Hopkins, “Root Development of Grasses on Revegetated Land,” Journal of Range Management, Vol. 6, No. 6, 1953, pp. 382-392.
[38] F. B. Taylor, R. B. Hailey and D. L. Richmond, “Soil Survey of Bexar County, Texas,” United States Department of Agriculture, Soil Conservation Survey, Washington, DC, 1966.
[39] J. L. Harper, “Population Biology of Plants,” Academic Press, London, 1977, p. 892.
[40] W. Bohm, “Methods of Studying Root Systems,” In: W. D. Billings, F. Golley, O. L. Lange and J. S. Olson, Eds., Ecological Studies, Springer-Verlag, New York, 1979, pp. 247-248.
[41] A. Weigelt and P. Jolliffe, “Indices of Plant Competition,” Journal of Ecology, Vol. 91, No. 5, 2003, pp. 707-720.
[42] J. A. Sall, A. Lehman and L. Creighton, “JMP Start Statistics: A Guide to Statistics and Data Analysis Using JMP and JMP IN Software,” Duxbury Thomson Learning, Pacific Grove, 2001.
[43] K. D. M. McConnaughay and E. I. Newman, “Is Physical Space a Soil Resource?” Ecology, Vol. 72, No. 1, 1991, pp. 94-103.
[44] K. D. M. McConnaughay and F. A. Bazzaz, “The Relationship between Gap Size and Performance of Several Colonizing Annuals,” Ecology, Vol. 68, No. 2, 1987, pp. 411-416.
[45] K. D. M. McConnaughay, “Interactions among Colonizing Annuals: Is There an Effect on Gap Size?” Ecology, Vol. 71, No. 5, 1990, pp. 1941-1951.
[46] K. D. M. McConnaughay and F. A. Bazzaz, “The Occupation and Fragmentation of Space: Consequences of Neighboring Roots,” Functional Ecology, Vol. 6, No. 6, 1992, pp. 704-710.
[47] S. Fuhlendorf and F. Smeins, “The Influence of Soil Depth on Plant Species Response to Grazing within a Semi-Arid Savanna,” Plant Ecology, Vol. 138, No. 1, 1998, pp. 89-96.
[48] H. Walter, “Ecology of Tropical and Subtropical Vegetation,” Oliver & Boyd, Edinburgh, 1971.
[49] M. Huston, “A General Hypothesis of Species Diversity,” American Naturalist, Vol. 113, No. 1, 1979, pp. 81-101.
[50] B. D. Campbell, J. P. Grime, J. M. L. Mackey and A. Jalili, “The Quest for a Mechanistic Understanding of Resource Competition in Plant Communities: The Role of Experiments,” Functional Ecology, Vol. 5, No. 2, 1991, pp. 241-253.
[51] S. D. Wilson and D. Tilman, “Quadratic Variation in Old-Field Species Richness along Gradients of Disturbance and Nitrogen,” Ecology, Vol. 83, No. 2, 2002, pp. 492-504.[0492:QVIOFS]2.0.CO;2
[52] K. L. Reichhardt, “Succession of Abandoned Fields in the Shortgrass Prairie, Northeastern Colorado,” Southwestern Naturalist, Vol. 27, No. 3, 1982, pp. 299-304.
[53] D. P. Coffin and W. K. Lauenroth, “The Effects of Disturbance Size and Frequency on a Shortgrass Plant Community,” Ecology, Vol. 69, No. 5, 1988, pp. 1609-1617.
[54] G. W. Rehm, W. J. Moline and E. J. Schwartz, “Response of a Seeded Mixture of Warm-Season Prairie Grasses to Fertilization,” Journal of Range Management, Vol. 25, No. 6, 1972, pp. 452-456.
[55] F. Rauzi, “High Rates of Nitrogen Change Composition of Shortgrass Rangeland in Southeastern Wyoming,” Journal of Range Management, Vol. 31, No. 5, 1978, pp. 366-370.
[56] F. Rauzi, “Residual Effects of Phosphorus and High Rates of Nitrogen on Shortgrass Rangeland,” Journal of Range Management, Vol. 32, No. 6, 1979, pp. 470-474.
[57] C. E. Richard and E. F. Redente, “Nitrogen and Phosphorus Effects on Blue Grama and Buffalograss Interactions,” Journal of Range Management, Vol. 48, No. 5, 1995, pp. 417-422.
[58] O. W. Van Auken and J. K. Bush, “Influence of Plant Density on the Growth of Prosopis glandulosa var. glandulosa and Buchloe dactyloides,” Bulletin of the Torrey Botanical Club, Vol. 114, No. 4, 1987, pp. 393-401.
[59] R. S. Kalmbacher, F. G. Martin and J. E. Rechcigl, “Effect of N-P-K Fertilization on Yield and Tiller Density of Creeping Bluestem,” Journal of Range Management, Vol. 46, No. 5, 1993, pp. 452-457.
[60] P. O. Reardon and D. L. Huss, “Effects of Fertilization on a Little Bluestem Community,” Journal of Range Management, Vol. 18, No. 5, 1965, pp. 238-241.
[61] O. W. Van Auken, J. K. Bush and D. D. Diamond, “Changes in Species Biomass in the Coastal Prairie of Texas When Light and Nutrients Are Altered,” Canadian Journal of Botany, Vol. 70, No. 9, 1992, pp. 1777-1783.
[62] O. W. Van Auken, J. K. Bush and D. D. Diamond, “The Role of Light and Nutrients in Determining Dominance of Paspalum plicatulum Michx. and Schizachyrium scoparium (Michx.) Nash, Two C4 grasses,” Bulletin of the Torrey Botanical Club, Vol. 119, No. 4, 1992, pp. 401-406.
[63] B. L. Foster, “Establishment, Competition and the Distribution of Native Grasses among Michigan Old-Fields,” Journal of Ecology, Vol. 87, No. 3, 1999, pp. 476-489.

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