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DOT Project Number:  90-00-LRTF-509

Fiscal Year:  2005

Award:  $25,000.00

Principal Investigator:  Dr. Mahdi Al-Kaisi, Assistant Professor, Department of Agronomy, Iowa State University, malkaisi@iastate.edu

Other Project Participants:  Mark A. Licht, Extension Program Specialist, Iowa State University, and Beth E. Larabee, Research Associate, ISU Department of Agronomy. José Guzmán Research Assistant ISU Department of Agronomy

Research Report:

INFILTRATION RATES FOR NATIVE AND RECONSTRUCTED PRAIRIES ACROSS IOWA 
 Period covered by this report: 1 Jan 2000 through1 June 2006

EXECUTIVE SUMMARY

The objectives of this project were to (1) determine infiltration rate, bulk density, and soil carbon parameters of native prairie, newly reconstructed prairie, mature reconstructed prairie, turf grass, and brome grass and over different natural soil types and engineered soils and (2) determine infiltration rates, soil bulk densities, and soil carbon parameters under various species of vegetation and hill-slope features in central and south central Iowa.  In Story County three roadside reconstructed prairie sites were selected along Interstate 35.  In addition to the roadside reconstructed prairies, smooth bromegrass, bluegrass, and a native prairie remnant were selected as comparison sites.  All central Iowa sites were sampled in four replications.  In Jasper and Warren Counties, three reconstructed prairies were selected in addition to an agricultural field and native prairie as comparison sites.  Measurements at each site consisted of three replications at the summit, midslope, and toeslope landscape positions.  Overall, water infiltration at the Story County sites ranged from 0.15 to 0.28 cm min-1 in 2004.  The bluegrass treatment which was established in the 1970 had the highest water infiltration rate.  Infiltration rates for 2005 in the Jasper-Warren County area overall rates ranged from 0.12 to 0.25 cm min-1 with the highest rate in the 1998 reconstructed prairie.  In 2005 infiltration rates for the Jasper-Warren County sites ranged from 0.07 to 0.35 cm min-1 with the highest rate in the 1998 reconstructed prairie toeslope. Bulk densities to a 12.7 cm soil depth ranged from 1.03 to 1.21 g cm-3 in Story County for 2004 while bulk densities in the Jasper-Warren County area ranged from 0.83 to 1.17 g cm-3.  In 2005, bulk densities were determined to a 60 cm depth in Jasper and Warren Counties and ranged from 1.10 to 1.24 g cm-3.  Percent Soil Organic Carbon (SOC) to a 12.7 cm soil depth ranged from 2.20 to 3.89% in Story County in 2004 while SOC in the Jasper-Warren County area ranged from 1.69 to 3.77%.  In 2005, SOC were determined to a 60 cm soil depth in Jasper and Warren Counties and ranged from 0.94 to 3.76%.

INTRODUCTION

European migration into the mid-continent plains of the North America marked the demise of large prairie expanses.  Most immigrants were interested in the economic potential inherent in the prairie while very few were interested in other aspects of the prairie environment.  A small number of people have championed the need to preserve the rare remaining prairie remnants during the last 150 years (Conrad and Hess, 1998), but wide spread public interest in environmental quality and the preservation of habitat and unique ecosystems did not occur until the effects of DDT and other chemicals in the environment came to the nation’s attention (Carlson, 1962).  A multitude of entities have since been involved with preserving remaining prairie remnants or restoring and reconstructing prairies.  Prairie reconstructions and restorations serve a wide range of purposes including: improving soil and water quality, weed control, preserving genetic resources, wildlife habitat, and social values (Thompson, 1992).  The objectives of this project were to investigate infiltration rates of native prairie, maturing reconstructed prairie, and brome grass and turf grass soils over different natural soil types as well as engineered soils and determine how bulk density and soil carbon parameters of the native prairie, mature reconstructed prairie, turf grass, and brome grass correlate with infiltration rate.  This research project presents the ability to determine infiltration rates, soil bulk densities, and soil carbon parameters under various species of grass forming vegetation and hill-slope features in central and south central Iowa.

MATERIALS AND METHODS

This study was conducted in Story, Jasper, and Warren Counties in Iowa during 2004 and 2005.  The Story County sites were located along Interstate 35 (I-35).  They are classified as typic Udorthents and typic Hapludolls (Appendix A).  The I-35 roadside sites are on engineered soils and the rest area brome and the Ames High Prairie soils were formed in glacial till under native prairie vegetation (Dewitt, 1978).  Engineered soils have been drastically altered by: excavation, additions of specific fill materials, dewatering, repeated vigorous compaction, and other construction techniques (Schroeder et al., 2004).

The prairie reconstruction sites within Neal Smith National Wildlife Refuge in Jasper County included Mahaska, Tama, and Otley soils which are classified as aquic Argiudolls, typic Argiudolls, and typic Argiudolls, respectively (Appendix A).  The Rolling Thunder native prairie is located in Warren County was located on a Sharpsburg soil classified as typic Argiudolls (Appendix A).  The soils in both Jasper and Warren Counties formed in loess under a native vegetation of tall prairie grasses (Bryant and Woster, 1978; Nestrud and Woster, 1979).

EXPERIMENTAL DESIGN

In 2004, along the I-35 corridor in Story County, Iowa, four completely randomized plots were selected at each treatment consisting of an area with a known planting history, suite of plants species, and management strategy (Appendix A).  The Story County sites consisted of roadside reconstructed prairie, bluegrass, bromegrass, and native prairie using four replications 40 feet apart in an approximate square. The Jasper-Warren County sites in 2005 consisted of three reconstructed prairie, native prairie, and corn-soybean agriculture with 9 plots per site (three replications at each of three hill-slope positions).  Water infiltrations were conducted and carbon, bulk density, and global positioning points were also taken.

MEASUREMENTS AND ANALYSIS

Global positioning coordinates were determined for all plots and all sites by a Transplant IGPSJ unit with external antenna (Transplant GPS, Byron MN) (Appendix B).[1]  Plant inventories were supplied by the Iowa Department of Transportation, Warren County Conservation Board, Neal Smith National Wildlife Refuge, and the Nature Conservancy and were supplemented by direct observation (Appendix C).

Infiltration rate was measured using a Cornell Sprinkle Infiltrometer (Cornell University, Ithaca NY) (Ogden et al., 1997) (Fig. 1).  This system consisted of a portable rainfall simulator placed on a single 24.1 cm inner diameter ring inserted 7 cm into the soil.  The ring is equipped with an overflow tube to determine the time to runoff and runoff rate.  Rainfall simulator intensity rates of 0.4 to 0.5 cm min-1 were used.

Bulk density samples were collected during 2004 using a 1.85 cm diameter probe to a depth of 12.7 cm.  Whole cores were used for bulk density.  Bulk density samples were collected in 2005 using a 1.85 cm diameter soil probe to a depth of 60 cm.  These cores were divided into increments of 0-7.5, 7.5-15, 15-30, 30-45 and 45-60 cm. Each sample was oven dried at 105 ºC for 24 hours and weighed.  Bulk density was calculated with the formula;

BD = ODW/V,

Where; BD is bulk density (g/cm3), ODW is soil oven dry weight (g), and V is soil volume (cm3) determined by the radius (r) of the probe and the length of the core (L) where V = πr2*L (Blake and Hartge, 1986).

Soil organic carbon samples in 2004 were taken using a 1.85 cm diameter soil probe to a soil depth of 12.7. Eight to12 sub-samples were collected for each increment per plot.  Soil organic carbon samples in 2005 were taken using a 1.85 cm diameter soil probe to a soil depth of 60. The cores were divided into increments of 0-7.5, 7.5-15, 15-30, 30-45 and 45-60 cm. Eight to12 sub-samples were collected for each increment per plot.  All SOC samples were 2mm sieved and air dried. Total SOC was determined by dry combustion with a LECO TruSpec CHN analyzer (LECO, St. Joseph, MI).

RESULTS AND DISCUSSION

Overall, water infiltration in 2004 at the Story County sites ranged from 0.15 to 0.28 cm min-1 (Appendix D). The bluegrass treatment that was established in the 1970 had the highest water infiltration rate of 0.28 cm min-1 while the I-35 roadside reconstructed prairies had infiltration rates ranged from 0.15 to 0.19 cm min-1.  The Ames High Prairie and the Rolling Thunder native Prairie both had an average infiltration rate of 0.17 cm min-1.  The reconstructed prairies at Neal Smith National Wildlife Refuge ranged from 0.12 to 0.25 cm min-1.  The high infiltration rate in the bluegrass treatment was likely due to buried concrete (construction waste) found at a 45 cm soil depth with exploratory soil cores while the row crop site was lowest.  There were no significant differences between sites (Figs. 3 and 4).

In 2005, only the Jasper-Warren county sites were evaluated (Appendix D).  Overall, infiltration rates ranged from 0.07 to 0.35 cm min-1.  The 2003 reconstructed prairie had the lowest average infiltration rate of 0.15 cm min-1 with a range of 0.13 to 0.19 cm min-1 while the 1998 reconstructed prairie and the 1993 reconstructed prairie (Fig. 6) had relatively higher average infiltrations of 0.21 and 0.23 cm min-1 and ranges of 0.10 to 0.35 and 0.22 to 0.24 cm min-1, respectively.  There were significantly lower infiltrations on the 1998 reconstructed prairie’s summit and midslope, and the Rolling Thunder native prairie’s summit and midslope than infiltration rates of similar positions of other plots (Figs. 6).

When slope positions were examined, no significant differences in infiltration rates were found for midslopes.  Rolling Thunder native prairie summits infiltration rates were significantly lower than those of all other sites and toeslope position varied widely with the 1998 reconstructed prairie had significantly higher infiltration rate than all other sites.  The 2003 reconstructed prairie, the native prairie and the row crop field were statistically similar (Fig. 7).

All soil bulk densities were lower than 1.35 g cm-3 for Story, Jasper, and Warren County sites in 2004 (Appendix C). Bulk densities to a 12.7 cm depth ranged from 1.03 to 1.21 g cm-3 in Story County for 2004, while bulk densities in the Jasper-Warren County area ranged from 0.83 to 1.17 g cm-3.  The Rolling Thunder native prairie had a significantly lower bulk density than the Highway 210 or the 1993 reconstructed prairie which were also significantly lower than those of all other sites.  The 13th Street site and the row crop site had significantly higher bulk densities than the reconstructed prairies, but were not significantly different from one another regardless of planting date (Fig. 8).  Bulk density followed the predicted pattern with the highest bulk density in the agricultural field and decreasing in all the reconstructed prairies with length of time.  Soils that develop under grass species have lower bulk densities due to large fibrous root systems that contribute to organic matter within the soil.  Additionally, for all treatments there was no correlation between bulk density and water infiltration rates in 2004 (Fig. 12).

In 2005, only the Jasper-Warren County sites were evaluated.  Bulk density ranged from 1.09 to 1.24 g cm-3 (Appendix D).  The row crop field had a significantly higher bulk density at the 15 cm soil depth than all other sites and the Rolling Thunder native prairie had significantly lower bulk densities than all other sites.  The reconstructed prairies had similar bulk densities regardless of planting date (Fig. 9).  There were significant differences in bulk density over the 60 cm soil depth as the 2003 reconstructed prairie bulk density was significantly higher than those of all other sites.  There was no significant correlation between bulk density and infiltration rates in 2005 (Fig. 14).

In 2004, SOC was evaluated for the top 12.7 cm soil depth.  Soil organic carbon averages ranged from 1.69 to 3.77% (Appendix C).  Among the Story County sites, SOC ranged from 2.20 to 3.89% and was significantly higher for the E-18 HWY site than all others, while the Rest Area brome was significantly lower than all other sites.  The Rest Area bluegrass was significantly higher than Highway 210, Highway E-18, and the Rest Area brome.  The Jasper-Warren County sites also differed significantly.  Rolling Thunder native prairie was significantly higher than all other sites.  The 1998 and 2003 reconstructed prairies were significantly lower than all other sites while the agricultural field, 1993 reconstructed prairie and the roadside reconstructed prairie were not significantly different from each other but significantly different from the Rolling Thunder native prairie and the 1998 and 2003 reconstructed prairies (Fig. 11).

In 2005, SOC were determined to a 60 cm soil depth in Jasper and Warren Counties and ranged from 0.94 to 3.76%.  There were no significant differences between slope positions for the agricultural field or the 1998 and 2003 reconstructed prairies. Within the 1993 reconstructed prairie site, midslope SOC was significantly lower than either summit or toeslope positions (Fig. 11).  Rolling Thunder native prairie toeslope position was significantly higher SOC than either summits or midslopes.  Soil organic carbon ranged from 1.20 to 3.76% to a 15 cm soil depth.  There were no significant differences between landscape positions with sites for the agricultural field, Rolling Thunder native prairie and the 1998 reconstructed prairie.  Within the 1993 reconstructed prairie, the summit position was significantly higher than either midslope or toeslope.  Within the 2003 reconstructed prairie the midslope SOC was significantly lower than both the summit and toeslope (Fig. 11).

CONCLUSIONS

The Story County sites, bluegrass and bromegrass generally improved water infiltration rates as compared to roadside reconstructed prairies.  Water infiltration rates for the reconstructed roadside prairies were typically quite variable.  At all sites the infiltration variability could not be explained by the bulk density, however the plant suites also varied widely by treatment.  The prairie remnants displayed the most diverse plant populations followed by the reconstructed prairies.  Roadside reconstructed prairies in general were less diverse than reconstructed prairies, while the monoculture grass species and agricultural field displayed no plant species diversity.  Additionally, all of the roadside reconstructed sites were established on engineered soils.  Engineered soils are drastically altered by excavation, additions of specific fill materials, dewatering, repeated vigorous compaction, or other construction techniques that will have significant impact of soil properties including infiltration rate.  The natural soil physical properties of roadside soils have been compromised and no longer possess the natural condition.  Redevelopment of significant soil structure may take a longer time period and the establishment of a wide range of plant species.

[1]Trade names and product lines are used for the benefit of readers and do not imply endorsement by Iowa State University over comparable products.

FIGURES


Figure 1


 

 

APPENDICES (pdf)

 

REFERENCES

Bryant, A.A., J.R. Woster, 1978. Soil Survey of Warren County, Iowa USDA-SCS. U.S. Government Printing Office, Washington, D.C.

Blake, G.R., K.H. Hartge, 1986. Bulk Density. P. 363-375 In A. Kluste. Methods of Soil Analysis Part. 1 Physical and Mineralogical Methods 2nd ed. ASA and  SSSA Madison WI.

Carlson, R., 1962. Silent Spring. Houghton-Mifflin Co. Boston, Massachusetts.

Conrad, R. and S. Hess, 1998.  Tallgrass Prairie national Preserve Legislative History, 1920-1996. National Park Service Midwest Support Office, Omaha, Nebraska.

Dewitt, T.A., 1978. Soil Survey of Story County, Iowa USDA-SCS. U.S. Government Printing Office, Washington, D.C.

Drohan, P.J., E.J. Ciolkosz and G.W. Petersen, 2003.  Soil Survey Mapping Unit Accuracy in Forested Field Plots in Northern Pennsylvania. Soil Sci. Soc. Am. J.67:208-214. 

Lin H.S., K.J. McInnes, L.P. Wilding, and C.T. Hallmark, 1999.  Effects of Soil Morphology on Hydraulic Properties: I.Quantification of Soil Morphology.  Soil Sci. Soc. Am. J. 63:948–954 (1999).

Nestrud L.M., J.R. Woster, 1979. Soil Survey of Jasper County, Iowa USDA-SCS. U.S. Government Printing Office, Washington, D.C.

Ogden, C.B., H.M. van Es, and R.R. Schindelbeck. 1997. A simple rainfall simulator for measurement of soil infiltration and runoff. Soil Sci. Soc. Am. J. 61:1041-1043. 

Schroeder, W.L., S.E. Dickenson, and D.C. Warrington (ed.) 2004. Stress Analysis and Engineering Properties p. 59-82. In Soils in Construction., Prentice Hall, New Jersey

Thompson, J.R. 1992. Prairies, Forests and Wetlands. The Restoration of Natural Landscape Communities in Iowa.  University of Iowa Press, Ames, Iowa.

van Es, H.M., C.B. Ogden, R.L. Hill, R.R. Schindelbeck, and T. Tsegaye. 1999.  Integrated Assessment of Space, Time, and Management-Related Variability of Soil Hydraulic Properties. Soil Sci. Soc. Am. J. 63:1599-1608