Independent observation of the effects
of agricultural management practices on soil organic carbon (SOC) with soil moisture
content (SMC) is essential to quantify their potential relationships for
sustainable ecosystems. Soil water retention studies and soil carbon stocks
have been mapped in some areas worldwide. However, few studies have been conducted
in the southeastern US, particularly in Mississippi.
The objectives of this research study were to collect soil samples from fields
chosen to be representative of the watersheds they are contained within,
analyze the soil samples for carbon content and soil moisture content, and
evaluate the relationship between SOC and different parameters (land use,
vertical distribution, temporal distribution, and soil moisture content). Field
sites were chosen based on their compositional similarity shared with the
watershed as a whole in the Town Creek watershed (TCW) and Upper Pearl River
watershed (UPRW) in Mississippi.
Monthly soil samples from different depths (6 inch, 12 inch, and 24 inch) were
collected from crop, pasture, and forest field areas. Soil samples were
analyzed using bench analysis, elemental analysis, and statistical analysis.
This study was able to demonstrate the SOC distribution in the soil layers
across all three land uses studied. It was also shown that there does seem to
be an interactive effect of parameters such as land use type, vertical
distribution, and time on carbon accretion within the soil. Results of this
study also determined that the near surface (6-in) layer was found to contain
significantly more carbon than either the 12 inch or 24 inch layers (p<0.01) across all field types. There
was found to be a high degree of variability within the soil moisture data and
correlation between SOC and SMC. It was found that carbon amount is not
influenced by SMC but SMC could be influenced by SOC.
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B. R. Wilson, T. B. Koen, P. Barnes, S. Ghosh and D. King, “Soil Carbon and Related Soil Properties along a Soil Type and Landuse Intensity Gradient, New South Wales, Australia,” Soil Use and Management, Vol. 27, No. 4, 2011. pp. 437-447.
S. M. Ogle, F. J. Breidt, M. D. Eve and K. Paustian, “Uncertainty in Estimating Land Use and Management Impacts on Soil Organic Carbon Storage for US Agricultural Lands between 1982 and 1997,” Global Change Biology, Vol. 9, No. 11, 2003. pp. 1521-1542.
K. Y. Chan, M. K. Conyers, G. D. Li, K. R. Helyar, G. Poile, A. Oates and I. M. Barchia, “Soil Carbon Dynamics under Different Cropping and Pasture Management in Temperate Australia: Results of Three Long-Term Experiments,” Soil Research, Vol. 49, No. 4, 2011. pp. 320-328. doi:10.1071/SR10185
E. G. Jobbágy and R. B. Jackson, “The Vertical Distribution of Soil Organic Carbon and Its Relation to Climate and Vegetation,” Ecological Applications, Vol. 10, No. 2, 2000, pp. 423-436.
M. S. Moran, C. D. Peters-Lidard, J. M. Watts and S. McElroy, “Estimating Soil Moisture at the Watershed Scale with Satellite-Based Radar and Land Surface Models,” Canadian Journal of Remote Sensing, Vol. 30, No. 5, 2004, pp. 805-826. doi:10.5589/m04-043
W. J. Rawls, Y. A. Pachepsky, J. C. Ritchie, T. M. Sobecki and H. Bloodworth, “Effect of Soil Organic Carbon on Soil Water Retention,” Geoderma, Vol. 116, No. 1-2, 2003, pp. 61-76. doi:10.1016/S0016-7061(03)00094-6
US Department of Agriculture, National Agricultural Statistics Service (USDA-NASS), “Mississippi County Data Livestock.United States Department of Agriculture (USDA),” 2011.