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The Role of Rooting Strategies on Drought Tolerance of Maize Hybrids: A Controlled, Laboratory Study

Shilling, Matthew Eric
http://rave.ohiolink.edu/etdc/view?acc_num=osu1397224105

Abstract Details

2014, Master of Science, Ohio State University, Civil Engineering.
Understanding the complex processes that control soil water and rooting interactions in the vadose zone impacts the way we approach urban development, agriculture, and land use management. Complexities caused by heterogeneities in vadose zone characteristics can control not only hydrologic cycles, but ecologic and biogeochemical cycles as well. However, due to these heterogeneities and the difficulty of reliable subsurface measurements, the dominant processes of the vadose zone remain largely unknown. Small-scale differences in these vadose zone processes, such as infiltration, rooting behavior, nutrient mineralization, are often ignored in large-scale modeling, can have impacts at the watershed or ecosystem scale. As a result of increased climate variability, rainfall characteristics are expected to change worldwide. These variations in rainfall characteristics will present problems in agricultural areas that are dependent on a consistent supply of water. In the face of increasing water scarcity, the development of crop hybrids, that are resistant to drought, as well as other environmental stresses, is an important step in securing the long term viability of agriculture. The plasticity of root architecture to heterogeneities in the vadose zone in order to take advantage of these heterogeneities is largely unknown, but these processes can have a huge impact on a crops resistance to environmental stresses, such as drought. This study designs a controlled, small-scale experiment using two-dimensional tanks to study the early growth and root architecture of two maize hybrids, a drought tolerant and a drought susceptible hybrid. However the laboratory setup can easily be modified to study the vast array of uncertainties within the vadose zone. The maize hybrid study incorporated a variable intensity rainfall simulator, lighting and temperature control, soil moisture sensors, and soil coring to quantify root development. This study subjected the two hybrids to three rainfall regimes with varying rainfall depths. Additionally, the rainfall regimes followed either a natural rainfall distribution, with varying rainfall characteristics, or an irrigation style, with constant rainfall characteristics. On the whole, the drought tolerant hybrid rooted more than the drought susceptible, especially in the deep portion of the soil column. However, the behavior of the two species was most similar under drought conditions. Both species restricted their above ground growth and rooting during the drought conditions, but the reduction in above ground growth was more dramatic for the drought tolerant hybrid. This study compares the transpiration efficiency of the two hybrids based on soil moisture and spatial root development, and found the drought tolerant to be more efficient, although their efficiencies were again similar in the drought experiment. The similarities during the drought rainfall regime were likely due to a combination of slowed overall growth and the short growing cycle used in the study. Additionally, the experiment with a natural rainfall distribution created the deepest root growth, likely due to a higher soil moisture gradient temporally than the irrigation experiments. Due to the rooting strategy employed by the drought tolerant hybrid, a larger soil volume is explored and a higher root-weighted transpiration efficiency is achieved.
Gajan Sivandran, PhD (Advisor)
Ethan Kubatko, PhD (Committee Member)
Gil Bohrer, PhD (Committee Member)
168 p.
Civil Engineering; Environmental Engineering
Drought Tolerance; Maize Hybrids; Rooting Strategies; Rainfall Regimes

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Citations

  • Shilling, M. E. (2014). The Role of Rooting Strategies on Drought Tolerance of Maize Hybrids: A Controlled, Laboratory Study [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397224105

    APA Style (7th edition)

  • Shilling, Matthew. The Role of Rooting Strategies on Drought Tolerance of Maize Hybrids: A Controlled, Laboratory Study. 2014. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1397224105.

    MLA Style (8th edition)

  • Shilling, Matthew. "The Role of Rooting Strategies on Drought Tolerance of Maize Hybrids: A Controlled, Laboratory Study." Master's thesis, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397224105

    Chicago Manual of Style (17th edition)

osu1397224105
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This open access ETD is published by The Ohio State University and OhioLINK.