AN EVALUATION OF SOIL SAMPLING METHODS IN SUPPORT OF PRECISION 
                                 AGRICULTURE IN NORTHEASTERN NORTH CAROLINA 
                                                               
                      
                      
                      
                                                             by 
                                                               
                                                               
                                                               
                                                               
                                                     Joshua Britton Harrell 
                                                               
                                                               
                                                                                                                   
                                                               
                                                               
                                                               
                                                   A Thesis Presented to the 
                                       FACULTY OF THE USC GRADUATE SCHOOL 
                                        UNIVERSITY OF SOUTHERN CALIFORNIA 
                                                  In Partial Fulfillment of the 
                                                 Requirements for the Degree 
                                                   MASTER OF SCIENCE 
                              (GEOGRAPHIC INFORMATION SCIENCE AND TECHNOLOGY) 
                                                               
                                                               
                                                               
                                                               
                                                          May 2014 
                                                               
                                                               
                                                               
                                                               
                                                               
                                                               
                         Copyright 2014                                         Joshua Britton Harrell 
                      ACKNOWLEDGEMENTS 
           
           
          Thank you to my thesis guidance committee chair, Dr. John Wilson, for his guidance and 
          patience through this thesis process.  Thank you also to my committee, Drs.  Karen Kemp 
          and Dr. Su Jin Lee, for their assistance as well.  Finally, to my family and friends, thank 
          you for your support.
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                       TABLE OF CONTENTS 
                             
          Acknowledgements ............................................................................................................. ii 
          List of Figures ......................................................................................................................v 
          List of Tables .................................................................................................................... vii 
          List of Abbreviations ....................................................................................................... viii 
          Abstract .............................................................................................................................. ix 
          Chapter 1:  Introduction .......................................................................................................1 
          Chapter 2:  Related Work ..................................................................................................10 
           2.1 Random Composite Sampling vs. Point Sampling ..................................................11 
           2.2 Grid Soil Sampling Methods ....................................................................................11 
            2.2.1 Point Methods ....................................................................................................12 
            2.2.2 Random Composite Cell Sampling Method ......................................................15 
           2.3 Management Zone Sampling Methods ....................................................................15 
           2.4 Grid/Management Zone Hybrid Soil Sampling Method ..........................................18 
           2.5 Traditional Soil Sampling Methods .........................................................................19 
           2.6 Precision Soil Sampling Guidelines .........................................................................20 
          Chapter 3:  Methods and Data Sources ..............................................................................22 
           3.1 Climate .....................................................................................................................23 
           3.2 Soil Characteristics ...................................................................................................24 
           3.3 Agricultural Practices ...............................................................................................25 
           3.4 Research Location ....................................................................................................25 
           3.5 Sampling Scheme Creation ......................................................................................25 
            3.5.1 Traditional Sampling Scheme ...........................................................................26 
            3.5.2 Grid Sampling Schemes ....................................................................................27 
            3.5.3 Management Zone Sampling Schemes..............................................................27 
            3.5.4 Hybrid Sampling Schemes ................................................................................29 
                                              iii 
           
           3.6 Physical Sample Collection ......................................................................................30 
           3.7 Method Used to Compare Sampling Procedures .....................................................34 
          Chapter 4:  Results and Discussion ....................................................................................36 
           4.1 Measurements...........................................................................................................36 
           4.2 Interpolation Results ................................................................................................46 
           4.3 Real World Application ...........................................................................................54 
          Chapter 5:  Conclusions .....................................................................................................56 
           5.1 Final Thoughts..........................................................................................................56 
           5.2 Considerations for Future Research .........................................................................57 
                                              iv