Land suitability for viticulture : a geographic information system-derived method for a Mediterranean type climate in California

144 Pages·1995·3.4 MB·English

by  Watkins, Russell L

LAND SUITABILITY FOR VITICULTURE:
A GEOGRAPHIC INFORMATION SYSTEM-DERIVED METHOD FOR
A MEDITERRANEAN TYPE CLIMATE IN CALIFORNIA
By
RUSSELL L WATKINS
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1995
ACKNOWLEDGMENTS
Many thanks to the numerous people who have contributed to this study
in one form or another. Special thanks to my Chair, Dr. Cesar Caviedes, for
teaching me the value of a holistic, experiential approach to science, and to my
Co-chair, Dr. Joann Mossa, for her unflagging support and emphasis on the
details necessary for a successful research project. To Dr. Timothy Fik of
course goes my gratitude for his patience with and insight into my statistical
education, and most importantly, his friendship. Thanks to Dr. Scot Smith for
his timely advice and continual support of my doctoral efforts, and to Dr. Harry
Paul for his patience with my applied, non-philosophical approach to a topic we
are both intensely interested in.
Mention must be made of a few other special individuals. Dr. Peter
Waylen, who threw me a lifeline when I was awash in a sea of data, and to my
"External Research Committee", Thomas Olmsted, Richard Browning, and John
Newton, without whose continual encouragement and research support, both
liquid and financial, this study would not have come about. Finally, a wish of
gratitude to parents, for whom no additional words are needed.
TABLE OF CONTENTS
CHAPTERS
ACKNOWLEDGEMENTS
ii
LIST OF TABLES iv
LIST OF FIGURES v
ABSTRACT
vii
INTRODUCTION
1 1
Research Problem 5
Hypothesis 6
Setting of Study 7
2 RELEVANCE OF RESEARCH AND PREVIOUS
LITERATURE 18
Relevance 18
Land Evaluation Literature 20
Implications of GIS and Relevant Literature 23
Viticultural Literature 24
3 METHODOLOGY 27
Description of Technique and Process 27
Selection of Approach 28
Data Collection and Description 29
Data Input 38
Data Manipulation 42
Statistical Methods 46
4 RESULTS 58
Climate Description 58
Vineyard and Sample Area Comparison 61
Statistical Results 85
Interpretation of Results 97
5 CONCLUSIONS 99
Spatial Accuracy and Resolution Limitations 99
Strengths of the Method 107
Opportunities for Future Research 109
APPENDIX 113
LIST OF TABLES
TABLE 3-1 ENVIRONMENTAL FACTORS AND KEY RESULTS
OF PREVIOUS VITICULTURAL LAND
SUITABILITY STUDIES 31
TABLE 3-2 SUMMARY OF SOIL VARIABLES COLLECTED
FROM THE VITICULTURAL LITERATURE 34
TABLE 3-3: VARIABLES USED IN STUDY BY CLASS 35
TABLE 4-1: SUMMARY OF CORRELATION MATRIX RESULTS 87
TABLE 4-2: MAJOR FACTOR NAMES 90
TABLE 4-3: SUMMARY OF STAGE ONE 93
TABLE 4-4: SUMMARY OF STAGE TWO 95
TABLE 4-5: SUMMARY OF STAGE THREE 97
IV
LIST OF FIGURES
FIGURE 1-1: STUDY AREA LOCATION 9
FIGURE 1-2: ZINFANDEL VINEYARD LOCATION 13
FIGURE 1-3: GENERAL GEOLOGY 15
FIGURE 1-4: GENERAL SOILS 17
FIGURE 3-1: DATABASE CONSTRUCTION PROCEDURES 40
FIGURE 3-2: INFORMATION MODEL CONSTRUCTION
PROCEDURES 44
FIGURE 3-3: SUMMARY OF STATISTICAL PROCEDURES 47
FIGURE 4-1: MEAN MONTHLY PRECIPITATION 60
FIGURE 4-2: STORIE LAND CAPABILITY 63
FIGURE 4-3: SOIL DEPTH 64
FIGURE 4-4: SOIL WATER-HOLDING CAPACITY 66
FIGURE 4-5: SOIL RUNOFF 67
FIGURE 4-6: SOIL ROOTING DEPTH 68
FIGURE 4-7: SOIL FERTILITY 70
FIGURE 4-8: SOIL MOISTURE 71
FIGURE 4-9: SOIL ACIDITY 72
LIST OF FIGURES (continued)
FIGURE 4-10: CATION EXCHANGE CAPACITY 73
FIGURE 4-11: SOIL PERMEABILITY 74
FIGURE 4-12: NATURAL SOIL DRAINAGE 76
FIGURE 4-13: SOIL SAND CONTENT 77
FIGURE 4-14: SOIL SILT CONTENT 78
FIGURE 4-15: SOIL CLAY CONTENT 79
FIGURE 4-16: SLOPE ANGLE 81
FIGURE 4-17: SLOPE ASPECT 82
VI
Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
LAND SUITABILITY FOR VITICULTURE:
A GEOGRAPHIC INFORMATION SYSTEM-DERIVED METHOD FOR
A MEDITERRANEAN TYPE CLIMATE IN CALIFORNIA
By
Russell L. Watkins
May 1995
Chairman: Dr. Cesar Caviedes
Major Department: Geography Department
This study has applied geographic information system (GIS) techniques
as the basis for an understanding of the relationship of environmental variables
and viticultural land suitability. Spatial analysis of a viticultural region in a
Mediterranean-type climate in northeastern California, incorporating the
Shenandoah Valley and Fiddletown Approved Viticultural Areas, was
undertaken using the Arc/Info GIS software.
The research problem focusses on the development of measurable
environmental criteria based on the characteristics of existing Zinfandel vineyard
and non-vineyard areas, to evaluate new land areas for viticultural suitability.
Twelve soil and two topographic variables were compared, including Storie
VII
Capability Index, depth, percent content of sand, silt and clay, water-holding
capacity, natural runoff, effective rooting depth, fertility, moisture, acidity, cation
exchange capacity, slope angle and slope aspect.
Factor analysis was initially used to reduce the number of variables
describing the data sets. Similarity analysis using the Mann-Whitney U test
was applied to discriminate the factor descriptions of the physical characteristics
of Zinfandel vineyards from non-vineyard areas. Upon measuring the similarity
of the data sets containing factor coefficients, no statistically significant
difference was found between the medians of the environmental variables.
Similarity analysis of the observations on the complete variable data set
identified differences at the 95% confidence level between Zinfandel vineyard
and non-vineyard areas in the medians of the slope angle, slope aspect, Storie
Index, soil depth, water-holding capacity and cation exchange capacity
variables. Effective rooting depth, natural runoff, and clay content were
significantly different at the 85% confidence level. This level represented a
clear break in the structure of the data sets. Overall, 53% of the variables can
be identified as having characteristics that are significantly dissimilar between
the Zinfandel vineyard and non-vineyard areas.
A reliance on secondary data and the inherent power and flexibility of
geographic information system techniques are the main ingredients for a
viii
location and crop independent suitability reconnaissance. The method
developed here provides the foundation for the successful construction of a
predictive model of viticultural land suitability.
IX
CHAPTER
1
INTRODUCTION
Wine is a wonderful example of a multifaceted geographic phenomenon.
The questions of origin and means of diffusion loom large in any historical
study. In addition, the regionalization ofwine production areas encompasses a
spatial dimension that has both physical and cultural components.
Although the origin of grape (Vitis vinifera) cultivation, or viticulture, is
unclear, most researchers generally agree that the cultivation of vines for wine-
making originated some time before 4000 B.C. and possibly as early as
6000 B.C. The location was in the mountainous region between the Black Sea
and the Caspian Sea, on the borders of the modern states of Turkey, Syria,
Iraq, Iran and the Soviet Union (Unwin, 1991; Nunez and Walker, 1989; de Blij,
1983). The first instances of wine production, or vinification, are subject to
conjecture only, and are thought to have been the result of natural fermentation
resulting from the interaction of wild yeasts with grapes in storage (Unwin, 1991;
de Blij, 1983; Dickenson and Salt, 1982; Stanislawski, 1975).
Numerous factors have historically influenced the geographical pattern of
viticulture and viticultural decision-making, including physical environment, local
cultural, political and economic influences. For example, the early location of
1