ABSTRACT
In a study at KNUST weather station,
the crop co-efficient values at initial, development, mid-season, and late
season stages of ABONTEM MAIZE (hybrid variety) were determined as 0.42, 0.98,
1.05, and 0.32, respectively. These locally determined values of ABONTEM hybrid
maize compared favourably with those recommended by FAO. The corresponding FAO
values are 0.4, 0.80, 1.15, and 0.70. The FAO values are average values and
recommended for a wide range of locations, but those determined by this study
are location specific. Another reason may be the use of specific variety of
hybrid maize in this experiment. However, locally determined values are
preferred to standard values (FAO values) in estimating location specific crop
evapotranspiration. The crop water productivity for the ABONTEM maize was found
to be 3.42 kgm-3 as compared to some reported values of 1.1-2.7 kgm-3.
Contents
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TABLE OF CONTENTS
CHAPTER. 8
INTRODUCTION.. 8
1.1 INTRODUCTION.. 8
1.2 JUSTIFICATION OF STUDY. 9
1.3 OBJECTIVE OF STUDY. 10
1.3.1 MAIN OBJECTIVE. 10
1.3.1.1 SPECIFIC OBJECTIVES. 10
CHAPTER 2. 11
LITERATUR E REVIEW... 11
2.1 INTRODUCTION.. 11
2.2 CONCEPT OF CROP COEFFICIENT. 12
2.3 EVAPOTRANSPIRATION CONCEPT. 13
2.4 REFERENCE EVAPOTRANSPIRATION (ETo). 14
2.5 METHODS OF DETERMINING EVAPOTRANSPIRATION.. 15
2.5.1 PENMAN-MONTEITH EQUATION.. 15
2.5.2 BLANEY-CRIDDLE. 17
3.5.3 HARGREAVES EQUATION.. 18
2.5.4 FIELD PLOT METHOD OR WATER BALANCE METHOD.. 18
2.5.5 CLASS A PAN METHOD.. 19
2.5.6 IVANOV EQUATION.. 20
2.5.7 THORNTHWAITE'S FORMULA:20
2.5.8 LYSIMETER. 21
2.6 CROP WATER PRODUCTIVITY. 22
CHAPTER 3. 24
MATERIALS AND METHOD.. 24
3.1 LOCATION OF EXPERIMENT. 24
3.2 MATERIALS. 24
3.2.1 MAIZE VARIETY. 24
3.2.2 MICRO-LYSIMETER. 24
3.3 METHODS. 25
3.3.1 DATA GATHERING.. 26
CHAPTER 4. 27
RESULTS AND DISCUSSION.. 27
4.1 RESULTS. 27
4.1.1 CLIMATIC DATA.. 27
4.1.2 CROP COEFFICIENT. 27
4.1.3 CONSUMPTIVE WATER USE AND REFERENCE
EVAPOTRANSPIRATION.. 29
4.1.4 CROP WATER PRODUCTIVITY. 31
4.2 DISCUSSION.. 31
CHAPTER 5. 32
CONCLUSION AND RECOMMENDATION.. 32
5.1 CONCLUSION.. 32
5.2 RECOMMENDATION.. 32
REFERENCES. 33
