ABSTRACT
The development of a Mini low-cost lysimeter was carried out and the lysimeter evaluated by using it to estimate the consumptive water use of tomatoes (lycopersicon esculentum) in sandy loam soil of Umudike in South Eastern Nigeria.The Mini low cost lysimeter with diameter of 30 cm and depth of 60 cm was constructed fromlocally sourced materials.A cylindrical shape was chosen to achieve the least resistance to flow of water The tomatoes (lycopersicon esculentum) were established on the lysimeter and irrigated daily and the daily data generated from the lysimeter were used to calculate the crop evapotranspiration (ETc Lysimeter) for the months of November and December 2017, and January and February 2018. Climatic data obtained for the same period were used to determine the crop evapotranspiration (ETc) using Blaney – Criddle and Thornthwaite methods. The evapotranspiration (ETc) estimates by Blaney – Criddle and Thornthwaite methods were compared with the estimates from the lysimeter. The total crop evapotranspiration for Lysimeter for the four months was 1039.2 mm, while that of Blaney – Criddle and Thornthwaite methods were 871.4 mm, and 276.3 mm, respectively. The margin between the results of the empirical methods and the lysimeter could be as a result of environmental factors prevalent within the experimental site. The result of the statistical analysis carried out on the results obtained from the mean consumptive use show that there is significant different between the lysimeter method and the other two methods for 5% level of significance at the growth period of four months.
TABLE OF CONTENTS
Details page
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of content vi
List of Tables ix
List of Figures xi
Abstract xii
CHAPTER 1: INTRODUCTION
1.1 Background of the Study 1
1.2 Statement of Problems 5
1.3 Objectives 6
1.4 Justification 6
1.5 Scope of the Work 7
CHAPTER 2: LITERATURE REVIEW
2.1 Definition of Terms 8
2.1.1 Tomato 8
2.1.2 Evapotranspiration 8
2.1.3 Potential evapotranspiration 9
2.1.4 The actual evapotranspiration 10
2.1.5 Consumptive use 10
2.1.6 Field capacity 11
2.1.7 Effective root zone 11
2.1.8 Lysimeter 12
2.2 Factors Affecting Consumptive Use 13
2.2.1 Soil factors 13
2.2.2 Weather Factors 13
2.2.2.1 Precipitation 13
2.2.2.2 Temperature 13
2.2.2.3 Humidity 14
2.2.2.4 Wind 14
2.2.3 Crop factors 15
2.2.3.1 Stage of growth of the plant 15
2.2.3.2 Type of foliage 15
2.2.3.3 Rooting pattern 15
2.3 Different Stages of Tomatoes Growth. 16
2.3.1 Preplant stages 17
2.3.2 Planting to prebloom 17
2.3.3 Bloom to early set 17
2.3.4 Late fruits set to first colour/20% colour 18
2.3.5 Red fruit/ pre harvest 18
2.3.6 Postharvest 19
2.4 Factors Affecting the Performance of Tomatoes 19
2.4.1 Genetic factor 19
2.4.2 Environmental factor 20
2.4.3 Temperature 20
2.4.4 Moisture supply 20
2.4.5 Radiant energy 20
2.4.6 Composition of the atmosphere 20
2.4.7 Soil reaction 21
2.4.8 Biotic factors 21
2.4.9 Supply of mineral nutrient 21
2.4.10 Absence of growth restricting substance 21
2.5 Different Models for Determining Consumptive Water Use 21
2.5.1 Blaney –Criddle method 22
2.5.2 Penman methods 24
2.5.3 Modified Penman method 25
2.5.4 Penman- Monteith formula 25
2.5.5 Doorunbus and Priut method 26
2.5.6 Thornthwaite method 27
2.6 Soil Water Balance Method 28
2.7 The Lysimeter 29
2.7. 1 Types of lysimeter 30
2.7.2 The Lysimeter method of determining consumptive use of crops 31
CHAPTER 3: MATERIALS AND METHODS
3.1 Site Description 32
3.2 Materials 32
3.3 Data Collection 33
3.4 Design Consideration 33
3.5 Soil Analysis 33
3.5.1 Moisture content determination 34
3.5.2 Bulk density determination 34
3.5.3. Particle density determination 35
3.5.4 Porosity measurement 35
3.5.5 Soil textural classification 36
3.6 Moisture Measurements 36
3.6.1 Field capacity 36
3.6.2 Water holding capacity 37
3.7 Determination of Consumptive Use using Empirical Models 37
3.7.1 Blaney-Criddle method 37
3.7.2 Thornthwaite method 37
3.7.3 Lysimeter design and construction 38
3.7.4 Evaluation of the lysimeter 39
3.8 Statistical Analysis 40
CHAPTER 4: RESULTS AND DICUSSIONS
4.1 Results 45
4.2 Discussion 60
CHAPTER 5: CONCLUSION AND RECOMMENDATION
5.1 Conclusion 64
5.2 Recommendations 65
REFERENCES
APPENDIX
Picture of the lysimeter set with the planted tomatoes 71
Picture of the student taking readings in November 2017 72
Picture of the lysimeter set in December 2017 73
Picture of the student taking readings in January 201874 74
Picture of the lysimeter set in February, 2018 75
Picture of the student taking readings in February, 2018 76
LIST OF TABLES
The results of the design parameter, calculations and specifications 44
The Results of the soil physical properties at the experimental site at different depths. 45
The results of the textural classification of the soil at different depths 46
The results of the consumptive use values estimated by using blany-criddle method for the growing season. 47
Results of the consumptive use values estimated by using thornthwaite method for the growing season. 47
The results of the consumptive use of tomato for the month of November 2017 using the mini lysimeter. 50
The results of the consumptive use of tomato for the month of December 2017 using the mini lysimeter. 51
The results of the consumptive use of tomato for the month
of January 2018, using the mini lysimeter. 52
The results of the consumptive use of tomato for the month of February 2018, using the mini lysimeter. 53
The summary of the consumptive use of tomatoes using the selected model and lysimeter for the growing season. 54
The results of the regression analysis of consumptive use of tomatoes using the selected model and lysimeter for the growing season. 55
LIST OF FIGURES
The Side view of the lysimeter 4
Pictorial view of the lysimeter 41
Isometric drawing of the lysimeter 42
plan of the base of the lysimeter 43
The chart of the results of Eto for the three methods for the four months. 61
Consumptive use values estimated by blaney-criddle, thorenthwaite and lysimeter methods 62
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Food security is a major concern all over the globe including West Africa, and Nigeria in particular. In order to meet up with the high demand for food that occurs due to increasing population, irrigation agriculture becomes very necessary. For plants to grow well, water is required since it provides the medium and the environment within which most cellular functions take place (Condon et al., 2002).When planning for irrigation, water requirement for crop developmental stages, how it is applied and the responses of crop to weather variables are crucial across different agro- ecology. Thus, crop varietal development may not have been completed when appropriate information of water requirement of a crop do not exist, making production of such crops under irrigation subjected to inadequate planning (Oke et al., 2017).The major purpose of irrigation agriculture is to increase crop production. If irrigated agriculture is to accomplish its main objective of increased crop production through efficient and adequate management of irrigation water, efforts to minimize unnecessary waste of water through proper scheduling that is, knowing when to irrigate and the right amount of water to apply, is necessary (Olorunaiye, 2009). Generally, crop production is adversely affected when water requirement of crop is not satisfactorily met. In order to forestall this situation, it is paramount to ascertain the cost of additional water demand by crops and the corresponding increase in yield associated with it. Therefore, for proper evaluation of an irrigation system, knowledge of the relationship between water demand of crops and the subsequent yield is very vital. The water requirements of the crop vary from crop to crop considering other factors that may affect it.
Also, the way a crop responds to moisture stress in terms of growth and yield varies with crop species, growth stages and the degree of stress (Dooronbos and Kasaam, 1979).When a crop is exposed to drought for a given period of time, thestress intensity will differ depending largely on the evaporative demand and the crop actual evapotranspiration at such a growth stage (Igbadun, 1997). For this reason, theintensity of stress imposed on the crop when moisture is withheld for a few days undera high evaporative demand may be higher thereby creating an adverse effect on the crop performance with regard to yield than a long period of withholding moistureunder a low evaporative demand.
The consumptive water use knowledge is important in the case of a large irrigation project. Basic consumptive use data are used in estimating the irrigation water requirement of existing or proposed projects and for crop production on individual farm (Agele etal., 2011).
The knowledge of consumptive water use is necessary when planning farm irrigation systems and to improve irrigation practices. Data derived from irrigation and consumptive water-requirement are used more widely in planning water distribution.
In order to determine crops water use, water loss due to evaporation and water loss due to transpiration are usually combined into one term evapotranspiration (ET), because separation of these two losses in cropped fields is quite difficult. In crop farming, evapotranspiration is the combination of water losses due to water loss from soil and from plant's surface. The term consumptive use designates the losses due to evapotranspiration (ET) and that utilized by plants for metabolic activities (which is regarded as being insignificant) (Allen et al., 2006). Accurate measurement of water requirements of crops are essential so as to factor the time variations on irrigation needs, improving the allocation for water resources, and to evaluate the effect of land use and changes in the water balance management (Ortega - Farias et al., 2009). A number of methods exist to either measure or estimate evapotranspiration and are usually variants of mass balances, energy balances or meteorological approaches. (Medellín-Azuara and Richard, 2013). Measurement of evapotranspiration can be carried out by direct and indirect methods and involves panevaporation, lysimeters, eddy correlations, Bowen ratio, LIDAR and satellite information. The results obtained from the calculations generally depend on the weather data quality control and quality assurance procedures.
Most of the estimations are empirical, pan evapotranspiration which is one of the simplest method, and also considered easy to use is weather dependent. (Abtew and Melesse, 2012). Crop consumptive use can be determined by direct or estimated measures of climatic elements, by employing empirical models. The direct method entails using several types of lysimeters, being the most accurate method, and also considered standard - tool for the measurement of evapotranspiration (Bernardo et al., 2006). The accuracy of lysimeter data depends on the ability to achieve identical conditions between the lysimeter and the surrounding field.
Howell, et al., (1991) showed that accuracy of lysimeter was a factor of the surface area in direct proportion and also the scale accuracy in Inverse proportion to lysimeter mass. If lysimeters are designed to meet specific requirements for the research performed and are operated properly, then they can be utilized as precision tool to measure actual evapotranspiration (Howell et al., 1991). Lysimeters are the most practical research tool when measuring daily evapotranspiration and it is a very good way of carrying out studies of crop coefficient, when properly used (Yrisarry and Naveso, 2000).
Tomatoes (lycopersicon esculentum) are popular and widely grown crops. It is of the lycopersicon family usually cultivated because of its fruits which are edible (Jones, 1990). Tomatoes contain high levels of vitamins A, B, C, E and nicotinic acid (Murano, 2003) thus, a vital means of supplying vitamins to the body.
On the average, the fruit contains 8% protein, 34% minerals mainly (K+, Ca+ and P), 48% total soluble sugars, 9% citric acid and 0.5% vitamins (Murano, 2003). In Nigeria, tomatoes are considered to be most consumed only behind onions and pepper (Fawusi, 1978). They can be eaten fresh or in multiple of processed forms. Recently, tomatoes consumption has been linked to prevention of several diseases, because of its high antioxidants contents, namely carotenes (lycopene and carotene), ascorbic acid, and phenolic compounds (Willcox et al., 2003, Toor, et al., 2006 and Pariago et al., 2009).
Tomato has high potential for water for its optimal vegetative and productive development (Jones, 1990). Tomatoes cover a larger space in terms of acreage more than other vegetables world over., and it is the most commonly grown food producing plants in backyards garden today (FAO, 2017). It is important as a dietary staple vegetable and cash earning plant in Nigeria. It has very high returns on investment in addition to its economic importance; the tomato is an ideal research material for physiological, cellular, biochemical and molecular genetics (Pan,et al., 2013). It is easy to cultivate, its life span is short and is amenable to varied horticultural manipulations, including grafting, or cutting (Hillel, 1990). The high income potential as well as its demand for greater yield all year round prompt for the cultivation of tomatoes regardless of the season. Tomato production before the rainy season is likely to give better and higher yield and thus more income though may be accompanied with adverse temperature and limiting moisture conditions which in turns affect yield of crops (Agele et al.,2004). Although tomatoes cultivation is beset with many problems, e.g. diseases, nematodes, insects and high flower drop which result in low yield and poor quality fruits, these problems can be checked easily by proper management and care. Irrigation technology though considered to be very essential owing to the seasonal rainfall events and occasional occurrence of drought is not widely practiced.
Modern irrigation practice must target at making optimal use of available water and other natural and human resources while considering all essential inputs namely energy, machinery, and fertilizer and pest control measures. In many regions, irrigation accounts for a large proportion all water used more than water use for other purposes (Van Schilfgaarde, 1994). Low cost lysimeter have been advocated either because of high degree of success or high expense involved in using empirical models and 5 remoteness of research areas (Schneider et al., 1996). In this study, low cost mini lysimeters were developed and used to evaluate water use of tomatoes and the results used to relate to some of the existing empirical models.
1.2 STATEMENT OF PROBLEMS.
Determining the amount of water required by crop during various stages of its life span has always posed a great challenge to farmers and water managers. Water requirements by crops vary significantly, and the knowledge of its variations at various stages of growth is critical in reducing the risk of crop failure due to over irrigation or under irrigation.
Quantification of crop water use will proffer more detailed information on the use of available water, creates a more robust and improved irrigation planning, as these can best be achieved by improved low cost lysimeter
1.3 OBJECTIVES OF THE STUDY
The general objective of this work is to develop and evaluate a mini lysimeter for determination of consumptive water use of tomato (Lycopersicon esculentum).
The specific objectives are to:
i Determine some physical properties of the soil at the experimental site
ii Estimate the consumptive use of tomatoes with the developed lysimeter.
iii Compare the results obtained from the lysimeter with the results of selected ET models
1.4 JUSTIFICATION
The recognition and quantification of crop water demands are made possible and practicable by using crop water production functions (crop consumptives use). It is imperative to develop and create a more robust data based information on the water requirement of tomatoes both for rain fed and irrigated agriculture. This study furnishes the local farmers the required data for proper planning for all season production. It will also go a long way in providing the basic information required for deficit irrigation in the face of various soil moisture condition and scarcity of water.
To embark on all season production of tomatoes, one must be able to harness and optimize the available water. Therefore, for proper evaluation of an irrigation system, knowledge of the relationship between water demand of crops and the subsequent yield is very vital.
1.5 SCOPE OF THE WORK
This thesis was carried out in Michael Okpara University of Agriculture, Umudike and covers the development and evaluation of a low cost mini weighing lysimeter constructed from locally available materials for determination of consumptive use of tomato (lycopersicon esculentum) and comparing the result obtained with the results of selected models. The selected models were considered on the basis of the climatic data collected from the National Root Crop Research Institute meteorological station. This work extended to three to four months that covers the life span of tomatoes from emergence to maturity stage.
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