Description
ABSTRACT
This study was conducted to investigate the effects of different irrigation sources (canal, tube-well and sewage) on growth, yield and heavy metal uptake of tomato. Growth attributes (plant height, number of leaves, relative leaf chlorophyll content and leaf area) and yield components (number of fruits and fruit size) of tomato was significantly increased with sewage water application. Lesser growth and yield of the studied vegetables was recorded with tube-well water. Use of sewage water improved total yields and fresh and dry plant biomass production of the vegetable. Significantly higher and lower lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), chromium (Cr) and iron (Fe) contents were recorded in edible parts of the sewage and tube-well water irrigated vegetables, respectively. Edible parts (tomato fruits) of the sewage water irrigated vegetables exhibited heavy metals contents above the maximum permissible limits. Leaf and root samples of the sewage water irrigated tomato also contained significantly greater metals contents as compared to those irrigated with canal and tube-well water. It is concluded that vegetables irrigated with sewage water produced greater yields but these were found contaminated with heavy metals.
TABLE OF CONTENTS
TITLE PAGE
APPROVAL PAGE
DEDICATION
ACKNOWELDGEMENT
ABSTRACT
TABLE OF CONTENT
CHAPTER ONE
- INTRODUCTION
- BACKGROUND OF THE STUDY
- PPROBLEM STATEMENT
- AIM/OBJECTIVE OF THE STUDY
- SCOPE OF THE STUDY
- LIMITATION OF THE STUDY
- PROJECT ORGANISATION
CHAPTER TWO
LITERATURE REVIEW
2.0 LITERATURE REVIEW
2.1 OVERVIEW OF TOMATOES
2.2 WATER: SUPPLY AND SOURCES
2.3 REVIEW OF THE STUDY
CHAPTER THREE
3.0 MATERIALS AND METHODS
3.1 Cultivation of Vegetable
3.2 DATA COLLECTION
3.3 DETERMINATION OF HEAVY METALS PRE-TREATMENT
3.4 CHEMICALS
3.5 ACID DIGESTION AND ANALYSIS
3.6 STATISTICAL ANALYSIS
CHAPTER FOUR
4.1 RESULTS
CHAPTER FIVE
- CONCLUSIONS
- REFERENCES.
CHAPTER ONE
1.0 INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Freshwater is an inimitable natural source with fascinating qualities. Worldwide availability of clean water is deficient as its demand has increased three folds since 1950s mainly in countries of African, Middle Eastern and South Asian regions (Gleick, 2013). There are several contributing factors leading to water shortage in Africa including poor distribution systems of irrigation, salty ground water, rapid population growth and frequent drought conditions. This situation has led to the application of untreated city waste water for irrigating agricultural lands which has now become a common and prevalent practice in Africa especially in Nigeria (Khalil , 2011) and in many other developing countries of the world Nath et al., 2019).
Waste water is a possible source of organic and inorganic elements needed for plant growth ( Khan et al., 2013; Mosleh and Almagrabi, 2013). Farmers exploit waste water for irrigation in farming areas located in the vicinity of cities or around the industrial zones, considering this type of water as valuable and inexpensive source of nutrients and an appropriate alternative of fertilizers ( Murtaza et al., 2010). Waste water holds vital nutrients for plant growth such as N, P and K, and micronutrients including Fe, Mn, Zn and Cu in addition to a substantial quantity of organic matter that contributes to enhance crop productivity (Rai et al., 2011; Ullah et al., 2011; Gosh et al., 2012). The increased growth and yield of corn raised by application of sewage water was ascribed to the presence of macro and micronutrients in waste water (Harati, 2013). Similar results were reported by Segura et al. (2012) suggesting significant increase in the yield of tomato and melon irrigated with waste water grown in greenhouse. Chalkoo et al., (2013) noticed that application of waste water along with phosphorus fertilization significantly increased growth with improved physiological, biochemical and yield attributes of chilli.
Waste water irrigation is generally considered as a main cause of buildup of heavy metals in the soils (Mapanda et al., 2015; Sharma et al., 2017; Ullah et al., 2011; Mosleh and Almagrabi, 2013). Excessive accretion of heavy metals in farming soils irrigated with waste water, not only cause soil contamination, but also contribute to elevate the levels of heavy metal accumulation in plants and thus jeopardize the food value and safety of the crops (Muchuweti et al., 2016). According to WHO (2016), recommended safer levels of various heavy metals for intake of human are Pb (2 mg/kg), Ni (10 mg/kg), Cu (10 mg/kg), Fe (150 mg/kg), Cd (0.02 mg/kg) and Cr (1.3 mg/kg). Intake of heavy metals through contaminated vegetables can exert a substantial health threat to humans, predominantly in levels exceeding the body needs (Banerjee et al., 2011). These metals, being highly toxic and non-biodegradable, damage human health when ingested even at parts per billion (ppb) level. These are gradually released into the body and can cause several diseases (Singh et al., 2010). The harmful impacts of heavy metals include incurable, neurotoxic, mutagenic, carcinogenic and teratogenic consequences (Sharma et al., 2018; Patra et al., 2010). The elevated heavy metals contents have also been reported to negatively influence blood acidity, and cause retardation, kidney damage, different types of cancer and even death among humans. This situation might become shocking for vegetarians as their main component of the food include fresh vegetables.
Food safety is one of the most pressing challenges. Evidence is available to suggests that majority of Pakistani foods are drastically implicated with contaminants like heavy metals; hence pose a dreadful threat to the human health and well-being (Akhtar, 2015). There is an increasing demand for food safety measures, which has stimulated researchers to evaluate food stuffs contaminated with heavy metals, which may cause health risks upon their consumption (D’Mello, 2013). In view of these facts, this study was envisaged to evaluate the growth, yield and accumulation of heavy metals in summer vegetable (tomato) grown in Nigeria.
1.2 AIM OF THE STUDY
The main aim of this work is to investigate the effects of different irrigation sources on growth, yield and heavy metal uptake of tomatoes.
- To study the importance of irrigation to tomatoes
- To study the different types of irrigation system used in Nigeria.
1.3 SCOPE OF THE STUDY
Growth attributes (plant height, number of leaves, relative leaf chlorophyll content and leaf area) and yield components (number of fruits / pods per plant and fruit size) of tomato were significantly increased with sewage water application. Field experiments was conducted in this study to investigate the effects of different irrigation sources on growth, yield and heavy metal uptake of two summer vegetables i.e. tomato.
1.4 LIMITATION OF STUDY
As we all know that no human effort to achieve a set of goals goes without difficulties, certain constraints were encountered in the course of carrying out this project and they are as follows:-
- Difficulty in information collection: I found it too difficult in laying hands of useful information regarding this work and this course me to visit different libraries and internet for solution.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
- Time Constraint: The researcher will simultaneously engage in this study with other academic work. This consequently will cut down on the time devoted for the research work.
1.5 PROJECT ORGANISATION
The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.
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