ABSTRACT

Soil enzymes play essential roles in catalyzing reactions necessary for nutrient cycling in the biosphere. The purpose of this study is to estimate soil microbial enzymes activities of collected soil samples using fluorimetric assays. The general concept of the fluorescence enzyme assay is that synthetic Carbon, Nitrogen or Phosphorus rich substrates bound with a fluorescent dye are cleaved from their substrates, which allows them to Florence. Potential Carbon, Nitrogen and Phosphorus enzyme acquisition activities assayed at 0-5cm soil depths did not differ by experimental treatment. Calculating and plotting the sum of all Carbon, Nitrogen and Phosphorus cycling enzyme activities was a useful approach to observe broader patterns regarding their potential cycle. Enzymes activities for total Carbon, Nitrogen and Phosphorus cycling trended lower in the plot exposed to Elevated Heating Condition and CO2  (EHC) compared to the plots exposed to Ambient Climatic Conditions (ACC) at the 5-15cm soil depths. This trend was on significant for total N and P cycling activities (p< 0.046). Potential enzyme C: P and N : P ratios were higher in the plots exposed to Elevated Heating Condition and CO2 (EHC) compared to the plots exposed to Ambient Climatic Condition (ACC) at 5-15cm soil depths (p= 0.05). This observation suggests that there is a relatively higher P mineralization enzyme activity at lower soil depth (5-15cm). For the estimation of soil enzymes activities, Fluorescence-based assays are a useful tool that is widely used to examine potential Enzyme activities among treatment plots.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgement iv

Table of contents v

List of tables vi

List of figures vii

Abstract viii

CHAPTER ONE

1.0 Introduction 1

1.1 Objective of the Study 3

CHAPTER TWO

2.0 Literature Review 4

2.1 Soil Enzymes 4

2.2 Microorganism as Indicators of Soil Health 5

2.3 Types of Soil Enzymes 6

2.4 Origin and State of Soil Enzymes 9

2.5 Importance of Enzymes to Soil Management 9

2.6 Soil Enzyme Activities; A Component of Soil Biodiversity 11

2.7 Environmental Factors Affecting the Distribution of Soil Enzymes 12

2.8 Sources of Soil Enzymes Activities 15

2.9 Methodological Consideration for Estimating/Measuring Enzyme 

Activities in Soils 16

CHAPTER THREE

3.0 Materials and Methods 20

3.1 Materials/Equipment 20

3.2 Enzyme Assay Set-up 20

3.3 Incubation of Assay Plates 22

3.4 Florescent Measurements on a Microplate Fluorometer 23

3.5 Data Analysis 23

CHAPTER FOUR

4.0 Results 26

CHAPTER FIVE

5.0 Discussion, Conclusion and Recommendation 37

5.1 Discussion 37

5.2 Conclusion 38

5.3 Recommendation 39

REFERENCES 40