Addisu Mergia

Topics: Soil, Earthworm, Humus Pages: 83 (19048 words) Published: April 26, 2015
ABUNDANCE AND DIVERSITY OF TOP SOIL EARTHWORMS
IN RELATION TO CHEMICAL USE IN GOLDEN ROSE
AGROFARM, TEFKI AREA, ETHIOPIA
By

Addisu Mergia
Addis Ababa University
School of graduate Studies
Department of Biology

A thesis submitted to the School of Graduate studies of Addis Ababa University in partial fulfillment of the requirement for the Degree of Master of Science in Biology

July, 2007

Dedication
This work is dedicated to my father who let the ground for my current educational careers, but not alive today to see the finals

Acknowledgements
I would first like to appreciate my advisors Dr. Seyoum Mengistou and Dr. Fiseha Itanna for their proper follow up, constructive and stimulating advice and friendly treatment at every stage during the preparation of this paper. I am grateful to Mr. Sunil Chavdhari, Production Manager at Golden Rose Agrofarm, for allowing me to freely conduct my research in the farm and for providing me with all the information relevant to this project. I am also grateful for the cooperation and assistance from the farm workers at Golden Rose Agro farm, particularly Ato Teferi Kebede, Ato Tesfahun Yusuf, Ato Gebrehiwot Mebratu, Ato Getu Bekele, Ato Asmelash Tilahun, Ato Sileshi Borena and Ato Shimelis Werk during the study period. I would also like to express my gratitude to the School of Graduate Studies of Addis Ababa University for providing financial support, and the Department of Biology in particular for facilitating my work. My deepest gratitude also goes to my friends who constantly supported and encouraged me with several constructive ideas at different stages of this thesis work, particularly Mr. Cosmas, M. for his help in constructing map of the study area, and Ayalew Berhanu and Admassu Tassew for their constructive comments at different stages of this work. Lastly, I would like to appreciate my lovely family for their endless encouragement and support during the entire period.

CONTENTS
Acknowledgements .................................................................................. ii List of tables............................................................................................ v List of figures .......................................................................................... vi Abstract .................................................................................................. vii 1. Introduction ........................................................................................ 1 1.1. Background...................................................................................... 1 1.2. Problem Statement .......................................................................... 4 1.3. Objectives....................................................................................... 5 2. Literature Review................................................................................. 6 2.1. The structure of earthworm communities ....................................... 6 2.1.1. Major ecological groups ............................................................... 6 2.1.2. Species Diversity ........................................................................ 7 2.1.3. Species Associations................................................................... 8 2.2. Effects of agricultural practices and chemicals on abundance and distribution of earthworms............................................................ 9 2.2.1. Cultivation, cropping, chemicals and fertilizers ........................... 9 2.3. Modes of toxicity of chemicals to earthworms.................................. 15 2. 3. 1. Malformations, effects on nervous and physiological functions, reproduction, growth and activity ............................. 16 2.4. Uptake and bio-accumulation of chemicals into earthworms........... 18 2.5. The influence of environmental factors on abundance and distribution of earthworms...
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