KWAME NKRUMAH UNIVERSITY OF SCIENCE AND TECHNOLOGY, KUMASI. SCHOOL OF GRADUATE STUDIES DEPARTMENT OF CROP AND SOIL SCIENCES RESPONSE OF COWPEA (Vigna unguiculata [L.] Walp) TO NITROGEN AND PHOSPHORUS FERTILIZERS AND RESIDUAL FERTILITY EFFECTS ON GROWTH AND YIELD OF MAIZE (Zea mays L.). BY MOSES AHMED DARAMY SEPTEMBER, 2015 KWAME NKRUMAH UNIVERSITY OF SCIENCE AND TECHNOLOGY, KUMASI. COLLEGE OF AGRICULTURE AND NATURAL RESOURCES FACULTY OF AGRICULTURE DEPARTMENT OF CROP AND SOIL SCIENCES RESPONSE OF COWPEA (Vigna unguiculata [L.] Walp) TO NITROGEN AND PHOSPHORUS FERTILIZERS AND RESIDUAL FERTILITY EFFECTS ON GROWTH AND YIELD OF MAIZE (Zea mays L.). A thesis submitted to the Department of Crop and Soil Sciences, Faculty of Agriculture of the College of Agriculture and Natural Resources, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana in partial fulfillment of the requirement for the award of Master of Philosophy Degree in Agronomy (Crop Physiology) BY MOSES AHMED DARAMY BSc. Hons. Crop Science (Njala University) SEPTEMBER, 2015 DECLARATION I hereby declare that this thesis has not been submitted for a degree to any other University and it is entirely my own work and all references have been duly acknowledged. ……………………………. Date ……………… Moses Ahmed Daramy (20357448) (Student name and ID) CERTIFIED BY: ……………………………. Date………………. Dr. Joseph Sarkodie-Addo (Supervisor) ............................................. Date………………. Dr. Enoch A. Osekre (Head of Department) ii DEDICATION This Thesis is dedicated to my family especially my father, Mr. Alhaji Ansgar Overamy Daramy, my mother, Mrs. Susan Fatmata Daramy Kamara, my brothers and sisters who have always been there for me and kept me in their thoughts and prayers throughout my studies. iii ACKNOWLEDGEMENT To God be the glory for His love, guidance, protection and for granting me the mercy to endure the rigour of this study. I would like to extend my profound gratitude to my supervisor, Dr. Joseph Sarkodie- Addo of the Department of Crop and Soil Sciences, Faculty of Agriculture, KNUST, Kumasi Ghana for his kind advice, understanding, guidance, support and constructive suggestions during this study in order to make this work a success. I am also grateful to Dr. Charles Kwoseh, WAAPP-SL Coordinator and Senior Lecturer, Department of Crop and Soil Sciences, Faculty of Agriculture, KNUST, Kumasi Ghana for his support, patience and fatherly role he played in coordinating our affairs throughout the periods of the studies. I am greatly indebted to my sponsors, the West Africa Agricultural Productivity Programme (WAAPP) for financing my studies and project work. My sincere gratitude also goes to the Sierra Leone Agricultural Research Institute (SLARI) for selecting me as a beneficiary of the scholarship. My sincere thanks also go to the staff of the Plantation Section for their assistance throughout the field work. I also acknowledge with great appreciation, the immense support of my colleagues and friends, Mr. Gibrilla Dumbuya, Miss. Isabelle .O. Traore, Mr. Alex Tamu, Mr. Milton .S. Kanneh, Mr. Aloysius .B. Bangura, Fallah .S. Kassoh and to all who supported me in one way or the other during my studies. iv ABSTRACT Generally, soils in tropical Africa including Ghana are inherently low in essential nutrients particularly nitrogen and phosphorus thereby resulting in low yields of crops. To this end, two field experiments were conducted on the same plot at the Plantation Section of the Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology (KNUST) during the major and minor cropping seasons of 2014 to evaluate cowpea (Vigna unguiculata [L.] Walp) response to nitrogen and phosphorus fertilizers and residual fertility effects on the growth and yield of succeeding maize (Zea mays L.) crop. The design used in the studies was a 4×5 factorial arranged in randomized complete block with three replications. The factors studied were N and P fertilizer application rates. The N rates were 0, 10, 20, 30 and 40 kg N/ha and the P rates were 0, 15, 30 and 45 kg P O /ha. The Asontem cowpea and Abontem maize variety used were obtained 2 5 from the CSIR- Crops Research Institute, with both having a maturity periods of 65 and 75 days respectively. The land was ploughed, harrowed and plots were laid out. Plot size was 4.1 × 1.9 m. Planting for the cowpea was done in June at a spacing of 60 × 20 cm, while that of the maize was done in September at a spacing of 70 × 30 cm. All necessary agronomic practices were carried out. The results indicated that cowpea growth indices were not significantly (P > 0.05) affected by N and P fertilizer application rates. All nodulation parameters were also not significantly (P > 0.05) affected by N and P rates, except for number of nodules at 4 weeks after fertilizer application (WAFA). Grain yield and its component were not significantly (P > 0.05) affected by N and P fertilizer application rates. The results v further indicated that residue quality was not responsive (P > 0.05) to N and P rates. However, application of N had significant (P < 0.05) effects on cowpea total plant N, seed N and crude protein content of seeds. Furthermore, residual fertilization did not significantly (P > 0.05) affect the growth, dry matter and grain yield of the succeeding maize crop. From the studies, it is recommended that, application of N to cowpea fields should highly depend on the N status of that particular field and that further studies should be conducted with higher P rates in other to determine the appropriate rate of P fertilizer that will produce significant effects on growth, grain yields and N contents of whole plant, seeds and residues of cowpea. vi TABLE OF CONTENTS Contents Pages DECLARATION ............................................................................................................... ii DEDICATION ..................................................................................................................iii ACKNOWLEDGEMENT ................................................................................................ iv ABSTRACT ....................................................................................................................... v TABLE OF CONTENTS ................................................................................................. vii LIST OF TABLES .......................................................................................................... xiv LIST OF APPENDIX...................................................................................................... xvi LIST OF ABBREVIATIONS ........................................................................................ xvii CHAPTER ONE ................................................................................................................ 1 1.0 INTRODUCTION ................................................................................................... 1 CHAPTER TWO................................................................................................................ 5 2.0 LITERATURE REVIEW ........................................................................................ 5 2.1 ORIGIN, DOMESTICATION AND DISTRIBUTION OF COWPEA ................... 5 2.2 TAXONOMY AND BOTANY OF COWPEA ....................................................... 7 2.3 MORPHOLOGY AND BIOLOGY OF COWPEA ................................................. 8 2.4 CLIMATIC AND SOIL REQUIREMENTS OF COWPEA ................................. 10 2.5 COWPEA PRODUCTION .................................................................................... 10 vii 2.6 COWPEA PRODUCTION SYSTEMS ................................................................. 11 2.7 COWPEA PRODUCTION CONSTRAINTS ........................................................ 12 2.8 USES OF COWPEA .............................................................................................. 14 2.9 EFFECTS OF NITROGEN AND PHOSPHORUS FERTILIZATION ON COWPEA ..................................................................................................................... 17 2.9.1 Effects of nitrogen (N) on growth and yield of cowpea .................................. 17 2.9.2 Effects of Nitrogen (N) on nodulation and N- fixation of cowpea .................. 19 2.9.3 Effects of phosphorus (P) on the growth and yield of cowpea ........................ 19 2.9.4 Effects of phosphorus (P) on nodulation and nitrogen fixation of cowpea ..... 22 2.10 ORIGIN, DISTRIBUTION, CLASSIFICATION AND BOTANY OF MAIZE . 24 2.11 CLIMATIC AND SOIL REQUIREMENTS OF MAIZE .................................... 25 2.12 IMPORTANCE OF MAIZE ................................................................................ 28 2.13 PRODUCTION STATUS OF MAIZE ................................................................ 28 2.14 CEREAL- LEGUMES CROPPING SYSTEM IN TROPICAL AFRICA .......... 29 2.15 EFFECTS OF RESIDUAL FERTILIZATION .................................................... 32 2.16 QUALITY OF AN ORGANIC CROP RESIDUE ............................................... 33 CHAPTER THREE .......................................................................................................... 36 3.0 MATERIALS AND METHODS .......................................................................... 36 3.1 EXPERIMENTAL SITE ................................................................................... 36 3.2 CLIMATE .............................................................................................................. 36 viii 3.3 PHYSICAL AND CHEMICAL SOIL ANALYSIS .............................................. 37 3.3.1 Organic Carbon ................................................................................................ 37 3.3.2 Soil pH ............................................................................................................. 37 3.3.3 Total Nitrogen .................................................................................................. 38 3.3.4 Available phosphorous..................................................................................... 38 3.3.5 Exchangeable bases (Ca, Mg, K, Na) .............................................................. 38 3.3.6 Particle size analysis ........................................................................................ 39 3.4 EXPERIMENT ONE: TO EVALUATE THE RESPONSE OF COWPEA TO NITROGEN AND PHOSPHORUS FERTILIZER APPLICATION. ......................... 39 3.4.1 Land preparation .............................................................................................. 39 3.4.2 Variety used for the experiment ....................................................................... 39 3.4.3 Experimental design, layout, treatments and planting ..................................... 39 3.4.4 Fertilizer application ........................................................................................ 40 3.4.5 Weeding ........................................................................................................... 40 3.4.6 Pest management ............................................................................................. 41 3.5 DATA COLLECTION ........................................................................................... 41 3.5.1. Plant height ..................................................................................................... 41 3.5.2 Number of leaves ............................................................................................. 41 3.5.3 Leaf Area (LA) ................................................................................................ 42 3.5.4 Stem girth ......................................................................................................... 42 ix