| dc.description.abstract | Despite the potentially large gains from intensification and agricultural productivity growth in Sub-Saharan Africa (SSA), yields of staple crops, such as maize are far below attainable yields. Depletion of soil fertility associated with low and inappropriate use of nutrients play a crucial role in this. Yet, fertilizer use is low in SSA, which partly relates to information constraints. Relaxing such constraints via agricultural extension interventions is expected to produce positive outcomes but do not always result in the intended effects, which may be connected with the highly heterogeneous smallholder farming systems. Yet, traditional extension systems in SSA countries, including Nigeria, provide general fertilizer use recommendations, which do not account for the substantial variation in production conditions. A potential intervention in this regard is site-specific nutrient management (SSNM) paradigm. In light of the rapid digital transformation, digital decision support tools (DSTs) can be leveraged to allow provision of SSNM extension advice. There are research gaps in the theoretical and empirical literature on design, adoption and impact of DST-enabled site-specific extension services, and in the broader literature related to fertilizer use in maize. This PhD thesis focuses on a nutrient management DST for maize ‘Nutrient Expert’ in northern Nigeria, and addresses some of the gaps.
In chapter 2, I analyze farmers’ preferences for intensification of maize production supported by DST-enabled SSNM recommendations in the maize belt of Nigeria. I use data from a choice experiment (CE) among farmers, and estimate different econometric models to control for attribute non-attendance and account for preference as well as scale heterogeneity. The findings show that overall, farmers have strong preferences to switch from general to DST-enabled SSNM recommendations, which lend credence to the inclusion of digital tools in agricultural extension. Also the findings show two latent classes or preference groups of farmers, early and late adopters of intensified maize production, and the heterogeneous preferences can be related to the farmers’ resource endowment, sensitivity to risk and access to services and institutions. The findings imply that improving the design of DSTs to enable provision of information on the riskiness of expected investment returns and flexibility in switching between low- and high-risk recommendations will help farmers to make better informed farm decisions.
In chapter 3, I analyze preferences of extension agents for the design of a nutrient management DST for extension, and their willingness to use such tool. I use data from a CE among extension agents, and estimate different models to capture preference heterogeneity and account for attribute non-attendance. The findings show that the extension agents in general have a high willingness to use DSTs for SSNM extension advice, which supports the emerging policy interest in design of such DSTs for maize. They prefer a DST with a more user-friendly interface that requires less time to generate an output but have substantial heterogeneous preferences for other design features. The findings also show two preference groups of extension agents, the more committed agents – who prioritize the effectiveness-related features of DSTs, and the more pragmatic agents – who care more about practical features of DSTs. The differences in observed characteristics between the two groups are very small, which suggests that unobservable characteristics likely play a role in explaining preference heterogeneity. The findings imply that accommodating preference differences may facilitate the adoption of DSTs by extension agents and thus enhance the scope for such tools to impact the production decisions of farmers.
In chapter 4, I analyze the impact of farmers’ access to SSNM recommendations for maize enabled by a DST on fertilizer use rates, fertilizer management practices, maize yield and revenue. I implement a randomized controlled trial with two treatment groups, T1 without and T2 with additional information on variability of expected returns and a control group. I use three-period panel data to estimate the impact. The findings show that SSNM recommendations bring about improvements in fertilizer management practices, yield and gross revenue after one-year treatment but not fertilizer use for T1. This suggests that optimal management practices can improve yield and revenue by reducing technical inefficiencies. The findings also show that yield and revenue gains are quite similar for the two treatment groups despite considerable increase in fertilizer by T2 over T1. This suggests that the increase in fertilizer does not result in substantial revenue gains, which may be connected to low yield responses to higher fertilizer levels. The findings also show that SSNM recommendations, combined with additional information on the distribution of expected returns, appears to induce more fertilizer use after one year and foster continued fertilizer investment after two years. In addition, the findings show that there are only gradual increases in investment, maize yield and especially net revenue after two years.
Overall, this dissertation shows that there is high adoption potential of nutrient management DSTs for maize by extension agents, and of extension advice from such DSTs by farmers, which aligns with the widespread interest and investments in site-specific and digital tools for agricultural applications in developing countries. Yet, the findings show economically small but significant effects of DST-enabled SSNM recommendations on intensification of maize production. This underscores the need for more research with longer periods and with complementary interventions to allow better understanding of the impact of DST-enabled site-specific recommendations in the long run while accounting for other shortcomings. |
| cg.contributor.acknowledgements | First and foremost, I am eternally grateful to the Almighty God for the successful completion
of my PhD program. I want to return all the glory, honor and adoration to Him for His
faithfulness to me and my family throughout the course of my program. At first sight, it may
seem as if one can independently go through the challenging moments of a PhD journey.
However, it is worth noting that I would not have been able to complete the journey without
receiving the support and encouragement of a lot of wonderful people in different ways,
directly or indirectly.
At this point, I have a lot of people to appreciate. First of all, I wish to express my
heartfelt and profound gratitude to my supervisor, Prof. Miet Maertens. Miet, I want to thank
you for giving me the opportunity to undertake a PhD program under your scholarly
guidance. Thank you for your patience, enthusiasm, encouragement and strong commitment
to my progress from my enrollment into the pre-doc to the doctoral program. Indeed, you
have been very supportive all the way, and I am extremely grateful for all the critical
comments, valuable suggestions and feedback that you gave me at every stage of my
research, which has immensely enriched the respective chapters of this dissertation. Truly, I
feel very happy and fulfilled working with you over the period of my program because of the
opportunity of learning a lot from you – both in terms of research- and non-research related
issues. I am also grateful to you for supporting my participation in academic conferences, for
providing me a pleasant working environment at the division, and for making my stay in
Leuven worthwhile.
I would like to deeply appreciate my co-supervisors: Prof. Roel Merckx, Prof. Jan
Diels and Dr. Jordan Chamberlin. Roel and Jan, I thank you for your scholarly inputs and
critical comments, which help to improve the quality of my work, and for keeping track of
my progress from the pre-doc up to the defense stage. Jordan, I would like to thank you for
been a part of my PhD journey. I am thankful to you for meticulously reviewing my research
proposal and the draft papers, and for all the discussions we had, especially about the
conceptual framework in chapter four of this dissertation. You have greatly contributed to
this dissertation, especially by your unflinching support in the design and conduct of my field
activities as part of the Taking Maize Agronomy to Scale in Africa (TAMASA) project
implementation in Nigeria. I am very grateful to you for the experience I had in managing the
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three rounds of farm-household panel surveys and learning about the whole process in the use
of Computer-assisted Personal Interviews (CAPI) for farm-household surveys. I look forward
to more collaboration with you. I will like to appreciate Prof. Liesbet Vranken for giving me
useful comments and feedbacks on the choice experiments in this thesis and for accepting to
be part of my jury. I will also like to deeply appreciate all other jury members: the chairman,
Prof. Josse De Baerdemaeker, Prof. Steven Bouillon, Prof. Peter Goos and Prof. Erwin Bulte
for contributing immensely to this dissertation through their constructive comments and
suggestions.
Despite my quest for a top-notch PhD, I would not have been able to achieve it in KU
Leuven without a scholarship. To this end, I wish to acknowledge the Bill and Melinda Gates
Foundation [grant number OPP1113374] for the financial support for my PhD through the
International Maize and Wheat Improvement Centre (CIMMYT) led project ‘TAMASA’. My
gratitude goes to the TAMASA project leader, Dr. Peter Craufurd for providing visionary
leadership for the project implementation in general and in particular, for giving me valuable
comments, suggestions and support for my PhD research activities. Despite your busy
schedule, you were able to review a draft paper for me. I am extremely grateful to Dr.
Bernard Vanlauwe, who was very supportive, particularly during the discussions about my
research proposal and my research stay at the International Institute of Tropical Agriculture
(IITA), Kano station with Miet. Thank you for been a source of inspiration to me and many
other young African researchers affiliated to IITA and other CGIAR centres. I am extremely
grateful to the station representative of IITA, Kano station, Dr. Alpha Kamara for
contributing immensely to my PhD program in different ways. In the first place, I would not
have embarked on this PhD if you had not motivated me to do so. Thank you for advising and
encouraging me to look beyond my comfort zone in Zaria and seek for a better PhD
experience elsewhere. I am also grateful to you for supporting my research stay at IITA,
Kano station and for the many discussions we had about conducting quality empirical
research in IITA. At first, I was very reluctant to stay in Kano but you made me feel
comfortable with the idea of staying in Kano, and supported me with a conducive working
environment. Apart from that, you were very instrumental to the successful planning and
implementation of my field activities. My sincere gratitude goes to Prof. Jibrin M. Jibrin, the
director Centre for Dryland Agriculture (CDA), Bayero University, Kano, Nigeria for
contributing to my field activities. Thank you for your strong commitment to the conduct of
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the three rounds of panel survey by ensuring that CDA was actively involved in the whole
exercise.
Many thanks go to TAMASA team members at IITA, Kano station. I would like to
thank the TAMASA-Nigeria country coordinator, Prof. Ibrahim Baba for his contributions,
particularly in facilitating the logistics for my field activities. Thank you for leading all the
discussions we had with other project partners about my field work, and ensuring that I got
their continuous support throughout the field activities. I am wholeheartedly grateful to Dr.
Julius Adewope, who supported me with the spatial sampling framework of farm-households,
and for supervising the production of the maps used in this dissertation. My deepest
appreciation goes to Mr. Kamal, who supported me in various ways, including the
preliminary visits to the survey communities, the training of enumerators for the farmhousehold surveys, the training of extension agents for the pilot of Nutrient Expert tool, and
the supervision of my field activities. Also, I am grateful to Mrs. Helen Jerome, who was
primarily responsible for the production of the maps used in this dissertation, and to Mrs.
Princess Ifeanyi, who gave me the necessary administrative support during my field work and
my stay in Kano. I will like to thank all other IITA, Kano station staff, especially Mr. Rabo,
Dr. Lucky, Mr. Reuben, Mr. Tofa, Mr. Olumide and the IITA postgraduate research fellows
for their support and friendship during my stay in Kano.
My profound gratitude goes to all the people and institutions that participated in the
planning and conduct of the data collection, and the pilot of Nutrient Expert tool as part of the
randomized controlled trial implemented in this dissertation. I deeply appreciate all the welltrained enumerators who diligently participated in the three-period farm-household panel
survey and the agricultural extension agents survey. Notable among them are Abu, Atiku,
Nura, Salisu, Francis, Kalu, Fidelis, Jamilu, Wilson, Mohammed, Josiah, Richard, Ahmadu,
Joel, Desmond, Grace and others. Also, I am grateful to Baba, Ismail, Hailru, Mbavai,
Luqman and AY, who supervised the survey teams in the data collection, and made sure the
data collection plan was adhered to. My sincere gratitude goes to the agricultural extension
agents who contributed to the implementation of the randomized controlled trial by piloting
the use of Nutrient Expert tool in the treatment villages, and the field support staff who
supervised the exercise. Special thanks go to the following institutions, Kaduna State
Agricultural Development Agency (KADA), Katsina State Agricultural and Rural
Development Authority (KTARDA), Kano State Agricultural and Rural Development
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Authority (KNARDA) and Sasakawa-Global 2000 for their support. I am extremely grateful
to the 792 maize farmers and the 320 extension agents who accepted to be respondents for the
farm-household and extension agents surveys respectively, and for dedicating their time for
the surveys. Also, I will like to recognize the efforts of the community leaders in the survey
communities and my contact persons in the extension organizations for their roles in
facilitating the field activities.
My PhD experience at the Division of Bioeconomics was truly amazing. Thanks to
the many wonderful and helpful colleagues: Erik, Tessa, Frederik, Pieter, Monica, Jana,
Bernd, Michiel, Fikadu, Natalia, Teopista, Goedele, Isabelle, Moses, Joseph, Anna, Eewoud,
Floris, Kaat, Genaye, Tafesse, Tijstke, Nuria, Cindybell, Karin, Diana, Kewan, Marie,
Charlotte, Ashenafi, Iris, Tilahun, Lucia and Kato. Thank you for the scholarly comments and
feedbacks during seminar presentations, the insightful methodological discussions, the
memorable social events and the moments we shared at the lunch room and the Geo-garden.
Also, I would like to appreciate my case administrator at the international office, Heidi, Hilde
at the ICT unit and Karlien for their support.
I had an overwhelming support from my friends and family during the course of my
PhD program. I am most grateful and indebted to my beloved wife, Grace Oyinbo for her
love, prayers, encouragement and invaluable support. It was really difficult but you had the
strength to combine family, work and your PhD study during my stay in Belgium. Thank you
for taking care of our daughters, Eliora and Aviya throughout this period. I truly owe my PhD
success to you. My profound gratitude goes to my parents, Mr. and Mrs. Peter Oyinbo and
parents-in-law, Prof. and Mrs. Peter Rekwot for their prayers and moral support. Thank you
for your parental love and care to me, and especially to my lovely wife and kids during my
stay in Belgium. Also, I am grateful to my siblings and in-laws for their support throughout
my study period.
Back in Nigeria, I would like to appreciate my colleagues at the Department of
Agricultural Economics and the Department of Agricultural Extension and Rural
Development, Ahmadu Bello University, Zaria, Nigeria for their support. Also, I am grateful
to the management of the University for giving me study leave to undertake this PhD project. |
