Project – Effect of Organic Fertilizer Application on the Growth and Yield of Maize: A Study of Selected Farmers in Ibadan North Local Government Area, Oyo State

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Agriculture remains one of the most important sectors of the Nigerian economy because it provides food, raw materials, employment and income for a large proportion of the population. Crop production is particularly important to household food security and rural livelihoods. Among the major food crops cultivated in Nigeria, maize (Zea mays L.) occupies an important position because it is consumed directly as food and is also used extensively in livestock feed, poultry production and agro-processing. The International Institute of Tropical Agriculture (IITA) identifies maize as one of Nigeria’s major food crops and notes that increasing population and urbanisation continue to increase demand for maize. However, low productivity, including limitations associated with soil fertility, remains a major constraint to increased production.

Maize requires adequate supplies of essential nutrients throughout its growth cycle. Nitrogen, phosphorus and potassium are particularly important because they contribute to vegetative development, root growth, nutrient uptake, reproductive development and grain formation. Where soils are deficient in these nutrients, maize plants may exhibit poor growth, reduced leaf development, weak stems, delayed maturity and low grain yield. Consequently, maintaining soil fertility is an important component of sustainable maize production.

In many tropical agricultural systems, continuous cultivation can gradually deplete soil nutrients when nutrients removed by harvested crops are not adequately replaced. This problem can be particularly serious where farmers cultivate the same land repeatedly and have limited access to soil amendments. Nutrient depletion may reduce soil productivity over time and contribute to declining crop yields. For maize farmers, therefore, appropriate nutrient-management practices are essential for achieving satisfactory production.

Fertilizers are commonly used to replenish nutrients removed from agricultural soils. Conventional inorganic fertilizers such as urea, NPK and single superphosphate can supply nutrients in relatively readily available forms. However, dependence on inorganic fertilizers can present challenges to smallholder farmers because of cost, availability and the need for appropriate application rates. In addition, fertilizer use without adequate attention to broader soil-management practices may not sufficiently address declining soil organic matter and other aspects of soil quality.

Organic fertilizers provide an alternative or complementary source of plant nutrients. Organic fertilizers are materials derived from plant or animal sources, including poultry manure, cow dung, compost, crop residues and other decomposed organic materials. Apart from supplying nutrients, organic amendments can contribute to improvements in soil organic matter, soil structure, moisture retention and nutrient-holding capacity.

The value of organic fertilizer is particularly important in sustainable agriculture because soil fertility involves more than the immediate supply of nutrients. Healthy soils require adequate organic matter and favourable physical, chemical and biological conditions. Organic materials can contribute to these conditions as they decompose and release nutrients into the soil. Thus, organic fertilization may provide both immediate and longer-term benefits for crop production.

The effectiveness of organic fertilizer, however, depends on several factors, including the source of the organic material, nutrient composition, degree of decomposition, rate of application, method of application, soil characteristics, crop variety and environmental conditions. Different organic materials do not necessarily produce identical results. Poultry manure, cow dung and compost, for example, differ in their nutrient content and decomposition characteristics.

Research conducted in southwestern Nigeria provides strong evidence concerning the potential of organic fertilizers for maize production. Ayoola and Makinde (2009) investigated nitrogen-enriched organic fertilizers at Ibadan and reported that organic fertilizer treatments significantly affected maize growth. Their study found that fortified organic fertilizers produced plants comparable in height with those receiving inorganic fertilizer, while poultry manure enrichment improved soil nitrogen and phosphorus.

The relevance of this evidence to the present study is considerable because the earlier research was conducted in Ibadan, an environment with agricultural and climatic characteristics relevant to the proposed study. It demonstrates that organic nutrient sources can influence maize performance under southwestern Nigerian conditions.

Ayoola and Adebayo (2017) further investigated different sources of organic fertilizer and their effects on maize growth and yield components in southwestern Nigeria. Their experiment involved poultry manure, Oyo organic fertilizer and cow dung, among other treatments. The researchers reported significant effects of fertilizer treatments on growth and yield components, with poultry manure combined with urea producing the highest grain yield among the treatments investigated.

The findings of Ayoola and Adebayo (2017) demonstrate that the source and management of organic fertilizer can influence maize productivity. Their work is particularly valuable to the present study because it was conducted in the Institute of Agricultural Research and Training environment at Moor Plantation, Ibadan, Oyo State, making it geographically relevant to research on maize production within Ibadan and surrounding communities.

Earlier field research by Vanlauwe et al. (2007) also examined the use of organic and inorganic fertilizers for maize and cowpea production in Nigeria. Their study included field trials at Ilora and Ibadan and found that fertilizer applications increased maize and cowpea grain yields and improved nutrient concentrations in maize leaf tissue. The researchers reported substantial agronomic effectiveness of compost and combined organic-based fertilizer relative to mineral fertilizer.

This evidence suggests that organic fertilizer should not necessarily be viewed as a complete substitute for inorganic fertilizer in every production situation. Rather, organic and inorganic nutrient sources may complement one another. Integrated nutrient management can combine the immediate nutrient availability of mineral fertilizers with the soil-conditioning and nutrient-contributing benefits of organic materials.

Ojo et al. (2015) investigated poultry manure and single superphosphate in relation to soil fertility, phosphorus fractions and maize yield in southwestern Nigeria. The study found that poultry manure increased soil pH and organic carbon, while the combination of poultry manure and phosphorus fertilizer produced particularly strong effects on maize grain yield. The researchers concluded that combined application was more effective for several of the soil and crop parameters examined.

The importance of application method has also been demonstrated in recent research. Bello (2024) compared poultry manure and compost under surface and incorporated application methods and found that organic manure application improved soil fertility indicators, nutrient uptake and maize yield. The study reported that incorporated compost performed particularly well and also observed residual effects of manure application on soil nutrient status.

These findings indicate that the effect of organic fertilizer is not determined simply by whether farmers apply manure or compost. The quantity, source and method of application may determine how effectively nutrients become available to maize plants. Consequently, farmers require location-specific evidence concerning the forms of organic fertilizer that can improve maize growth and yield.

Organic fertilizer may influence maize growth through several pathways. As organic materials decompose, they release nutrients that plants can absorb. Nitrogen supports chlorophyll formation and vegetative growth, phosphorus contributes to root development and energy transfer, while potassium contributes to physiological processes, water regulation and plant strength. Adequate nutrient availability can therefore promote plant height, leaf production, stem development and ultimately reproductive performance.

Maize growth is commonly assessed through indicators such as plant height, number of leaves, stem girth and leaf area. Yield, on the other hand, may be assessed using parameters such as number of ears per plant, ear weight, number of grains per ear, grain weight and grain yield per hectare. These indicators provide a basis for evaluating whether a particular fertilizer treatment produces meaningful improvements in crop performance.

Recent research from southwestern Nigeria continues to support the importance of organic fertilizer. Oluwagbemi et al. (2021) evaluated compost, organomineral and mineral fertilizer treatments on maize growth and yield at Iyaganku and Moniya farm sites in Ibadan, Oyo State. Their study specifically examined how different fertilizer types affected maize under local conditions.

Research by Ogundijo et al. (2017) also examined integrated fertilizer management using poultry manure and NPK fertilizer in southwestern Nigeria. Their findings indicated that poultry manure influenced nutrient uptake and maize yield, while combined organic and inorganic fertilizer treatments improved nutrient uptake of nitrogen, phosphorus and potassium. The researchers also reported that poultry manure applied alone at 10 tonnes per hectare produced a grain yield substantially higher than the unfertilized control during the first season.

The growing interest in organic fertilizer is also associated with environmental sustainability. Organic waste from households, livestock production, food processing and agricultural activities can become an environmental burden when improperly managed. Converting suitable organic wastes into compost or manure for agricultural use can create an opportunity to recycle nutrients and reduce waste accumulation.

However, organic fertilizer application also requires appropriate management. Fresh manure may contain materials that are unsuitable for immediate application to crops, while poorly processed organic wastes may introduce pathogens, weed seeds or other contaminants. Proper composting, handling, storage and application are therefore important. Farmers need adequate knowledge to ensure that organic materials are used safely and effectively.

Another consideration is the availability of organic materials. Farmers located close to poultry farms, livestock operations or sources of compost may have relatively easy access to manure, while others may face transportation and labour costs. The economic feasibility of organic fertilizer therefore depends not only on its agronomic effectiveness but also on its accessibility and cost.

Smallholder farmers may also differ in their knowledge of appropriate application rates. Applying too little organic fertilizer may fail to provide sufficient nutrients, whereas excessive application may be uneconomical or potentially cause nutrient losses. Evidence-based recommendations are therefore necessary to guide farmers in the appropriate use of available organic materials.

The physical and chemical characteristics of soils in southwestern Nigeria further reinforce the need for appropriate fertility management. Many cultivated soils can experience nutrient depletion under continuous cropping. Organic amendments can contribute to soil organic matter and improve nutrient retention, thereby supporting more sustainable crop production.

Climate variability also makes soil management increasingly important. Organic matter can contribute to improved water-holding capacity and soil structure, potentially helping crops withstand periods of moisture stress. Research on nutrient-enriched organic fertilizers has shown potential for supporting crop growth across varying seasons and has highlighted their relevance to climate-smart agricultural practices.

The importance of maize production extends beyond individual farmers. Maize contributes to food availability and supports several value chains, including poultry and livestock feed, food processing and other agro-industrial activities. Low maize productivity can therefore affect food prices, farmer income and the availability of raw materials for related industries.

For farmers in Ibadan North Local Government Area, improved maize productivity may contribute to household food security and income generation. However, urban expansion and competition for land around Ibadan have also increased pressure on available agricultural land. Efficient use of available farmland is therefore important, making improved soil fertility management particularly relevant.

The use of organic fertilizer may offer an opportunity to improve productivity while simultaneously contributing to sustainable soil management. Nevertheless, the effectiveness of different organic fertilizer practices should not be assumed to be uniform across locations. Local soil conditions, farmer practices, maize varieties, climate and fertilizer sources can influence outcomes.

Although several studies have examined organic fertilizer and maize production in southwestern Nigeria, there remains a need for studies focusing specifically on farmers and agricultural practices within Ibadan North Local Government Area. Much of the available experimental evidence comes from research stations or neighbouring locations. Farmer-based evidence can provide information about how organic fertilizers are actually used under real production conditions.

Furthermore, farmers may apply organic fertilizers differently in terms of source, quantity, timing and method. Some may use poultry manure, others cow dung or compost, while some may combine organic and inorganic fertilizers. Understanding these practices is important for determining the relationship between organic fertilizer application and maize performance among farmers.

The present study therefore focuses on the effect of organic fertilizer application on the growth and yield of maize among selected farmers in Ibadan North Local Government Area, Oyo State. The study will examine the forms of organic fertilizer used by farmers, their application practices and the observed effects on maize growth and yield.

By generating evidence from the study area, the research is expected to contribute to improved agricultural decision-making. The findings may help farmers understand the potential benefits and appropriate use of organic fertilizers, while agricultural extension officers may use the evidence to develop practical recommendations suitable for local farmers.

The study is also expected to contribute to the broader goal of sustainable agricultural production. Improving soil fertility through appropriate organic amendments can potentially increase maize productivity while supporting soil quality. This is particularly important in an agricultural environment where farmers need productive and sustainable ways of managing available land.

1.2 Statement of the Problem

Maize is an important food and industrial crop in Nigeria, yet maize farmers continue to face challenges associated with low productivity. IITA identifies poor soil fertility as one of the constraints affecting maize production and notes that low grain yields remain an important challenge despite Nigeria’s substantial maize production.

One major factor contributing to low crop productivity is inadequate soil fertility management. Continuous cultivation without adequate nutrient replacement can reduce the availability of essential nutrients required for maize growth and grain formation. Farmers who cultivate nutrient-depleted soils may consequently obtain poor plant growth and low yields.

The conventional response to soil nutrient depletion is often the application of inorganic fertilizer. Although mineral fertilizers can provide essential nutrients, their cost and availability may create difficulties for smallholder farmers. Furthermore, exclusive reliance on mineral fertilizers may not adequately address declining soil organic matter and other aspects of soil quality.

Organic fertilizers provide an alternative source of plant nutrients and may improve the physical and chemical condition of soils. Research in Ibadan and other parts of southwestern Nigeria has demonstrated that poultry manure, compost and other organic amendments can improve maize growth, nutrient uptake and yield.

However, the availability of evidence does not automatically mean that farmers in every locality obtain the same benefits. Organic fertilizers differ in nutrient composition, and their effectiveness depends on application rate, timing, method and the characteristics of the soil. Farmers may therefore obtain different results from apparently similar organic fertilizer practices.

Another problem is inadequate information regarding the actual practices of farmers in Ibadan North Local Government Area. Experimental studies provide useful evidence under controlled conditions, but farmers operate under different circumstances involving labour availability, access to organic materials, financial resources, land size, soil conditions and knowledge of fertilizer management.

There may also be differences in the sources of organic fertilizer used by farmers. Poultry manure, cow dung and compost do not have identical nutrient compositions. If farmers select or apply these materials without adequate knowledge of their characteristics, the expected improvements in maize growth and yield may not be achieved.

Application rate is another concern. Some farmers may apply organic fertilizer at rates that are insufficient to meet maize nutrient requirements, while others may apply large quantities without considering economic returns or nutrient availability. Determining the relationship between application practices and maize performance is therefore important.

The method of application may also affect effectiveness. Bello (2024) found differences between surface and incorporated application of organic manure and reported stronger soil and yield responses with incorporated compost. This suggests that simply possessing organic fertilizer may not be sufficient; farmers need knowledge of appropriate methods of application.

There is also the issue of timing. Organic materials generally release nutrients as they decompose, meaning that the timing of application relative to planting can influence nutrient availability. Poor timing may result in nutrients becoming available after the period of greatest crop demand or may increase nutrient losses.

Although studies have established positive effects of organic fertilizer on maize, some evidence also suggests that integrated nutrient management may produce stronger results than organic fertilizer alone. Ogundijo et al. (2017), for example, found that combined poultry manure and NPK fertilizer improved nutrient uptake, while their research also demonstrated the yield benefits of poultry manure. Thus, farmers require evidence to determine whether organic fertilizer alone is sufficient or whether it can be effectively integrated with other nutrient sources.

The problem is particularly relevant to Ibadan because previous research conducted within the city has demonstrated the potential of organic fertilizers for maize production. Ayoola and Makinde (2009) reported significant effects of enriched organic fertilizers on maize growth at Ibadan. However, experimental results from research institutions cannot automatically be assumed to represent the experiences of farmers operating under ordinary production conditions.

Furthermore, recent research at agricultural sites in Ibadan has continued to examine fertilizer effects on maize, indicating the continuing importance of nutrient management for local crop production. Oluwagbemi et al. (2021) investigated compost, organomineral and mineral fertilizer treatments at Iyaganku and Moniya in Ibadan. This demonstrates the continuing relevance of local evidence on fertilizer use.

There is consequently a need to investigate the situation among selected farmers in Ibadan North Local Government Area. Such a study can help establish what types of organic fertilizers farmers use, how they apply them and whether their application is associated with differences in maize growth and yield.

The problem addressed by this study is therefore the insufficient farmer-level evidence concerning the effect of organic fertilizer application on the growth and yield of maize among selected farmers in Ibadan North Local Government Area, Oyo State.

Without adequate local evidence, farmers may continue to use organic fertilizers without clear knowledge of the most effective sources, rates and application practices. Agricultural extension workers may also lack location-specific information needed to formulate appropriate recommendations.

This study consequently seeks to provide empirical evidence concerning the effect of organic fertilizer application on maize growth and yield among selected farmers in Ibadan North Local Government Area. The findings are expected to contribute to improved fertilizer-management practices, enhanced maize productivity and more sustainable soil fertility management.

1.3 Aim of the Study

The main aim of this study is to examine the effect of organic fertilizer application on the growth and yield of maize among selected farmers in Ibadan North Local Government Area, Oyo State.

1.4 Objectives of the Study

The specific objectives are to:

1. identify the major types of organic fertilizers used by maize farmers in Ibadan North Local Government Area;
2. examine the methods and rates of organic fertilizer application among selected maize farmers;
3. assess the effect of organic fertilizer application on the growth of maize;
4. determine the effect of organic fertilizer application on the yield of maize; and
5. examine the challenges faced by farmers in the use of organic fertilizers for maize production.

1.5 Research Questions

The study will answer the following research questions:

1. What types of organic fertilizers are commonly used by maize farmers in Ibadan North Local Government Area?
2. What methods and rates of organic fertilizer application are used by the selected farmers?
3. What effect does organic fertilizer application have on the growth of maize?
4. What effect does organic fertilizer application have on the yield of maize?
5. What challenges do farmers encounter in the use of organic fertilizers for maize production?

1.6 Research Hypothesis

The following null hypothesis will be tested at the 0.05 level of significance:

H₀: Organic fertilizer application has no significant effect on the growth and yield of maize among selected farmers in Ibadan North Local Government Area, Oyo State.

1.7 Significance of the Study

The study will be significant to maize farmers because it will provide information about the potential contribution of organic fertilizer to maize growth and yield. The findings may help farmers make better decisions concerning the selection, application and management of organic fertilizer.

Agricultural extension officers will benefit from the study because the findings may provide local evidence that can be incorporated into extension programmes. Extension workers can use the information to advise farmers on appropriate organic fertilizer sources, application methods and management practices.

The study will also be useful to agricultural development agencies. Evidence concerning the effectiveness and challenges of organic fertilizer use may help such agencies develop programmes aimed at improving soil fertility and increasing maize productivity.

Government agricultural policymakers may benefit from the findings. The study may provide information useful for policies promoting sustainable soil management, organic waste recycling and improved crop productivity.

The study will also be relevant to environmental sustainability. Appropriate use of organic wastes as agricultural amendments can contribute to nutrient recycling and reduce the volume of agricultural and livestock wastes requiring disposal.

Researchers and students of Agricultural Science, Crop Science, Soil Science and related disciplines may also find the study useful as a reference for future research on organic fertilizer, maize production and sustainable agriculture.

Finally, the study will contribute to existing literature on organic fertilizer application and maize production, particularly within the southwestern Nigerian context and Ibadan North Local Government Area.

1.8 Scope of the Study

The study focuses on the effect of organic fertilizer application on the growth and yield of maize among selected farmers in Ibadan North Local Government Area, Oyo State.

The study will examine major types of organic fertilizers, including poultry manure, cow dung, compost and other locally available organic materials used by the selected farmers. It will also consider application rate, timing and method of application.

The growth of maize will be considered using relevant indicators such as plant height, number of leaves, stem development and general crop performance. Yield will be examined using indicators such as number and size of ears, grain production and estimated yield.

Geographically, the study will be restricted to selected maize farmers within Ibadan North Local Government Area. The findings will therefore be interpreted within the context of the selected farmers and should not automatically be generalised to all maize farmers in Oyo State or Nigeria.

1.9 Operational Definition of Terms

Agriculture: The cultivation of crops and rearing of animals for food, income, raw materials and other human needs.

Organic Fertilizer: Fertilizing materials derived mainly from plant, animal or other naturally occurring organic sources, including compost, poultry manure, cow dung and other decomposed organic materials.

Maize: A cereal crop scientifically known as Zea mays L., cultivated for food, animal feed, industrial raw materials and other purposes.

Maize Growth: The vegetative and developmental performance of maize plants from establishment through maturity, measured using indicators such as plant height, number of leaves and stem development.

Maize Yield: The quantity of maize grain produced by a given area of land, usually expressed as kilograms or tonnes per hectare.

Poultry Manure: Organic waste consisting principally of poultry droppings and associated bedding materials that can be properly processed and used as a soil amendment.

Cow Dung: Organic manure obtained from cattle waste and used as a source of nutrients and organic matter in crop production.

Compost: Decomposed organic material produced through controlled biological decomposition of suitable plant and animal materials.

Soil Fertility: The capacity of soil to provide essential nutrients and suitable physical, chemical and biological conditions necessary for healthy plant growth.

Fertilizer Application: The process of placing or incorporating fertilizer into or onto the soil for the purpose of supplying nutrients to growing crops.

Smallholder Farmer: A farmer operating a relatively small-scale agricultural production enterprise, typically using limited land, labour and financial resources.

Organic Agriculture: An agricultural production approach that places emphasis on ecological processes, nutrient cycling and the responsible use of organic inputs.

1.10 Organisation of the Study

The study will be organised into five chapters. Chapter One presents the introduction, background to the study, statement of the problem, aim and objectives, research questions, hypothesis, significance, scope and operational definitions of terms. Chapter Two will review relevant literature on organic fertilizer, maize production, soil fertility, maize growth and yield, theoretical perspectives and empirical studies. Chapter Three will present the research methodology, including research design, study area, population, sample size, sampling procedure, research instrument, validity and reliability, data collection and methods of data analysis. Chapter Four will present and analyse the data collected and discuss the findings in relation to the research questions and hypothesis. Chapter Five will provide the summary, conclusion, recommendations and suggestions for further studies.

Project – Effect of Organic Fertilizer Application on the Growth and Yield of Maize: A Study of Selected Farmers in Ibadan North Local Government Area, Oyo State