CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Amaranth is one of the major leafy vegetables cultivated in tropical regions. It has a relatively short growing period of about five to six weeks, making it possible for farmers in both rural and urban areas to harvest two or more crops from the same farmland within a year. The vegetable is also valued for its nutritional content, particularly its minerals and vitamins (Akinmutimi & Okoroji, 2024). These characteristics make amaranth a suitable crop for farmers with limited farmland who require quick returns from their agricultural activities. However, its short production cycle also means that the crop requires an adequate supply of nutrients within a limited period. Nutrient deficiencies that occur during this period may be difficult to correct before harvesting begins.

Since the leaves and tender stems are the main parts harvested and sold, nitrogen plays an important role in amaranth production because it supports the development of these plant parts. Auwalu (1988) examined the effects of four nitrogen application rates of 0, 45, 90 and 180 kg N/ha on vegetable amaranth at Samaru, Zaria. The study found that nitrogen application significantly improved plant height, leaf area, shoot dry weight and the length of harvested branches compared with the control treatment. Applying nitrogen at 180 kg N/ha increased marketable yield by 19.5% and also improved the protein content of the edible portion of the crop. More recent research has shown that the appropriate nitrogen rate may depend on the harvesting method and other production practices. Birhanu et al. (2024), in a study conducted in Ethiopia, examined different nitrogen application rates alongside harvesting frequencies. They recorded the highest leaf yield of 30.33 tonnes per hectare at a nitrogen rate of 103.5 kg N/ha with a harvesting interval of two weeks. This finding suggests that farmers who harvest their vegetables frequently may require a different nitrogen management approach from those who harvest less frequently.

Research conducted in Nigeria has also examined the use of organic materials and combinations of organic and mineral fertilisers as sources of nutrients for amaranth. Adekiya et al. (2019) applied poultry manure at rates ranging from zero to 40 tonnes per hectare to green amaranth during the 2016 and 2017 growing seasons. Their findings showed that poultry manure improved soil chemical properties, the mineral content of the leaves, plant growth and marketable yield compared with the control. The highest quality results were obtained at 20 tonnes per hectare, which the researchers considered a suitable balance between crop performance and production costs. In Umuahia, south-eastern Nigeria, Akinmutimi and Okoroji (2024) investigated fertiliser application on a strongly acidic and continuously cultivated Ultisol with a low total nitrogen content of 0.10%. Their findings showed that NPK fertiliser applied alone at 200 kg/ha produced only a small increase in fresh weight compared with the control. Poultry manure applied at 5 tonnes per hectare produced a much greater improvement, while the highest yield was obtained when 5 tonnes per hectare of poultry manure was combined with 100 kg/ha of NPK fertiliser. The researchers also noted that information on the nutrient requirements of amaranth remains limited in resource-constrained farming environments, particularly regarding the combined use of organic and inorganic fertilisers.

The cost of nitrogen fertilisers has also become an important concern for farmers. In 2025, farmers interviewed by the News Agency of Nigeria reported that the price of a bag of urea had increased from between ₦35,000 and ₦37,000 to approximately ₦47,000–₦50,000. They explained that the increasing cost of fertiliser was forcing some farmers to reduce or abandon the cultivation of certain crops (AllAfrica, 2025). For amaranth farmers, who often cultivate relatively small plots and depend on frequent sales for income, the increasing cost of nitrogen fertiliser raises an important production concern. Farmers must consider how to maintain satisfactory leaf production while reducing fertiliser expenses. One possible approach is to identify suitable application rates or use less expensive organic nutrient sources to supplement mineral fertilisers.

Nsukka Local Government Area is located within the derived savanna vegetation zone of south-eastern Nigeria, where low soil fertility is recognised as an important factor affecting crop production (Onwubiko, 2026). The University of Nigeria, Nsukka, has also contributed to agricultural research, particularly in crop and soil management. However, findings from research experiments mainly explain how crops respond to specific fertiliser rates under controlled or selected experimental conditions. They do not necessarily establish the fertiliser practices followed by amaranth farmers in Nsukka. There is limited information on the nitrogen sources used by these farmers, the quantities applied, the number of applications made during a growing season and the factors influencing their decisions. Information is also lacking on the plant growth and yield outcomes that farmers report under their existing fertiliser practices and the challenges that prevent them from using nitrogen fertilisers as they would prefer.

This study therefore adopts a structured questionnaire to examine nitrogen fertiliser use among amaranth farmers in Nsukka Local Government Area and its relationship with the growth and yield they report. Rather than identifying a single recommended nitrogen application rate, which would require controlled field experiments, the study focuses on documenting existing farming practices, the outcomes farmers associate with those practices and the challenges affecting nitrogen fertiliser use.

1.2 Statement of the Problem

Amaranth farmers in Nsukka depend on nitrogen fertilisers, particularly urea, to support plant growth and maintain satisfactory production. Previous research has established that nitrogen contributes significantly to leaf development and marketable yield in amaranth (Auwalu, 1988; Birhanu et al., 2024). However, the increasing cost of urea has made it more difficult for farmers to obtain the quantities they require (AllAfrica, 2025). In addition, existing experimental studies provide nitrogen application rates obtained under different locations, soil conditions, crop varieties and harvesting practices. For example, the nitrogen rate of approximately 103.5 kg N/ha reported in Ethiopia by Birhanu et al. (2024) and the 180 kg N/ha examined at Samaru by Auwalu (1988) may not be directly suitable for the farming conditions and production practices in Nsukka.

The available literature also provides limited information about the actual nitrogen management practices of vegetable farmers in south-eastern Nigeria. Akinmutimi and Okoroji (2024) observed that information on the nutrient requirements of amaranth remains limited, particularly in relation to the use of organic and inorganic fertilisers. However, there is insufficient information on the nitrogen sources, application rates and timing adopted by amaranth farmers in Nsukka. There is also limited evidence on the growth and yield outcomes they report under different application rates and the reasons influencing their fertiliser choices. Some farmers may apply inadequate quantities of nitrogen and experience reduced leaf production, while others may spend more than necessary on fertilisers. Some may also combine urea, compound fertilisers and organic manure without having sufficient information about the effectiveness of their practices.

These challenges affect farmers, agricultural extension workers and researchers. Farmers may lack reliable information for comparing their fertiliser practices with those of other producers. Extension workers may find it difficult to identify where farmers need guidance on reducing fertiliser costs while maintaining crop productivity. Researchers planning future nitrogen experiments in the area may also lack information about the fertiliser sources and application rates that are commonly used by farmers. At a time when fertiliser prices are increasing, these information gaps may affect production decisions and farm income.

The problem this study seeks to address is therefore the lack of adequate survey information on the nitrogen sources and application rates used by amaranth farmers in Nsukka Local Government Area, the growth and yield outcomes they report under different application rates, and the constraints affecting their use of nitrogen fertilisers.

1.3 Objectives of the Study

The general objective of this study is to examine the relationship between nitrogen fertiliser use and the growth and yield of amaranth as reported by farmers in Nsukka Local Government Area.

The specific objectives are to:

a. Describe the socio-economic and farm characteristics of amaranth farmers in the study area.

b. Identify the nitrogen sources used by farmers, including urea, compound fertilisers, manure and other sources, as well as the application rates and timing.

c. Examine the growth and yield outcomes reported by farmers under different nitrogen application rates.

d. Identify the major constraints affecting farmers' use of nitrogen fertilisers.

1.4 Research Questions

The study will be guided by the following research questions:

1. What are the socio-economic characteristics of amaranth farmers in Nsukka Local Government Area, and what are the sizes and management conditions of their farms?

2. What sources of nitrogen do the farmers use, and in what quantities and at what periods do they apply them?

3. What growth and yield outcomes do farmers report under different nitrogen application rates?

4. What factors prevent or limit farmers from using nitrogen fertilisers as desired?

1.5 Research Hypotheses

The following null hypotheses will be tested at the 5% level of significance:

H01: There is no significant relationship between the rate of nitrogen fertiliser applied and the yield reported by amaranth farmers.

H02: There is no significant difference in the yield reported by farmers who apply nitrogen fertiliser and those who do not.

H03: There is no significant relationship between farmers' socio-economic characteristics, including age, sex, educational level, farm size and farming experience, and the rate of nitrogen fertiliser they apply.

1.6 Significance of the Study

Amaranth Farmers: The study will provide information on the relationship between nitrogen fertiliser application and the yields reported by other amaranth farmers. It will also identify common challenges affecting fertiliser use, particularly the high cost of urea. This information may help farmers assess their production practices and make more informed decisions about nutrient management.

Extension Workers in Enugu State: The findings will provide information on the nitrogen sources and application rates currently used by amaranth farmers. This may help extension workers identify areas where farmers require guidance on efficient fertiliser use and the possible adoption of more affordable organic nutrient sources.

Researchers and Students: The study will provide farmer-level information from Nsukka Local Government Area that can be considered alongside findings from agricultural research stations. It may also serve as a useful reference for future studies and assist researchers in selecting relevant fertiliser treatments for subsequent field experiments.

Policy Makers: The findings will provide information on the difficulties vegetable farmers experience when obtaining and applying nitrogen fertilisers. This may assist policy makers in developing agricultural input support programmes and other interventions aimed at improving horticultural production.

1.7 Scope and Delimitation of the Study

The study focuses on amaranth farmers in Nsukka Local Government Area of Enugu State who cultivated the crop during the most recent growing season. It adopts a cross-sectional survey design and uses a structured questionnaire to obtain information from the respondents.

The research concentrates on nitrogen fertiliser use, including nitrogen supplied through urea, compound fertilisers and manure. It examines the sources used, quantities applied, timing of application, and the growth and yield outcomes reported by farmers.

The study does not cover phosphorus and potassium management as separate research variables, comparisons of amaranth varieties, pest management practices, or the processing and marketing of amaranth.

1.8 Limitations of the Study

The study may encounter the following limitations:

1. Difficulty in measuring harvested yield: Vegetable farmers do not always weigh their harvests using standard measuring equipment. Consequently, some respondents may report their yields in local units such as bundles and baskets. Converting these measurements into standard units using sample measurements may introduce some errors.

2. Inaccurate estimates of nitrogen application: Farmers may apply nitrogen through different fertiliser sources and in several split applications. Estimating the actual quantity of nitrogen applied from the number of bags, cups, basins or other local measurements may therefore be difficult.

3. Repeated harvesting: Amaranth is harvested several times within a relatively short production period. This may make it difficult for farmers to provide one accurate figure representing their total yield for the season.

4. Influence of other production factors: The study is based on survey information and can establish relationships between fertiliser use and reported crop performance, but it cannot prove that nitrogen fertiliser alone caused the observed differences. Other factors, including soil fertility, crop variety, irrigation and general farm management, may also influence growth and yield.

5. Limited time and financial resources: The time and funds available for the research may restrict the number of farmers who can be interviewed and included in the study.

1.9 Definition of Terms

Nitrogen Fertiliser: Any fertiliser applied mainly to supply nitrogen to crops, including urea and other nitrogen-containing fertilisers. The rate of application refers to the quantity of fertiliser, or the amount of nitrogen contained in it, applied per unit area of farmland.

Growth: The development of the amaranth plant as reported by farmers, including plant height, leaf size and number of leaves.

Yield: The quantity of marketable amaranth leaves and tender stems harvested from a given area of farmland.

Amaranth: Leafy vegetable species belonging to the genus Amaranthus that are cultivated by farmers in the study area.

Split Application: The practice of dividing the total quantity of fertiliser required into two or more portions and applying them at different stages of crop growth.

REFERENCES

Adekiya, A. O., Aboyeji, C. M., Dunsin, O., Asamu, F., Owolabi, A. O., Aremu, C. O., Oyetunji, D. A., Oloye, A. D., & Owolabi, I. O. (2019). Poultry manure addition affects production, plant nutritional status and heavy metals accumulation in green amaranth (Amaranthus hybridus). International Journal of Agriculture and Biology, 993–1000.

Akinmutimi, A. L., & Okoroji, M. C. (2024). Effects of organic and inorganic fertilizers on soil chemical properties and the yield of Amaranthus species in a continuously cropped Ultisol. International Journal of Agriculture and Environmental Research, 10(1), 64–74. https://doi.org/10.51193/IJAER.2024.10105

AllAfrica. (2025, July 22). Nigeria: High fertiliser cost – Farmers dump rice, maize cultivation. https://allafrica.com/stories/202507220646.html

Auwalu, B. M. (1988). The effects of nitrogen and plant population on the growth and yield of vegetable amaranth (Amaranthus cruentus L.) [Master's thesis, Ahmadu Bello University, Zaria]. Kubanni Repository. https://kubanni.abu.edu.ng/handle/123456789/4908

Birhanu, T., et al. (2024). Leaf and seed yield response of vegetable amaranths to nitrogen fertilizers applications and harvesting frequency at Jimma, South West, Ethiopia. Discover Food.

Onwubiko, G. N. (2026). Comparative assessment of the morphological traits of local maize (Zea mays L.) varieties upon exposure to varying rates of poultry manure. Current Research in Agricultural Sciences, 13(1), 104–113. https://doi.org/10.18488/cras.v13i1.4944