The Effect of Organic Manure on Soil Fertility and Crop Performance in Southwestern Nigeria

CHAPTER ONE

1.1 Background to the Study

Agriculture remains one of the most important sectors of Nigeria’s economy. It provides food, employment, and raw materials for industries. In recent years, the need for sustainable soil management has gained attention due to declining soil fertility and environmental concerns. Continuous cultivation, poor land management, and overreliance on chemical fertilizers have contributed to soil degradation and reduced crop yields.

Organic manure plays a vital role in maintaining soil health and improving crop performance. It consists of decomposed plant and animal materials that enrich the soil with nutrients and enhance its structure. According to Ayoola and Makinde (2019), organic manure increases the soil’s water-holding capacity, promotes microbial activity, and improves long-term fertility.

In Southwestern Nigeria, many farmers depend on chemical fertilizers because they provide quick results. However, excessive use has led to soil acidification, nutrient imbalance, and environmental pollution. Organic manure, on the other hand, offers a more sustainable and eco-friendly alternative. It releases nutrients gradually, supporting continuous crop growth and soil regeneration.

Moreover, the availability of organic waste materials such as animal dung, crop residues, and compost provides an affordable option for smallholder farmers. Studies have shown that combining organic and inorganic fertilizers can further boost yield and ensure soil sustainability (Adebayo et al., 2020).

Given the importance of soil fertility to agricultural productivity, understanding the effect of organic manure on crop performance is essential. This study, therefore, examines how the use of organic manure influences soil properties and crop yield in Southwestern Nigeria.

1.2 Statement of the Problem

Declining soil fertility has become a serious threat to sustainable agriculture in Nigeria. Farmers often experience low yields despite increased fertilizer use. The high cost of inorganic fertilizers also limits their accessibility, especially among small-scale farmers. As a result, many have turned to organic manure as an alternative soil amendment.

However, there is limited information on how different types and quantities of organic manure affect soil properties and crop growth under local conditions. In some cases, poor composting or incorrect application reduces effectiveness. Without adequate knowledge, farmers may not achieve the full benefits of organic fertilization.

This study addresses these gaps by evaluating the effects of organic manure on soil fertility and crop performance. It aims to determine how organic materials can improve productivity and promote sustainable farming practices in Southwestern Nigeria.

1.3 Objectives of the Study

The main objective of this study is to determine the effect of organic manure on soil fertility and crop performance in Southwestern Nigeria. The specific objectives are to:

1. Assess the types of organic manure commonly used by farmers in the study area.

2. Evaluate the impact of organic manure on key soil fertility indicators such as nitrogen, phosphorus, and potassium.

3. Determine the effect of organic manure on crop growth and yield performance.

4. Recommend best practices for the effective use of organic manure to improve soil and crop productivity.

1.4 Research Questions

1. What types of organic manure are commonly used by farmers in Southwestern Nigeria?

2. How does organic manure affect soil fertility indicators?

3. What is the impact of organic manure on crop growth and yield?

4. What best practices can enhance the effectiveness of organic manure use?

1.5 Research Hypotheses

• H₀₁: Organic manure has no significant effect on soil fertility in Southwestern Nigeria.

• H₀₂: Organic manure application has no significant effect on crop performance.

1.6 Significance of the Study

This study is important because it provides scientific evidence on the effectiveness of organic manure in improving soil fertility and crop performance. The findings will help farmers make informed decisions about soil management and fertilizer use. Policymakers and agricultural agencies can also use the results to promote sustainable soil fertility programs.

Furthermore, the study contributes to environmental protection by encouraging the recycling of organic waste into useful agricultural inputs. For researchers, it adds to existing knowledge on organic soil amendments and sustainable agriculture in tropical regions.

1.7 Scope and Limitations of the Study

The study focuses on selected farming communities in Southwestern Nigeria, where crops such as maize, cassava, and vegetables are widely grown. It examines different types of organic manure, including animal dung, compost, and crop residues. Time constraints, limited access to laboratory analysis, and farmers’ record-keeping habits may affect data accuracy. Nonetheless, the study provides reliable insights into the benefits of organic manure.

1.8 Definition of Key Terms

• Organic Manure: Naturally decomposed plant and animal materials that improve soil fertility and structure.

• Soil Fertility: The ability of soil to supply essential nutrients required for plant growth.

• Crop Performance: The growth rate, yield, and quality of crops under specific soil and management conditions.

• Sustainable Agriculture: Farming practices that meet current food needs without compromising future productivity.