Effect of Organic Manure and Inorganic Fertilizer on the Physicochemical Properties of Sandy Loam Soil

CHAPTER ONE

1.0 Background of the Study

Soil fertility depends on the balance of nutrients, organic matter, and physical structure that support healthy plant growth. In Nigeria, soil degradation and nutrient depletion have become major challenges to sustainable crop production. Many farmlands are now characterized by low fertility and poor structure, especially those dominated by sandy loam soils (Akinrinde & Obigbesan, 2000). These soils often have low organic matter content, poor nutrient-holding capacity, and low water retention ability.

Farmers commonly use fertilizers to restore soil fertility and increase yields. Inorganic fertilizers supply nutrients quickly but may not improve soil structure or microbial activity. On the other hand, organic manures, such as poultry droppings, compost, or cow dung, release nutrients slowly while enriching the soil with organic carbon and beneficial microorganisms (Dauda et al., 2008). When used together, organic and inorganic fertilizers can complement each other, improving both the chemical and physical properties of the soil.

Sandy loam soils are light and easy to cultivate, but they lose nutrients quickly through leaching. Without proper management, crops grown on such soils often show nutrient deficiencies. To sustain productivity, farmers must understand how different soil amendments affect soil properties over time. Combining organic and inorganic inputs can help achieve a balance between immediate nutrient availability and long-term soil health.

Previous studies have shown that the application of organic manure improves soil structure, increases water-holding capacity, and enhances microbial activity (Adekiya & Agbede, 2009). Similarly, inorganic fertilizers boost nutrient supply and promote rapid plant growth. However, excessive or unbalanced fertilizer use can lead to soil acidification and environmental pollution. Therefore, studying their combined effect is necessary for sustainable soil fertility management.

This study focuses on evaluating how organic manure and inorganic fertilizer influence the physicochemical properties of sandy loam soil. The findings will help identify the best soil management practices for improving productivity and maintaining soil health.

1.1 Statement of the Problem

The fertility of sandy loam soils declines rapidly due to their low nutrient retention and organic matter content. Farmers often rely heavily on chemical fertilizers to improve yields. While this practice provides quick results, it does not address long-term soil degradation. Over time, soils become compacted and less productive.

Organic manures improve soil structure but release nutrients slowly, which may not meet immediate crop needs. The challenge is to find a balanced approach that maintains soil fertility while supporting sustainable production. Understanding how these soil amendments affect physicochemical properties will provide practical solutions for managing sandy loam soils effectively.

1.2 Aim and Objectives of the Study

Aim:
To determine the effect of organic manure and inorganic fertilizer on the physicochemical properties of sandy loam soil.

Objectives:

1. To apply organic manure, inorganic fertilizer, and their combination to sandy loam soil samples.

2. To analyze changes in key soil properties such as pH, organic carbon, nitrogen, and phosphorus.

3. To compare the individual and combined effects of organic and inorganic inputs.

4. To recommend appropriate soil amendment practices for sustainable soil fertility management.

1.3 Significance of the Study

This study is significant because it promotes efficient soil management strategies for improving the productivity of sandy loam soils. The findings will guide farmers in selecting the right combination of organic and inorganic fertilizers to enhance soil fertility.

Moreover, the study contributes to sustainable agriculture by encouraging the use of environmentally friendly soil amendments. Researchers, extension agents, and policymakers can also use the results to design soil fertility programs that improve crop yields and preserve soil health for future use.

1.4 Scope of the Study

The study focuses on evaluating the impact of organic manure and inorganic fertilizer on the physicochemical properties of sandy loam soil. It covers laboratory and field analyses of selected soil parameters, including pH, organic matter, total nitrogen, available phosphorus, and exchangeable cations. The study does not include crop yield assessment or microbial analysis.

1.5 Definition of Terms

Organic Manure: Natural materials derived from plants or animals that supply nutrients and improve soil structure.
Inorganic Fertilizer: Chemically manufactured substances that provide essential nutrients to plants in available forms.
Physicochemical Properties: The physical and chemical characteristics of soil, such as pH, texture, and nutrient composition.
Sandy Loam Soil: A soil type containing a mixture of sand, silt, and clay, known for good drainage but low nutrient retention.
Soil Fertility: The capacity of soil to support healthy plant growth through adequate nutrient supply.