CHAPTER ONE

INTRODUCTION

Background to the Study

Foraminifera Market Research (2014) reported that many countries, including Nigeria, produce a wide variety of agricultural products that serve as raw materials for industrial manufacturing and provide food for both humans and animals. This contributes to the growing demand for agricultural commodities, one of which is maize.

Maize (Zea mays L.) belongs to the cereal family and has contributed significantly to human welfare. It ranks as the third most important cereal crop in global food production after wheat and rice (Food and Agricultural Organisation, 2003), accounting for more than 24% of total cereal production (Salami et al., 2007).

Maize (Zea mays L.) is cultivated extensively across many parts of the world, particularly in the humid tropics and sub-Saharan Africa, because of its adaptability and high productivity. It serves as a staple food for humans and provides a major source of calories in animal feed (Okoruwa, 1995). The crop is also valued as feed for various animals, including poultry, cattle, pigs, goats and rabbits (DIPA, 2006). Furthermore, maize serves as an important raw material in the production of several industrial products, such as corn starch, maltodextrins, corn oil, corn syrup, and products used in fermentation and distillation industries.

In recent years, maize has also been utilized in biofuel production (Khaliq et al., 2004). However, maize yield has continued to decline, reaching levels as low as 1 tonne per hectare. This decline has been associated with several factors, including the rapid depletion of soil fertility, inadequate use of soil improvement materials, and the failure to identify high-yielding varieties suitable for specific agro-ecological zones (Kim, 1997; Olakojo, 1998; DIPA, 2006). Other contributing factors include low soil organic matter content and poor crop establishment (Jaliya et al., 2008; Amanullah et al., 2009). In addition, insect pest attacks, diseases, weed infestation, irrigation-related factors, seasonal variations and post-harvest losses also affect maize production (Rosner et al., 2008).

Successful maize establishment can be enhanced by modifying soil structure through appropriate tillage practices. Tillage is performed to create favourable soil conditions for seed germination, seedling emergence and crop growth. Its purposes include improving soil tilth, enhancing water infiltration and retention, reducing weed competition and soil erosion, controlling pest infestation, promoting the biological activities of soil microorganisms, and facilitating the recycling of soil organic matter through residue management (Adamu and Abdulrazaq, 2004; Aluko and Lasisi, 2009; Agbede, 2010). Tillage also loosens the soil surface, incorporates fertilizers and organic residues into the soil, and prepares a suitable seedbed to support germination and plant development (Rasmussen, 1999).

According to the Ministry of Agriculture, Food and Rural Affairs, Ontario (2014), tillage is particularly beneficial for maize cultivation on soils with relatively slow internal drainage. Under such conditions, tillage can promote soil drying and warming, facilitate timely planting, and encourage rapid and uniform emergence of maize seedlings.

Statement of the Problem

Various organic materials, including cattle dung, poultry droppings, pig manure and refuse compost, have been recommended to subsistence farmers in West Africa as soil amendments for improving maize productivity in response to declining soil fertility (Sobulo and Babalola, 1992; Olayinka, 1996; Ismail et al., 1999).

Maize and several other crop species often respond favourably to the application of organic manure compared with chemical fertilizers. Organic manure can help maintain maize yield under continuous cultivation across different soil textures (Maynard, 1991). However, the effective use of manure to meet crop nutrient requirements depends on understanding the quantity of nutrients released through mineralization after application (Eghball et al., 2002).

The application of poultry manure to maize fields is considered an alternative means of supplying nutrients, improving soil fertility and increasing maize productivity, particularly under organic farming systems. This is associated with its capacity to enhance chemical decomposition and make nutrients available for plant uptake (Zorita et al., 2000). Poultry manure is also a natural fertilizer containing substantial amounts of nitrogen and other essential plant nutrients. In addition, it contributes organic matter to cultivated soil, thereby supporting improved maize production (Hussein, 1997).

Repeated applications of manure or poultry litter can increase soil concentrations of nitrogen, phosphorus, potassium, carbon and magnesium (Wood et al., 1996; Ginting et al., 2003). Consequently, these materials can establish a reserve of nutrients that remains available in the soil for several years following application.

Despite the potential benefits of poultry manure and tillage practices, their individual and combined effects on maize growth and the physical and chemical properties of Ultisol require evaluation. Therefore, this study examines the responses of maize and selected soil physical and chemical properties to poultry manure application and different tillage practices in an Ultisol.

Research Objectives

The objectives of this study are to:

1. Assess the effects of poultry manure application on the physical and chemical properties of the soil.

2. Determine the effects of poultry manure on the growth parameters of maize.

3. Examine the effects of tillage practices on maize growth.

4. Evaluate the combined effects of poultry manure application and tillage practices on maize growth.

Research Questions

The following research questions guide the study:

1. What effects does poultry manure application have on the physical and chemical properties of the soil?

2. How does poultry manure application influence the growth parameters of maize?

3. What effects do different tillage practices have on maize growth?

4. How do the combined application of poultry manure and different tillage practices affect maize growth?