Agricultural Science 2019 Jamb Examination

Vitamin deficiency diseases manifest through symptoms such as loss of appetite, scurvy (from lack of vitamin C), and rickets (from deficiency of vitamin D). Improved fertility is not a symptom of deficiency but rather an indicator of good nutrition and health. Hence, it is the exception among the listed options.

Fish processing yields several by-products including fish meal, fish oil, and fish silage. These are valuable in animal feed and industrial uses. Leather, however, is derived from animal hides and not from fish. Therefore, leather is not a by-product of fish.

Crops that require low annual rainfall below 750mm are best suited for semi-arid regions. The Sahel savanna, characterised by sparse vegetation and low rainfall, provides the appropriate environment for such crops. The rain forest and Guinea savanna receive higher rainfall amounts, while the Sudan savanna receives moderate levels.

Micronutrients are nutrients required in very small quantities for plant growth, such as iron, manganese, and boron. Calcium, however, is needed in larger amounts and is classified as a macronutrient. Therefore, calcium does not fall into the category of micro-nutrients.

Soil formation is influenced by natural factors such as climate, vegetation, and topography. These determine the rate of weathering, organic matter accumulation, and soil structure. Farming systems, however, are human activities that affect soil management rather than the natural process of soil formation.

Crop rotation helps maintain soil fertility by alternating crops with different nutrient requirements, breaking pest cycles, and improving soil structure. In contrast, flooding, overgrazing, and bush burning have harmful impacts such as soil erosion, nutrient loss, and land degradation. Hence, crop rotation is the practice that does not harm soil.

Maize thrives best on loamy soil because it has a balanced mixture of sand, silt, and clay. This ensures good aeration, proper drainage, and high fertility, which are essential for healthy maize growth. Sandy soils drain too quickly and lack nutrients, while clay-heavy soils hold too much water, limiting root development.

Mineral sources in animal nutrition include fish meal, blood meal, and green pastures, all of which provide essential nutrients such as calcium, phosphorus, and iron. Palm oil, however, is primarily a source of fat and energy and does not provide significant mineral content. Therefore, it is not considered a mineral source for animals.