Agricultural Science 2019 Jamb Examination

Rice requires nursery practices because the seeds are first sown in a controlled nursery bed where they can germinate and develop strong seedlings. These seedlings are later transplanted to the main field, which allows better crop establishment, reduces weed competition, and ensures higher yield. Other cereal crops like maize, millet, and guinea corn are usually sown directly into the field without the need for nursery practices.

Groundnut typically matures within 4 to 5 months depending on the variety and growing conditions. This duration allows the pods to develop fully underground and ensures maximum oil and protein content. A shorter period such as 1–2 or 2–3 months is not sufficient for pod formation, while 6–7 months would be too long, leading to deterioration.

Oil palm thrives best in soils with a slightly acidic to neutral pH range of 5.5–6.5. This range allows for optimal nutrient availability, root development, and growth. Extremely acidic soils (pH below 5) hinder nutrient uptake, while alkaline soils (pH above 7) may reduce micronutrient availability and impair growth.

The best cold storage temperature for yam tubers is about 7°C. At this temperature, sprouting and microbial decay are minimized, prolonging the shelf life of the tubers. Higher temperatures such as 13°C or 15°C increase the risk of sprouting, while very low temperatures can cause chilling injury.

Dura, Tenera, and Pisifera are genetic forms of oil palm. Dura produces thick-shelled fruits, Pisifera produces shell-less fruits, and Tenera is a hybrid of Dura and Pisifera with thin shells and high oil yield. These varieties are important for commercial oil palm production.

Cowpea is a leguminous crop grown mainly for its protein-rich seeds, which are used as food rather than for oil extraction. In contrast, coconut, beniseed, and melon are classified as oil crops because they yield significant amounts of edible oil when processed.

Tenera is a hybrid variety of oil palm developed from crossing Dura and Pisifera. It is highly valued because of its thin shell and high oil yield. Amelonado and Trinitario are cocoa varieties, while Acuminata is a banana variety.

Maize requires sufficient nutrients during its early growth stages for proper root and stem development. Fertilizer application should be completed before the knee-high stage to ensure that nutrients are available for tasseling, silking, and grain formation. Late application reduces effectiveness and may lead to poor yields.

Coffee grows best in slightly acidic soils with a pH between 6.5 and 7.5. This range supports proper root function, nutrient availability, and microbial activity. Soils that are too acidic (below 6.0) reduce nutrient uptake, while overly alkaline soils may cause deficiencies that limit growth and yield.

Boron (B) is one of the least mobile nutrients in plants. Once it is deposited in plant tissues, it cannot be easily moved to other growing parts. This immobility means that deficiency symptoms appear first in the younger tissues and growing tips because boron absorbed earlier cannot be redistributed to meet new demands. Other nutrients like Mg, K, and P are relatively mobile and can be translocated from older leaves to younger ones during periods of deficiency.