Agricultural Science 2019 Jamb Examination

Fertilizers are added to fishponds to supply nutrients that promote the growth of plankton. Plankton, which include phytoplankton and zooplankton, form the base of the aquatic food chain and serve as natural food for fish. Fertilizers are not direct food for fish, nor do they act as bait or water purifiers.

New Zealand White, Chinchilla, and Californian White are well-known breeds of rabbits. 'Landrace' is not a rabbit breed; it refers to certain pig breeds that have been selectively bred. Therefore, Landrace is the odd one out in this list.

The reproductive system of a hen consists of the ovary and oviduct, which includes the funnel (infundibulum), magnum, isthmus, uterus, and vagina. The ureter, however, is part of the excretory system responsible for carrying urine from the kidney to the cloaca, not part of the reproductive system.

Good silage must retain its nutrients, adequate moisture, and fibre for proper digestion. However, it should be free of moulds, since mould growth indicates spoilage and leads to toxins that make the feed unsafe for animals.

Wind is considered the most unreliable source of power on the farm because it is not constant and depends heavily on weather conditions. In contrast, heat engines, electricity, and animals provide more predictable and controllable sources of power.

The correct machine for sowing seeds and applying fertilizer simultaneously is the seed drill or fertilizer drill, which is associated with ploughing operations in mechanized farming. Ploughing prepares the soil while the drill enables the placement of seeds and fertilizers efficiently in rows. Land clearing, threshing, and harrowing serve entirely different purposes such as land preparation, separating grains, and breaking clods respectively.

Wind, bulls (animal power), and tractors are valid sources of power for farm operations. A plough, however, is an implement that requires power from an external source such as animals, tractors, or humans, and therefore is not itself a power source.

Cross staff, Abney level, and chain are recognized tools used in land surveying. A 'datun' is not a survey instrument but refers to a chewing stick in local contexts. Hence, it does not belong in the list of survey equipment.

Daily maintenance of a tractor is essential to ensure smooth operation. Engine oil must be checked daily because insufficient lubrication can cause overheating and engine damage. Spark plugs, air cleaners, and batteries are important but do not require daily checking in the same way as engine oil does.

Cultivating more varieties of crops helps ensure food security by diversifying food production and reducing dependence on a single crop. This approach minimizes the risks associated with pests, diseases, and unfavorable climatic conditions, as losses in one crop may be compensated for by others. It also improves nutrition since different crops provide a variety of nutrients, thereby addressing malnutrition and food shortages.