Agricultural Science 2019 Jamb Examination

Surface irrigation methods rely on gravity to distribute water over the soil surface. Examples include natural flooding, basin or check flooding, and furrow irrigation. Sprinkler irrigation, however, involves pressurized water sprayed through nozzles to simulate rainfall and does not fall under surface irrigation.

Unlike fungal and bacterial diseases, viral diseases in plants cannot be effectively controlled through chemical sprays. The most effective strategy is to plant resistant or tolerant varieties, which have been bred to withstand viral infections. Other methods such as crop rotation or burning infected plants may reduce spread but do not provide lasting protection.

Thinning is the process of reducing the number of seedlings in a stand to the desired population density. In maize farming, if too many seeds germinate in one spot, excess seedlings are removed, leaving only the strongest plants. This practice ensures proper spacing, better access to nutrients, water, and sunlight, and improved crop yield.

Maize rust is caused by fungal pathogens such as *Puccinia sorghi*. The fungus produces characteristic reddish-brown pustules on leaves, which interfere with photosynthesis and reduce yield. It is not caused by nematodes, insects, or bacteria.

A capsule is a dry, dehiscent fruit that splits open when mature to release seeds. Okra produces a capsule fruit that contains multiple seeds. In contrast, apple is a pome, mango is a drupe, and coconut is also a drupe.

The head of a tapeworm is called the scolex. It contains suckers and sometimes hooks that attach the parasite to the intestinal wall of its host. The rostellum is a protrusion that may carry hooks, while suckers and hooks are structures present on the scolex, but the overall head is termed the scolex.

Forage crops are cultivated mainly to provide feed for livestock. They include grasses and legumes such as alfalfa, clover, and Napier grass, which are either grazed directly by animals or cut and stored as silage or hay. Vegetables and cereals are grown mainly for human consumption, while shrubs are not considered primary feed sources.

Heat (estrus) in animals is characterized by signs such as restlessness, mounting behavior, and mucous discharge from the vulva. Discharge from the rectum is abnormal and is not associated with heat. This makes option A the one that does not fit.

Turkeys, like chickens and other poultry, have a fixed incubation period that represents the time it takes for eggs to hatch once incubation begins. For turkeys, this period averages 27–28 days under proper conditions of temperature, humidity, and turning. This is longer than the chicken incubation period (21 days) but shorter than that of some waterfowls. The length of time ensures full embryonic development before hatching.

Farm credit comes from institutions specifically designed to support agricultural activities. Agricultural banks provide specialised loans for farmers. Government agencies often provide subsidised credit schemes. Cooperative societies pool resources from members and make them available as loans. Mortgage banks, however, are focused on housing and real estate financing and do not generally provide agricultural credit.