Agricultural Science 2021 Jamb Examination

Farm implements are tools or mechanical devices used to carry out agricultural operations such as planting, harvesting, spraying, or weeding. While dryers, shellers, and mowers are machines or equipment used for post-harvest or cutting purposes, a mistblower is specifically designed for spraying pesticides or herbicides on crops, making it a farm implement.
Hence, mistblower is the correct answer.

Periodic maintenance involves regular servicing actions that keep machinery in good working condition over time. Cleaning after use is part of routine periodic maintenance, as it prevents dirt buildup and corrosion, ensuring the longevity of the tractor. The other options are daily checks, not periodic tasks.
Therefore, cleaning after use qualifies as periodic maintenance.

In West Africa, animal power remains the most versatile and accessible source of farm power. Animals like oxen and donkeys are used for ploughing, transportation, and other farming activities. Biogas, wind, and water power are limited due to infrastructure and geographical factors.
Hence, animal power is the most versatile source in the region.

Farm surveying involves measuring and mapping out land areas using tools like the Abney level for determining slope, compass for directions, and Gunter’s chain for measuring distance. A spade, however, is a digging tool used for soil preparation and not for surveying purposes.
Therefore, spade is not a surveying equipment.

Leasing refers to a contractual arrangement in which a farmer is allowed to use a piece of land for agricultural purposes over a specified period in exchange for rent or payment. It differs from inheritance, gift, or compensation as it is temporary and based on agreed terms.
Thus, a leased land is given for a specific period on a rental basis.

Inheritance-based land tenure often causes land fragmentation, family disputes, and difficulties in land transactions. However, one advantage of inherited land is that individuals have the right to freely use and control it without paying rent or seeking permission.
Therefore, the right to free use and control is not a problem associated with inheritance.

When rocks are subjected to repeated heating during the day and cooling at night, their outer layers expand and contract alternately. This process weakens the rock’s structure, leading to cracking and breaking apart into smaller pieces. This phenomenon is known as fragmentation or exfoliation.
Hence, alternate heating and cooling of rocks result in fragmentation.

Biotic factors are living components that affect agricultural production, such as pests, parasites, and decomposers. Abiotic factors include non-living components like soil pH, topography, and soil texture. Parasites are living organisms that harm host plants or animals, making them biotic factors.
Therefore, parasite is the biotic factor among the options.

Shifting cultivation is a traditional farming system where a farmer cultivates a piece of land for a few years and then abandons it to allow natural regeneration of soil fertility before returning later. Crop rotation and mixed cropping involve continuous use of the same land but with varied crops.
Hence, shifting cultivation fits this description.

The percentage water content of a soil sample is calculated using:\[ \text{Water Content} \]\[= \dfrac{\text{Fresh Weight} - \text{Dry Weight}}{\text{Dry Weight}} \times 100 \]Substituting the values:\[ = \dfrac{180 - 120}{120} \times 100 \]\[= \dfrac{60}{120} \times 100 = 50\% \]However, water content is usually expressed relative to the wet weight:\[ = \dfrac{60}{180} \times 100 = 33.33\% \]Thus, the correct percentage water content is 33.33%.