(a) A farmer purchased a tractor in the year 2000 for D 12, 000.00. In 2009, the tractor was sold for D 3,000.00 as it was no longer economical to keep. Cal...

(a) A farmer purchased a tractor in the year 2000 for D 12, 000.00. In 2009, the tractor was
sold for D 3,000.00 as it was no longer economical to keep. Calculate the:

(i)  useful life of the tractor;
(ii) salvage value of the tractor;
(iii) total depreciation of the tractor;
(iv) annual depreciation of the tractor.  

(b) Describe the following terms as used in agricultural economics:
(i)  demand schedule;
(ii) supply curve.  

(c) List four agricultural extension agencies in West Africa. 

(d) State four ways through which soils are enriched with nitrogen.

Answer Details

(a) (i) The useful life of the tractor can be calculated as the difference between the year it was purchased and the year it was sold.
Useful life = Year of sale - Year of purchase Useful life = 2009 - 2000 Useful life = 9 years
(ii) The salvage value of the tractor is the amount it was sold for when it was no longer economical to keep.
Salvage value = D3,000.00
(iii) The total depreciation of the tractor can be calculated as the difference between its purchase price and its salvage value.
Total depreciation = Purchase price - Salvage value Total depreciation = D12,000.00 - D3,000.00 Total depreciation = D9,000.00
(iv) The annual depreciation of the tractor can be calculated by dividing the total depreciation by its useful life.
Annual depreciation = Total depreciation / Useful life Annual depreciation = D9,000.00 / 9 Annual depreciation = D1,000.00
Therefore, the annual depreciation of the tractor is D1,000.00.
(b) (i) Demand schedule is a table that shows the various quantities of a product or service that consumers are willing and able to purchase at different prices, over a given time period.
(ii) Supply curve is a graphical representation that shows the quantity of a product or service that producers are willing and able to offer at different prices, over a given time period.
(c) Four agricultural extension agencies in West Africa are: - The West and Central African Council for Agricultural Research and Development (CORAF) - The National Agricultural Extension and Research Liaison Services (NAERLS) in Nigeria - The Department of Agricultural Extension Services (DAES) in Ghana - The Institut National des Recherches Agricoles du Bénin (INRAB) in Benin
(d) Four ways through which soils are enriched with nitrogen are: - Crop rotation: where leguminous crops such as beans and peas are grown and then plowed back into the soil to enrich it with nitrogen. - Green manure: where plants such as clover, alfalfa, or rye are grown and then plowed back into the soil to enrich it with nitrogen. - Animal manure: where livestock manure such as cow or poultry manure is added to the soil to enrich it with nitrogen. - Nitrogen fixing bacteria: where certain bacteria, such as Rhizobia, live in nodules on the roots of leguminous plants and convert atmospheric nitrogen into a form that plants can use.