The shape and size of any farmland can be measured or determined by farm surveying. The area of farmland varies; some are rectangular, square, triangular or even circular in shape. The formula used in the calculation of farmlands and plant population include:
a) Area of Farmland: This refers to the product of the length and width of the farmland measured in metres. Mathematically,
Area of farmland = Length x Width (metres)/(L x W)m
b) Number of Plant Stand/Plant Population: This refers to the number of plants in an area of farmland. Mathematically,
Plant population= Area of farmland (m2)/Spacing (m3)
c) Spacing: This is the distance between one crop plant and the next plant which is usually between and within the rows, e.g ., 60cm x 30 and 100cm x 75cm.
d) One hectare = 10,000m2. This figure means there are 10,000m2 in one hectare of farmland. This figure is always used when the area of farmland is given in hectare.
e) Measuring the Area of Farmland: The shape and size of any farmland can be measured or determined by farm surveying. The area of farmland varies as already noted above.
Formulae for calculating the area of farmland are shown below.
Example 1: If the length and width of a farmland are 60m x 30m respectively, and the spacing of a tomato crop plant is 30cm x 30cm, calculate:
- the area of the farmland;
- the plant population (tomato) in the given area;
- the total population if there are two plants per stand.
20,000 x 2 = 40,000 tomato plants
The total population = 40,000 tomato plants.
A school farm in Lagos State was surveyed and presented in a map. Use it to answer the following questions.
- What is the approximate area of the farm?
- If the farmland is used for pineapple production at a spacing of 2.5mx 2m, what will be the initial population of pineapple trees in the farm?
- If 8% of the pineapple plants were damaged by pests, what will be the final pineapple plants in the farm?
Note: The longest portion of the farm is 70m long.
- A piece of land to be used to establish a pasture of Stylosanthes gracilis was surveyed to be circular.
- If the radius of the land is 200m and the spacing of the pasture legume is 1 m by 50cm, what is the population of the legume at one seed per stand?
- If the germination percentage is 75, calculate the expected plant population.