### 1988 WAEC Agricultural Science Practical A farmer applied one-third of the required amount of N.P.K fertilizer to 2 hectares of...

Agricultural Science
WAEC 1988

A farmer applied one-third of the required amount of N.P.K fertilizer to 2 hectares of maize at the rate of 50 kg N.P.K, fertilizer per hectare, two weeks after planting.

Use the information above to answer questions (a) to (d) below:

(a) If the spacing of maize crops was 60 cm x 91 cm, calculate the plant population on the farm:

(b) Calculate the total quantity of fertilizer used on the farm.

(c) Calculate the amount of fertilizer applied during the first two weeks of planting the maize crops.

(d) Calculate the quantity of fertilizer applied per stand at two weeks.

##### Explanation

(a) Iha = 10$$^{4}$$m$$^{2}$$ or 10$$^{8}$$cm$$^{2}$$
plant popu./ha = $$\frac{10^{8} cm^{2}}{60 \times 91cm^{2}}$$ = 18315 plants

$$\frac{10^{8} cm^{2} \times 2}{60 \times 91cm^{2}}$$

= 18,315 x 2 = 36,630 plants

(b) Total amount of fertilizer required for the farm;
Rate = 50kg / hectare
For 2 hectares = 50 x 2 = 100kg

(c) Amount of fertilizer applied at the first two weeks of planting;
Rate = 50kg / hectare
Total = 100kg for 2hectares
Required for the first two weeks = $$\frac{1}{3}$$ x 100kg = 33.3kg of NPK fertilizer

(d) Quality of fertilizer per stand at two weeks
= $$\frac {\text {Quantity of fertilizer}} {\text {No of Stands}}$$ = $$\frac {33.2 \times 100 {\text {grams}}} {36,630}$$ = 0.9gm or 1.00gm