Primary School Agriculture: Volume I: Pedagogy (GTZ, 1985, 144 p.)
 Part III: Examples for practical use
 2. Lesson notes
 2.1 Lesson notes on tephrosia 2.2 Lesson notes on rice 2.3 Lesson notes on Land Tenure in Kake-Bakundu 2.4 The integration of agriculture and mathematics

2.4 The integration of agriculture and mathematics

(some more examples)

Another problem is taken from the observation of planting distances on a maize plot at a school farm. Two rows planted by different pupils according to the same standard planting distance - 25 cm - have been measured after germination. The results are as given in the next table.

 Row APlanting Distance in cm Row BPlanting Distance in cm 27 24 27 26 28 23 35 27 29. 25 22 25 33 26 32 26 29 25 31 26 38 32 30 22 32 25 29 27 30 25 28 23 34 24 33 25 35 22 24 27 27 25.5 33 30 24.5 25 26.5 25 25.5 26 24 29 Average: 30.27 cm Average: 25.5 cm Range: 38-22=16cm Range: 32-22 = 10cm 22 1 24 1 27 3 28 2 29 3 30 2 31 1 32 2 33 3 34 1 35 2 38 1 Total 22

If a measuring rod marked with centimeters is available measuring is quite fast. It shows how despite a standard planting distance (25 cm) obtained by using a stick cut to size, the actual distance can be consistently greater or smaller - ask for the reasons (fatigue, wish to get the work done quickly, planter being rushed, wrongly cut stick, insufficient routine), and that even where on average the standard distance is well approximated, there are variations due to some or all of the factors outlined above.

Problems:

1. Which planting distances occur several times? How often do they occur?

Group identical measurements and order them according to size. The second table shows how this would be done for row A.

Make a bar chart. You might group the measurements still further, e.g.
22-24 cm
25-27 cm
28-30 cm in order to have fewer bars in your chart and larger numbers for each bar.

2. Calculate the average planting distance in each row.

3. Using the range (highest planting distance - lowest planting distance in each row) determine which pupil has been the more accurate in his planting.

The third problem was formulated after a class had measured a farm plot that had just been tilled. Twelve ridges were ready for planting. On p. 136 is the table of measurements.

Problems:

1. Calculate

- the average length of the ridges,
- the average width of the ridges,
- the average height of the ridges,
- the average width of the furrows.

2. Make a scale drawing showing each ridge.

3. What is the length and the width of the total plot?

4. What is the average area per ridge? (average length x number of ridges)

5. What is the net planting area of the plot? (average area x number of ridges)

 Ridge No. Length Width Height Furrow m cm m cm m cm m cm 1 5 56 90 65 2 5 30 90 21 65 3 5 60 74 35 61 4 4 60 65 20 40 5 5 56 90 12 65 6 5 30 90 21 65 7 4 60 90 23 64 8 5 35 85 30 60 9 4 34 80 20 65 10 4 60 1 17 21 65 11 4 34 80 20 64 12 3 - 1 - 21 65