### Outside work: get a feeling for a hectare and how much arable land there is.

If you have never tried it, this exercise, which can be done with schoolchildren, is quite enlightening, and something you can map out on the school playing field:

One hectare can be easily understood if you are a small group and stake it out in a fairly large open space. Imagine you are at the center of one hectare: it is 50 meters to each side, and 70 meters to each corner. One metre is about the length of one pace. You can put a tape measure down to get a feeling for one meter to do this exercise.

With a few friends and sticks you can pace out one hectare, 10,000 m^{2}. Put sticks in each corner.

The amount of arable land available to each person is 0,23 of a hectare. That works out at just less than a quarter of the area mapped out.

GiIven you have just mapped out one hectare as 100X100m.

Given the amount of arable land per person is 0,23 hectare.

Calculate how many meters by how many meters this is.

Pace it out to try it. Stand in it and see how it feels.

And, if you know how much arable land per person that is available in your country, and you have staked out one hectare, get that number of people into the square. Stand there, look at the area and each other to get a feeling for the size and scale of what you as a group would need to take care of if this was all you had.

- What does this tell you about food security in your country?
- Find out the expected population rise for 20 or 30 years ahead
- Given the above figures, calculate how much arable land there will be per person.
- Work out how many people per hectare of arable land that represents
- Get that number of people with you into the square you set up. Take a photo. Make some notes about what you discussed might be the consequences of this population rise.

More work

Th e number of humans supported per hectare of

arable land has increased from 1.9 to 4.3 persons between 1908

and 2008 (Erisman et al., 2008 )

Make a time line and make photos to illustrate each point in time to illustrate what has happened to make this support possible (e.g Haber-Bosch process, tractors,etc)