Six course rotation system
Reay Clark, a local farmer, tells us that Bonnar's transformation of his croft was due to using a system of farming; the Six course rotation system.
This system, in widespread use amongst Scottish crofters at the time, involved growing oats one year, turnips the next, oats again in the third year and then growing grass for the next three years, before beginning again with oats.
The key to the whole system was the turnip. Church congregations of the time were reputed to have been heard praying:
"Praise God in His mercy who sent us the turnip!"
The cultivation of turnips helped expose weeds, and provided essential winter feeding for the cattle.
Farmers then put sheep in the turnip field at the end of the year to clean it up and add fertiliser.
The three years of grass restored nutrients to the soil, exhausted by the three years of planting oats and turnips.
A popular crofter's saying, known by locals as the Crofter's Law, noted that:
"[the] more stock, the bigger the midden (dung heap), bigger the midden, the better the crops, better the crops the more stock you can keep"
Bonnar would use the dung from his cattle in the winter and plough it into the land in spring to fertilise the soil.