On the face of it, my assignment was simple. Photograph the farmers of the world. National Geographic was undertaking an eight-month series about the vexing problem of feeding nine billion people when the great tide of human population crests in the year 2050.

My picture editor Dennis Dimick had set the agenda: show us the people who feed the planet. Face to face. Let us look into their eyes and see who they are. Meet them, know them as real people, not just visual ciphers for agricultural jargon. Farmers, particularly in the third world, are often portrayed as objects, ubiquitous and faceless, without personal stories. The fodder of statistics and spreadsheets.

Which is how I came