My friend Mike Mortimore, who has died aged 80, was a pioneering geographer who lived and worked in the dry lands of west Africa. He was motivated by a love of the people in that region, northern Nigeria in particular, believing that human endeavour could build sustainable livelihoods.

Mike was the eldest of three children born in Bermuda. His father, John Mortimore, was employed by Cable & Wireless, and his mother, Dorothy (nee Taylor), travelled the world with him. Mike was sent to Britain to attend Monkton Combe school, near Bath, where he enjoyed rowing and cycling. The Christian ethos of the school led him to a faith that would shape his life.

After Monkton he studied geography at Leeds University, meeting his future wife, Julia, at the Christian Union there. He graduated in 1962 and left for Zaria in arid northern Nigeria, where he helped set up the geography department of Ahmadu Bello University. Julia joined him as soon as she could and they stayed for 25 years.

Mike’s research focused on life on the margins: he documented the strategies used by farmers to adapt to drought, or the risk of drought. On one trip into the bush during the 1968-73 Sahel famine, a puncture led them to unload their cargo of grain sacks to get to the spare tyre of their Land Rover. When they drove away, Mike saw an old man emerge from behind a thorn bush and begin to pick up the individual grains spilled from the sacks. This, Mike realised, was what real starvation looked like. The incident had a profound effect on him.

His fieldwork challenged the orthodoxy that population growth and inefficient agriculture were driving the encroachment of the Sahara desert: in a series of books he argued that traditional agricultural systems could be good for the land. In the 1990s, he moved his attention to Kenya, and co-wrote More People, Less Erosion, whose message was that it is farmers who keep erosion at bay.

Mike moved to take up a professorship at Bayero University, Kano, in 1979, but a fourth child and the educational needs of their growing family gradually pulled them back to Britain the 80s. Once they had settled in Somerset, Mike continuedto work on international development research for bodies including Cambridge University and the Overseas Development Institute.

He and Julia were stalwart members of their parish church. He was working (and cycling) into his 80th year; his last book was a compilation of recent research, The End of Desertification.

He is survived by Julia, their children, Sally, Jo, Nick and Rachel, by 10 grandchildren and by his sister, Julia, and brother, Robin.