In fact, in three months spent in Liberia, I never saw a man farming cassava. Rubber, yes and sometimes rice, but cassava farming is "women's work". Notice how the men in the picture below are 'supervising' (i.e., sitting around) while the women are busy. 
Sometimes I imagine that the gender division of employment in agriculture will change as countries become more developed. But maybe not. I have been walking around rural Yorkshire in the last week, where there are a lot of sheep farms. Without exception, the farmers riding around the hills in Land Rovers and quad bikes are men. Maybe men only get involved when there are machines to play with?
