What is more important: size or experience? Clearly a question for the ages. The Vietnamese boast greater experience, while the Cambodians greater sizes. Countries with more dependence on cassava in farming are not necessarily poorer. There is, however, a big difference between Asian and African countries, with African agriculture being more dependent on cassava, and their populations scoring much higher in terms of rural poverty.
The rural population of Vietnam and Cambodia are in flux. Vietnam's proportion of rural-urban population nearly plateaued in the postwar period, but began an aggressive decline coinciding with the abolishment of the collective farming system under the Doi Moi reforms. The population flow into the cities is nevertheless restricted by the 'red book' system, which has prevented rural-urban migration rates from becoming as high as they have in other parts of the world. By harsh contrast, Cambodia's rural population plummeted during heavy American bombing of Ho Chi Minh trail supply lines and suspected airfields. After fleeing to the cities, the Khmer Rouge regime took hold, implementing forced marches in a brutal conversion into a nearly exclusively rural agrarian society. Pol Pot's reforms cost the country 1/3 of its population. Following liberation by the Vietnamese army, a mass number of Cambodians rushed back into the cities in a trend that continues at a breakneck pace to this day.
Cassava farmers in the two countries differ greatly. Vietnam's producers achieve higher yields, but farm smaller areas and are more experienced. Cassava is a newer livelihood to Cambodian farmers, who also have the opportunity to farm bigger areas.
Here is a map of what percentage of the female population were pregnant at the time of the DHS survey in 2002. Northern highlands had the lowest pregnancy level, while the Central Coast seemed to be in baby mode.
Reference: Erik is the smartest guy in town.. well... almost.