Data were collected on management practices, soil properties and crop yields in cassava fields of the sample households in each selected village.
Additional data on daily rainfall, maximum and minimum temperatures and humidity for the study period (2009-2010) were also obtained from the Kampong Cham Provincial Department of Meteorology and Water Resources.
A farm survey employing a semi-structured interview, combined with a field visit, was used in collecting information on farmers’ cassava practices for the individual sample households.
Crop sampling was used to measure cassava yield for each field, while soil samples were taken for laboratory analysis.
The farm survey, soil sampling and crop cutting were conducted during the period of December 2009 to February 2010. Initially, it was planned to collect data for 12 fields within each zone, one field for each household.
However, early harvesting of the cassava crop by some farmers resulted in the crop cuts for yield measurement being restricted to only 10 fields in Zone 2 and 11 fields in Zone 4. However, in Zones 1 and 3, 12 fields were sampled as planned. A total of 45 households were covered
by the survey and crop cutting, with the number of farmers in each village representing 70-80% of the cassava growing households in the village. Prior to the survey, the commune and village leaders were approached to get permission to conduct the survey, and to obtain secondary information on cassava growers in the village, together with their past yield records.
Farmers were stratified-randomly selected to provide representative samples of households which had recorded high and low cassava yields in the past.
Farmer collaborators had to indicate a willingness to be interviewed and allow the sampling of their cassava crops.