Unveiling constraints to cassava production in Cambodia: An analysis from farmer's yield variations

Cassava (Manihot esculenta Crantz) is currently the most important upland crop of Cambodia, but information on yield variations and causal factors which is important for efficiently targeting efforts to increase production is still lacking. The objectives of this study were to determine the yield variations and causal factors for cassava production in Kampong Cham province in Cambodia. Forty five households in four production zones were selected for the study. A farm survey employing semistructured interviews, combined with field visits, were used for the collection of information on farmers’ practices in cassava cultivation, while crop cutting was done to provide estimates of cassava yields. The data were analyzed for yield variations,yield gaps and causal factors. The results showed large variations in yield among farmers’ fields, ranging from 12.7 to 37.2 t ha -1 . The fields were divided into five yield categories, with the mean yields of the lower four categories ranging from 76.0 to 34.2% of the maximum yields, with corresponding yield gaps ranging from 8.9 to 24.4 t ha -1 . The main yield constraints identified were soil nutrient deficits, short crop duration and weed competition. The highest yielding fields had no production constraints, but the number and/or the level of constraints increased in fields with lower crop yields. However, for different fields with similar yield levels, the main production constraints sometimes differed. The results clearly indicated that there are opportunities for yield improvement and narrowing of yield gaps through the adoption of field specific improved technologies and management practices.