1Cambodian Agricultural Research and Development Institute (CARDI), Ministry of Agriculture Forestry and Fisheries (MAFF), Phnom Penh, Cambodia.
2System Approaches in Agriculture Program, Departments of Plant Science and Agricultural Resources, Khon Kaen University, Khon Kaen, Thailand.
3International Center for Tropical Agriculture (CIAT), Bangkok, Thailand.
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.