The economics of rice double-cropping with supplementary irrigation in the rainfed lowlands of Cambodia: a survey in two provinces

摘要

The use of small-scale, supplementary irrigation is seen as a potential method to overcome a severe constraint in rainfed lowland rice production, permitting a move from single- to double-cropping and thus improving food security and farm incomes. InCambodia, a single rice crop grown on infertile soils under unfavourable climatic conditions is the most common practice. With poor yields and low levels of land use, farmers regularly experience food shortage and poverty. Based on supplementary irrigation from privately owned tube-wells or on-farm reservoirs, farmers in some areas have been able to grow an additional, short-term rice crop at the start of the wet season using modern varieties. In this study, the effect of double-cropping on farm incomesand on the use of farm resources were assessed, and farm-level constraints to the adoption of double-cropping identified. A survey was conducted in two locations in southern Cambodia, one in Takeo Province where conditions were favourable for supplementary irrigation, and one in Kampot Province where conditions were less favourable. Data about production practices and the costs and returns of single-cropping and double-cropping were collected by interviewing 115 randomly selected farmers. It was foundthat moving to double-cropping could increase food supply by 75% in Takeo and 22% in Kampot, and farm family income by 37% in Takeo and 25% in Kampot over a full farm-year. This was achieved mainly by using farm resources better, with land use of 150% inTakeo and 122% in Kampot. Using wells and pumps for supplementary irrigation improved returns in Takeo, whereas farmers in Kampot were limited by their reliance on surface storage. Thus, a lack of tube-wells and pumps to access groundwater is the key obstacle to expansion of the double-cropping area, both within and between regions.