Improvement of vegetable production and postharvest management systems in Cambodia and Australia

• Cambodia Agricultural Research and Development Institute, Cambodia
• Department of Agronomy and Agricultural Land Improvement, Cambodia
• Department of Planning, Statistics and International Co-operation, Cambodia
• Charles Sturt University, Australia

The Cambodian Government has been keen to support a growing trend of crop diversification amongst farmers. Traditionally rice has been the main crop grown, but diversification has increased since the country attained rice self-sufficiency. Despite this, vegetable production remains very low - largely due to unreliable supply of seed, high input costs and a lack of knowledge of postharvest handling. Per capita consumption is amongst the lowest in Asia, so the industry has a large potential for growth. The most urgent requirements for vegetable improvement in Cambodia have been identified as:
availability of cultivars with resistance to diseases, pests and high temperatures;
enhanced understanding of the deficiencies and options for improvement of vegetable supply chains;
practical and low-cost technologies to improve crop yields and quality;
postharvest handling and pest management to reduce pesticide residues and provide more effective control measures.
The Asian Vegetable Research and Development Centre (AVRDC) has active breeding and crop improvement programs in tomatoes and chilli that were suitable for inclusion as target crops in the project.

The three main project objectives are: 1) to map supply chain constraints, devise improvements and incentives for improving product marketability in the Cambodian vegetable industry; 2) to develop and demonstrate improved production and postharvest strategies that will underpin quality improvement and industry development; 3) to improve Cambodia's R&D capacity in vegetable research.

The researchers are working to establish a model for improved production and supply chain performance for the Cambodian vegetable industry. They are investigating and implementing changes to the production and postharvest handling and storage of vegetables, commencing with high-performing, disease-resistant tomato lines from the current AVRDC-Cambodia collaboration. Selection of tomato as the initial 'model' crop reflects the recognised ongoing importance of this crop for Cambodian producers and will give opportunities to maximise the benefits arising from the AVRDC breeding program and to focus on the current quality differential between local and imported produce available in the marketplace. Other important vegetables such as chilli and leafy brassicas are to be considered later in the project. Chilli is an important vegetable for fresh and processing markets in Cambodia, while leafy brassicas, although popular in the Cambodian diet , are perishable and market product is highly variable in quality.
The scientists are mapping both production and postharvest components, and identifying potential supply chain champions from both these sectors. A critical component is a study of the value chain of vegetables marketed in Cambodia. Better information on the value added at various points along the supply chain (who, what, how, where, why) is vital for devising more efficient marketing channels that will ultimately bring better returns to growers. Matching this information with other supply chain studies that have identified where loss of product value occurred through poor postharvest handling and storage is helping provide baseline information for calculating economic feasibility/value of improvements and encouraging their uptake, to help make Cambodian products more acceptable in the marketplace.

Research products developed over the 3 years of the project include open-pollinated, heat-tolerant tomato and chilli varieties suitable for Cambodian conditions, suitable crop management practices (irrigation and fertiliser), recommendation guidelines for postharvest handling and storage of vegetables, and capacity building for vegetable research in Cambodia.
Potential impacts of the research on vegetable production in Cambodia are extensive, given the technologies are likely to reach a wider audience of growers than just the three provinces the project was centred around (Takeo, Kompong Thom and Kampot). It is too early to evaluate the adoption of the technology packages, but farmers at field days during the project review displayed considerable interest in field demonstration trials.
The Cambodian research teams have developed skills for undertaking research on vegetable production and postharvest handling. Those skills include their knowledge on how to conduct small plot, replicated studies such as varietal screening, fertiliser and irrigation trials, collection and analysis of socio-economic data, postharvest research, and collection/identification of some common pests. The most technically complex discipline requiring considerable specialist skills and training is plant pathology, and progress in this area is commendable.
There is a notable economic improvement for farmers who have adopted the technology packages. The most clearly demonstrable social impact was the cooperative and enthusiastic interaction between farmers and researchers. The trial of a simple, low-pressure, low-cost drip system originally developed in India was shown to use up to 30% less water, while improving vegetable yields by up to 25% compared to standard practice. However, adoption seems unlikely to be rapid as the system costs US$50, which is still considerable for most small growers.
Recommendations for future research focus on the choice of at least on one prioritised vegetable crop for each of the following groups: leafy (Chinese kale and other brassica vegetables), fruit (tomato and chilli) and tuber/root (potato and carrot) vegetables.
Basic agronomy trials, in both the current crops and those new crops selected for inclusion in future research, need to continue. Improved drainage with better bedding systems, and use of both synthetic and organic manures to determine how to achieve the most cost-effective production, are two obvious areas for further work. The IDE drip system is conceptually good but may benefit from some modification and needs to be more rigorously tested alongside more conventional (emitter) drip systems.
For vegetable production in Cambodia to improve, research must address biotic factors limiting yield and reducing produce quality. Disease in particular, as well as insect and to a far lesser extent weed management were nominated by farmers as key production limitations at village sites where trials were visited. Crop protection chemicals were widely used but the farmers understood little about what they were or how to use them effectively.
Postharvest research should focus on improving the produce shelf-life by using scientifically tested simple and affordable storage techniques built on client's available resources. As well there is a crucial need for a network of vegetable seed producers to aid technology adoption and create project impact at a reasonable scale.