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Cycle 7 (2018 Deadline)

Increasing the adoption of nutrient management innovations by Cambodian vegetable farmers

PI: Leangsrun Chea (, Royal University of Agriculture (RUA)
U.S. Partner: Zachary Stewart, Feed the Future Innovation Lab for Collaborative Research on Sustainable Intensification, Kansas State University
Dates: February 2019 - January 2021

Project Overview

Vegetable production in Cambodia is largely constrained by access to fertilizer and water. Given that the humid tropical soils of Cambodia are highly weathered, crop nutrient availability tends to be relatively low. Soil amendments such as cattle manure, farmyard compost, and locally available fertilizers are applied in limited amounts to improve soil properties, but mineral fertilizers are usually not affordable by subsistence-oriented farmers, leading to widespread nutrient deficiency in smallholder vegetable crop production. Farmers often attempt to supplement the available nutrients in the soil by applying manure, but household manure availability varies greatly depending on the magnitude of livestock integration in the local production systems. Therefore, manure applications often do not meet plant nutrient demands. This loss in productivity, combined with reduced access to available resources and technology, subsequently exacerbates the food insecurity of rural smallholder farmers. Farmers often feel uncertain about how much manure and/or mineral fertilizers to apply in order to maximize yield and profitability. Inappropriate nutrient management often results in low yield and poor nutritional quality of the vegetables produced and inversely can have negative environmental consequences. Therefore, proper nutrient management practices are essential for Cambodian vegetable farmers to ensure the successful production of quality vegetables. Several fertilizer recommendations for horticultural production currently exist; however, adoption has remained low, and fertilizer under and over supply is common. There is need for the incorporation of bidirectional learning in the research and dissemination pathway that allows farmers to experiment with new fertilizer recommendation innovations and that learns from farmer feedback to adapt the innovation to better match their needs.

Currently, through the financial support provided by USAID through the Feed the Future Horticulture Innovation Lab, the project “Multidimensional Trade-off Analysis of Integrated Animal-Horticulture Farming Systems for Improved Smallholder Farmer Adoption Recommendation” is conducting on-station vegetable nutrient management trials that will improve nutrient management recommendations of both inorganic and manure based fertilizers. The current PEER project addresses a significant need for additional research and extension activities that promote the uptake and adoption of this nutrient management decision support innovation. The project is intended to disseminate the adaptive results of the previously conducted research to farmers and extension agents. Even when appropriate fertilizer recommendations have been developed, there are still many barriers preventing their adoption and use. Bidirectional learning between scientists and extension workers and farmers is a critical process in overcoming these barriers and increasing technology adoption, and the current PEER project is aimed at facilitating those efforts. Through the adoption of optimized and efficient nutrient management for vegetable crops, Cambodian farmers will be able to improve their vegetable production efficiency and, ultimately, their vegetable productivity and profitability. The innovation will help diversify household diets and enhance income generation by supplying vegetables to markets. This innovation also minimizes negative impacts on the environment by reducing nutrient losses through runoff and leaching due to over application.

7-79 Chili Farmer Interview7-79 Mulch Interview
Project team members interview farmers growing chili More interviews with farmers and her perception of living mulch (photos courtesy of Dr. Chea)
Summary of Recent Activities

The main activities during the first quarter of 2020 included continuation of an on-station trial at the CE SAIN technology park at RUA and identification of farmers who are interested in on-farm trials. The on-station trial began in December 2019, and from January through March PEER team members collected data weekly for plant growth evaluation such as plant height, stem diameter, branch number, and leaf chlorophyll index. They also tracked the number of days from planting to flowering and to fruit maturity. In March, the researchers collected leaf, fruit, and soil samples for analyses. The leaf and fruit samples will be sent to the University of Goettingen, Germany, for mineral analyses and fruit nutrition quality determination, while the soil samples are being kept for analyses at RUA. So far, the team has identified 29 farmers from three districts in Siem Reap Province who are interested in implementing on-farm trials to compare their existing technologies with Arachis pintoi living mulch. Among those farmers, 21 are women who take the lead in vegetable cultivation in their families. The farmers received Arachis pintoi cuttings and training on how to use them in cultivation and integration with vegetable crops. Due to restrictions associated with the coronavirus pandemic, there have been some delays in sending the leaf and fruit samples to the University of Goettingen for analysis. Direct farmers’ field visits also became impossible in late March, but team members provided follow-ups to farmers by phone instead.

In the second quarter of 2020, the researchers will conclude the first crop cycle of the on-station experiment and will begin the second crop cycle cultivation in May. They will make regular measurements of plant growth and will continue working the farmers’ field trials, including obtaining first-hand feedback from the participating farmers on their experience with Arachis pintoi adoption.

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