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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 major activities during the first year of this project, which began in February 2019, included student and support staff recruitment, field visits to previous relevant USAID-funded project sites, a baseline survey, and the on-station experiment. A technician (female) was recruited to support the overall project activities, mainly involving implementation of the baseline survey, on-station trials, farmers’ field trials, and the farmers’ adoption study, as well as assistance in supporting the undergraduate and graduate students. One graduate Master’s student and three undergraduates (two of them female) were recruited to work on the project, and they will use the results for their theses. They have received training and hands-on experiences in field survey implementation, experimental design, data collection, and data management.

In addition, U.S. partner Dr. Zach Stewart had the opportunity to visit Cambodia, which allowed him to meet Mr. Chea and his team in person, discuss the activity plan, and visit the previous USAID-funded project research sites. The researchers visited sites of the Horticulture Innovation Lab-funded project “Multidimensional Trade-off Analysis of Integrated Animal-Horticulture Farming Systems for Improved Smallholder Farmer Adoption Recommendation” in Battambang and Siem Reap Province. Through this field visit, they identified the living mulch Arachis pintoi as a promising technology that could benefit farmers in terms of weed and nutrient management in vegetable crops. Therefore, the team included some questions in their baseline survey to gauge general understanding of this living mulch. The baseline survey was conducted to understand farmers’ current management practices for vegetable nutrient management and to obtain their perceptions on the living mulch Arachis pintoi in their vegetable crop production. The PEER team interviewed 155 households in four districts in Siem Reap Province. These districts are the main vegetable supply sources for Siem Reap Province, with some of the produce also being supplied to nearby provinces. In drafting the questionnaire, the team included important aspects such as farmers’ annual vegetable crop patterns, nutrient inputs, harvest amounts, knowledge of soil quality evaluation and improvement, and understanding of the living mulch Arachis pintoi. In this effort and in the selection of the districts to be surveyed, they relied on input from discussions with key farmers in Siem Reap. The preliminary results from baseline survey revealed interesting insights on the farmers’ use of fertilizers, as well as the costs of weed management both in labor and financial resources. It appears there is a need to improve management practices to optimize nutrient use and minimize cost and labor requirements for weed management.

Based on these results and the team’s consultations both with key farmers and their U.S. partner, they established an on-station trial at the technology park of the Center of Excellence on Sustainable Agricultural Intensification and Nutrition (CE SAIN), located at the Royal University of Agriculture in Phnom Penh. The objective of this trial is to assess the interactive effect of living mulch and phosphorus fertilization levels on soil quality and nutritional quality of the chili pepper crop. The trial will continue for two crop cycles until July 2020. The team’s goal is also to showcase nutrient management and living mulch technology to technopark visitors. The researchers are currently collecting data on crop growth, yield, nutritional quality, and soil quality. One undergraduate student and one Master’s student are involved in this experiment for their theses, eventually Mr. Chea and his colleagues aim to publish their results in an international peer-reviewed journal.

The major activities during 2020 include continuing the on-station trials, conducting farmers’ field trials, and carrying out a farmers’ adoption study. The PI and his group will collect the data from the on-station experiment, analyze soil samples at the Royal University of Agriculture, and send the plant and fruit samples to the University of Goettingen for analyses. The undergraduate and graduate students will be directly involved at every stage in the process and will receive training on sample collection, preparation, and analysis. In addition, with the support from the project’s technician, the team will identify potential farmers who are interested and able to participate in the farmers’ field trials. The object of this study is to compare farmers’ current practices with living mulch technology for their vegetable crops. The researchers will provide the farmers with Arachis pintoi cuttings to be cultivated in a small plot in their fields. During and at the end of the growing period, the team will conduct a farmers’ adoption study by asking them their perceptions, constraints, and benefits of this living mulch. They will also determine if farmers need a training course on living mulch management or on other skills related to vegetable production that they may lack. Finally, the PI and his group will work with their U.S. partner Dr. Stewart to support the graduate and undergraduate students with data analysis, result interpretation, and preparation of their theses.

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