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PARTNERSHIPS FOR ENHANCED ENGAGEMENT IN RESEARCH (PEER)
Cycle 7 (2018 Deadline)


Increasing the adoption of nutrient management innovations by Cambodian vegetable farmers

PI: Leangsrun Chea (cleangsrun@rua.edu.kh), 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 - March 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)
Final Summary of Project Activities

This project, which ran from February 2019 through March 2021, was aimed at assessing nutrient innovation practices and increasing their adoption by vegetable farmers. In the first year, the major activities included recruitment of students and supporting staff, field visits to previous USAID-funded project sites, baseline surveys, and initiation of an on-station experiment. A technician was recruited to support the overall project activities, mainly the baseline survey, on-station trials, farmers’ field trials, and farmers’ adoption study. She also helped guide the work of the undergraduate and graduate students on the project. One Master’s and three undergraduate students (two of them female) worked on the project, receiving training and hands-on experience in field survey techniques, experimental design, data collection, and data management. In the second quarter of Year 1, the U.S. partner Dr. Zach Stewart had the opportunity to visit Cambodia, which allowed him and the PI Mr. Leangsrun Chea to meet in person, discuss the activity plan, and visit USAID-funded project sites. Specifically, the two 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 provinces. Through this field visit, they identified living mulch Arachis pintoi as a promising technology that could benefit farmers in terms of weed and nutrient management in vegetable crops. The activities corresponding to the proposed objective are described below:

Objective 1: Conduct an ex-ante survey to gain information on farmers’ current practices and concerns regarding the use of decision support innovations for vegetable nutrient management. The project team conducted a baseline survey to learn about farmers’ current vegetable nutrient management practices and solicit their perceptions on living mulch integration in their vegetable crop production processes. The researchers drafted a questionnaire, including questions on farmers’ annual vegetable crop patterns, nutrient inputs, harvest amounts, knowledge of soil quality evaluation and improvement, and understanding of living mulch Arachis pintoi. They pre-tested the questionnaire in Siem Reap Province, interviewing 10 farmers to assess the suitability of the questions. Furthermore, the team had a discussion with local extension agents to learn about the current status of vegetable farmers and identify an appropriate location for the farmer interviews. After the pre-test was complete, the PI and his colleagues interviewed 155 households in four districts in Siem Reap Province. These four districts are the main vegetable supply sources for the province and even supply vegetables to nearby provinces. The results from this baseline survey revealed that most of the farmers depended almost entirely on inorganic fertilizer for growing vegetable crops. Weed management was among the constraints that consume substantial labor and budget resources, and there was a clear need to improve management practices, i.e. living mulch application, to optimize nutrient use and minimize costs and labor associated with weed management. Furthermore, about 30% of the farmers were aware of living mulch; however, they lacked the skills to integrate it into their vegetable production. An undergraduate student participated on the survey team and applied the result in thesis research. It was not possible to collect soil samples as planned during Year 1, but the PI and U.S. partner agreed that the samples would be taken in conjunction with the farmers’ field trials in Year 2 of the project.

Objective 2: Implement and evaluate on-station and on-farm nutrient management experimentation comparing farmers’ current nutrient management strategies with the use of nutrient recommendation decision support innovations. On-station experiments were conducted at the Technology Park (TP) of the Center of Excellence on Sustainable Agricultural Intensification and Nutrition (CE SAIN) at the Royal University of Agriculture (RUA). Work on this project objective involved one master’s and one bachelor’s degree student. The objective of this trial was to assess the interactive effect of living mulch and phosphorus fertilization levels on the soil quality and nutritional quality of chili pepper. The project team monitored the trial over three consecutive crop cycles. Their goal was also to showcase the nutrient management and living mulch technology to park visitors. The researchers collected data on crop growth, yield, nutritional quality, and soil quality, and they analyzed plant biomass and soil quality characteristics the RUA soil laboratory. Furthermore, in collaboration with the Division of Plant Product Quality at the University of Göttingen, Germany, chili pepper leaf and fruit samples were analyzed for mineral concentration.

In order to implement on-farm nutrient management trials, the PEER team identified 31 farmers from three out of four districts where interviews were conducted. The farmers received living mulch cuttings and training on how to how to place and cultivate them. One bachelor’s student and the technician were involved in supporting and following up with the farmers on the trials. Due to COVID-related travel restrictions, they could not visit the trial sites frequently; therefore, a local extension agent was engaged to coordinate with the farmers. In addition, the technician followed up with farmers and extension agent by phone.

Objective 3: Provide need-based training for farmers on improved nutrient management practices for vegetable crops.
Although formal training programs were not conducted, regular need-based support was provided to the individual farmers who participated in the on-farm trials. The PI and his colleagues provided technical advice to farmers based on the specific problems that they encountered either during the field trials or previously. Furthermore, the local extension agent who helped to support the farmers’ field trials also received technical suggestions regarding the living mulch and vegetable production practices, which he was then able to disseminate to other farmers. In addition, in collaboration with CE SAIN, the PEER team organized a lecture series for RUA undergraduate students on the importance of phosphorus fertilization in crop production.

Objective 4: Gain feedback about the acceptability and profitability of the nutrient management decision support tool through an ex-post survey and focus group discussions with farmers and local extension agents. The 31 farmers who participated in field trials were comprehensively interviewed in order to gain further information on their vegetable production practices in addition to the baseline survey and to assess how their practices influence the living mulch adoptions in their vegetable plots. The PI conducted this adoption survey in collaboration with a researcher at the Department of Agricultural Economics and Rural Development of the University of Göttingen, who helped in drafting the questionnaire and analyzing the data. Team members also collected soil samples from each participating farmer’s field to compare soil organic carbon and other soil quality characteristics in the living mulch and non-living mulch plots. The results of the adoption study and soil quality analyses were evaluated and used by an undergraduate student for her thesis. A comprehensive evaluation of the results is being conducted and a manuscript will be developed for publication in a peer-reviewed journal.

Objective 5: Develop technical leaflets on nutrient management recommendations based on farmer’s available resources and inputs that serve as decision support tools to support knowledge dissemination and adoption. Based on their survey, on-station, and on-field trials, the PI and his group developed a technical leaflet on the application of living mulches in vegetable production as a support tool for farmers to improve their vegetable production practices. They will work with CE SAIN to publish the leaflet and disseminate it to farmers and extension agents.

Overall on the project, seven undergraduate and graduate students were trained on skills involving in conducting the household surveys, and they also took part in the baseline survey. Four undergraduate and graduate students were trained on field experimental design, monitoring, data collection, and data arrangement. The skills that the students gained during the training will benefit them in their future careers in the community. The 31 farmers involved in the field trials received need-based training on living mulch establishment and integration in vegetable production. Furthermore, the adoption of nutrient management innovation by farmers will help to improve their vegetable production, reduce input costs for weed management and mineral fertilizer purchases, and ultimately improve household income generation. The innovative living mulch also minimizes negative impacts on the environment caused by improper fertilizer applications.

Based on the results from this project, the team observed the impact of living mulch in improving soil nutrient availability and vegetable yield. They feel this technology has the potential to be scaled up, but it requires a larger framework for an adoption study to assess its suitability across regions and vegetable species. Furthermore, the team’s on-station trials provided the first report on the impact of agronomic practices on the nutritional quality of chili pepper, which provides the basis for further study to improve the nutritional quality of additional vegetables in Cambodia. The PI reports that he and his colleagues plan to develop follow-on proposals to build upon their PEER project findings.


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