Chief of Agronomy (Pailin PDAFF) Sophanara Phan, Senior Project Researcher Panhaleak Chay, and Dr Van Touch reflect on some of the impacts they are seeing as a result of practical training on cassava Good Agricultural Practices (GAP).
Cassava is an important cash crop for upland smallholders in Northwest Cambodia, particularly in Battambang Province and Pailin Province. However, production systems are under pressure.
Farmers face rising temperatures, erratic rainfall, droughts and localised flooding. These conditions worsen long-standing problems of soil erosion and declining soil fertility on rainfed, sloping land with limited irrigation.
Pests, diseases and weeds also reduce yields. Mealybugs, red spider mites, cassava mosaic disease (CMD), cassava witches’ broom (CWB) and root rot are now common. Many farmers struggle to identify these problems, choose safe and effective control methods, or access healthy planting material.
Production practices also contribute to low yields. Many farmers do not apply base fertiliser, relying instead on short-acting foliar products. Herbicides are often used at the wrong time, and few farmers keep production records or develop basic farm budgets.
“I did not understand the techniques for selecting cassava varieties… or the methods for controlling pests and diseases. I did not know when to apply chemical fertiliser either.”
Between May and June 2025, three complementary activities were led by Partners for Rural Development in collaboration with the Pailin Provincial Department of Agriculture, Forestry and Fisheries. Cassava specialists Daraoudom Leng and Tin Maung Aye provided technical facilitation.
Village workshops, group analysis and field visits build practical skills
An eight-day GAP training program led by Daraoudom Leng engaged 60 farmers across four villages.
Training combined group problem analysis, classroom sessions, videos and field visits. Farmers completed a nine-lesson module covering cassava variety selection, stem and soil preparation, fertiliser management, pest, disease and weed control, harvesting, stem production, and basic production planning.
The content addressed five farmer-identified constraints: premature harvesting of Rayong 9, limited base fertiliser use, poorly timed weed control, reuse of diseased stems, and absence of production planning.
Through exercises and field observation, farmers learnt to distinguish varieties such as Rayong 11 and Huay Bong 60, understand N-P-K roles, identify pests and diseases, and select appropriate herbicides and timings. They also practised simple budgeting tools to track inputs and outputs. Each village received CMD- and CWB-resistant planting material for testing.
Classroom sessions and farm visits link training to real field conditions
A second eight-day training program led by Tin Maung Aye and Sophanara Phan reached 56 farmers (29 women and 27 men) in four more villages.
Training combined classroom sessions with guided farm visits. Day 1 introduced climate change impacts, variety selection, land preparation and vertical planting, balanced fertiliser use, and integrated pest, disease and weed management. Day 2 focused on visits to farmers’ plots, where participants diagnosed real crop problems and discussed practical responses with trainers.
A practical GAP manual reinforces training
To reinforce the training and reach more farmers, a Good Agricultural Practices manual for cassava was developed and distributed to an additional 124 farmers.
The manual targets upland smallholders where cassava yields often remain well below the potential of about 50 tonnes per hectare.
It provides practical guidance on:
- selecting high-yielding and CMD-resistant varieties and healthy stem cuttings
- conservation-oriented land preparation, vertical planting and erosion control
- balanced fertiliser use using the 4R nutrient management approach
- integrated management of major diseases, insect pests and weeds
- cassava–maize and cassava-legume intercropping and rotations.
Designed for farmers and extension officers, the manual also highlights opportunities to train rural youth as climate-smart cassava advisers.
What changed for farmers
Increased knowledge and behaviour change
Farmers reported much stronger practical understanding of:
- land preparation to avoid waterlogging and match ploughing and ridging to soil type
- when and how to plant to make best use of rainfall
- how to select, cut and store healthy, disease‑free stems
- how to identify major pests and diseases and link symptoms to underlying causes.
Across villages, farmers began selecting disease‑free planting material and discarding CMD‑ and CWB‑affected stakes, applying fertiliser at recommended rates and timings (often with organic inputs), using more appropriate herbicides at the right growth stages, and asking tractor drivers to prepare land to reduce waterlogging.
“I used high‑yield cassava variety Rayong 9, applied proper planting techniques, improved pest and disease control, and applied chemical fertiliser. On my 0.8‑hectare farm, yield increased from 10 to 20 tonnes and I got more profit.”
Increased yield, reduced losses and better planning
Many farmers observed higher yields and better returns; in some cases, yields doubled on the same area after changes to variety choice, planting, fertiliser and pest management. Healthier planting material, better land and water management, and more targeted pesticide use reduced CMD, CWB, root rot and insect damage, with regular field inspection helping farmers act earlier.
Training on production planning introduced basic financial management. Farmers learnt to list inputs and costs, estimate yields and income, and understand “money in and money out” across the crop cycle. This increased confidence to invest in improved practices and judge profitability, not just yield.
Psychological change
The training also shifted attitudes. Farmers reported greater self‑confidence, less fear of crop failure and more hope of achieving higher yields under changing climatic conditions. They valued that content responded directly to their own stated problems and that role plays, discussions and field visits made learning tangible and relevant.
Farmers reported that hands-on learning in their own fields helped them understand and apply the practices effectively.
Remaining barriers and next steps
Despite these improvements, farmers highlighted ongoing constraints. The most common is limited capital to purchase fertiliser and other inputs at recommended levels.
One farmer commented: “I wanted to follow the fertiliser recommendations, but I did not have enough money to buy chemical fertiliser.”
These challenges sit within a wider systemic context. Many cassava farmers operate amid entrenched rural inequality, limited access to land, credit and infrastructure, and dependence on a single cash crop sold into volatile markets. Limited liquidity and indebtedness mean that even when farmers understand benefits, they may not be able to finance inputs or absorb short‑term risk.
Climate uncertainty, repeated droughts, floods and shifting seasons interact with structural, demographic and mobility processes such as youth migration, ageing farmers and reliance on off‑farm work.
Training cannot remove all constraints, but it helps farmers make better‑informed decisions, avoid costly mistakes and see where targeted support (credit, insurance, market information, extension) may be needed.
Farmers and experts proposed practical next steps. Daraoudom Leng recommends establishing village demonstration plots, where one farmer applies recommended fertiliser rates and GAP practices so neighbours can compare yields and income.
Farmers also suggested short courses on producing homemade fertiliser and compost to reduce input costs.
“To improve my cassava farming, I suggest training on how to produce compost fertiliser to reduce production costs and save money on fertiliser purchases.”
The training approach, combining workshops, field visits and demonstrations, could also be used to train commune agricultural officers and research assistants in cassava agronomy. Scaling this farmer-centred, field-based extension model to more villages will support more resilient and profitable cassava production in Northwest Cambodia.
