Evaluation of a package on mechanized dry direct seeding with laser land leveling in Cambodia December 2025 | Page 1 of 13 CGIAR Sustainable Farming Science Program Report | Mechanized DSR with low input Contents | Page 2 of 13 Contents 1. Introduction 3 2. Methodology 3 2.1 Trial site .................................................................................................... 3 2.2 Field laser land leveling............................................................................ 3 2.3 Participatory trials .................................................................................... 4 2.4 Trial design and layout ............................................................................. 4 3. Findings from mDSR with laser land leveling package 6 3.1 Yield performance .................................................................................... 6 3.2 Plant height distribution and uniformity .................................................... 6 3.3 Economic efficiency ................................................................................. 6 3.4 Nutrient efficiency..................................................................................... 7 3.5 Water cost efficiency (WCE) .................................................................... 7 4. Conclusion 8 Appendix 1: Fertilizer management 9 Appendix 2: Weed management 9 Appendix 3: Water management 10 Contents | Page 3 of 13 1. Introduction The Excellence in Agronomy Initiative, and thereafter the Sustainable Farming Science Program, has supported the development of mechanized direct seeded rice (mDSR) in Cambodia. Although there have been prior evaluations for wet direct seeding, which resulted in positive outcomes, the performance of mDSR in dry direct seeding was not opimal. One of the key constraints was the limitations of land leveling practices. In 2025, an evaluation of the performance of mDSR agronomic package bundled with laser land leveling was implemented. The innovation package integrates dry mechanized direct seeding (dry-mDSR), laser land leveling (LLL) and improved agronomic practices (IAP), aimed at sustainably increasing yield and profitability. Additionally, this integrated approach enhances environmental sustainability through improved water use efficiency, reduced input costs, and minimized environmental impact, contributing to more resilient and eco-friendly rice production systems. The package implemented specifically emphasized lower seed rates, early maturing varieties, mechanized planting, and enhanced water, fertilizer, weed, pest, and disease management. These practices were trialed against farmers’ traditional methods, which relied on higher seed rates, manual planting, conventional land leveling, and less targeted management, often involving routine chemical applications and less efficient resource use. The comparison reflects the hypothesis that the CSA innovation package of laser land leveling, mechanized dry direct seeding and improved agronomic practices significantly enhances rice yield, profitability, and environmental sustainability in the Tonle Sap region. The objective is to evaluate the impact of a Climate Smart Agriculture (CSA) innovation package comprising Mechanized Dry Direct Seeded Rice (mDSR), laser land leveling, and improved agronomic practices (mDSR+LLL) on rice production in the Tonle Sap Region in Cambodia. 2. Methodology 2.1 Trial site The first season of participatory field trials were established during early wet season 2025 cropping season. The trial was conducted in Raing Kesei irrigation scheme located in Sanke district, Battambang (Table 1 has geolocations of the sites). Mainly double rice cropping system in wet season is prevalent in the area. Some farmers can have an additional rice cultivation crop in dry season if there is enough water from main Sanke river source. 2.2 Field laser land leveling The trial fields selected had no history of leveling activities in the past two years to ensure unbiased results. A laser land leveling service provider was contacted, and the purpose of CGIAR Sustainable Farming Science Program Report | Mechanized DSR with low input Contents | Page 4 of 13 leveling was clearly communicated. Prior to operating the laser leveling equipment, the fields were inspected to assess their current condition and time needed for the leveling activity. Survey data were collected before leveling to establish baseline field conditions. The laser leveling process was then carried out. After the leveling was completed, a post-leveling survey was conducted to collect the survey data again. This post-leveling survey was used to pair with the pre-leveling survey to evaluate the performance of the laser leveling process, ensuring the field leveling accuracy met the target requirement of ± 2-5 cm. 2.3 Participatory trials Five selected sites are included in the trials. These are managed by farmers who implement a treatment plot for mDSR with LLL, along with a control plot. The selection was based on several factors like rice ecosystem, suitability of field location, availability of seeding, and laser leveling services, relationship with neighbors, motivation and willingness to participate, openness to test new climate smart practices, and influence on other neighbor farmers across the community. The farmers participated with informed consent. Table 1: List of farmerd and trial sites of mDSR with LLL and IAP No Farmer name District Province Geo location 1 Thouern Thorn Sangke Battambang 12.931389, 103.280194 2 Nuon Bonat Sangke Battambang 12.920444, 103.272583 3 Soy Sophal Sangke Battambang 12.911333, 103.268556 4 Suon Leng Sangke Battambang 12.908667, 103.263056 5 Sar Sopheak Sangke Battambang 12.907861, 103.284389 2.4 Trial design and layout The study employed a randomized complete block design (RCBD) with two treatments and five replications. Treatment T1 consisted of dry-mechanized seeding rice (Dry-mDSR) combined with laser land leveling (LLL) and improved agronomic practices (IAP), while Treatment To represented farmers’ practice (FP) and served as the control (Table 2). The trials were conducted in the rice growing area laid within the well-functioning irrigation schemes, where five farmers acted as replications. Each replication contained a paired comparison of the two treatments (fig. 1), ensuring that both were implemented under homogenous field conditions. Stratified random sampling was used to allocate treatments within replication, accounting for site heterogeneity and achieving balanced representation across replicates. Table 2: Treatments with description No. Treatment Description 1 T1: Dry-mDSR with LLL and IAP Combination of mechanized dry direct seeding (Dry- mDSR), laser land leveling (LLL), and improved agronomic practices (IAP) 2 T0: Farmer’s Practices (FP) Farmer’s Practices (FP): Broadcasting method, farmer’s practice for land preparation plus tradition leveling and crop management (>200 kg/ha of seed Contents | Page 5 of 13 rate, use saved seeds, no pre-emergence herbicide, FP fertilizer application, etc.) Table 3: Summary of improved agronomic practice with mDSR + LLL Items T1 (Dry-mDSR+LLL+IAP system) Farmers’ practice 1. Seed rate 100 kg ha-1 >200 kg ha-1 2. Variety Sen Kra krob 01 (early variety) Sen Kra krob 01 (early variety) 3. Crop establishment Dry mechanized row seeding Dry hand broadcasting 4. Land leveling Laser land leveling Conventional land leveling 5. Fertilizer management Follow recommended fertilizer application rates and timing for early -maturing varieties (Appendix 1) Farmer’s practices for fertilizer applications (about 300kg/ha) 6. Weed management Follow recommended fertilizer application rates and timing for early -maturing varieties (Appendix 2) Only post emergence herbicide application 7. Pests and diseases management - Apply IPM and no insecticide application within 40days of seeding - A maximum of 1 insecticide application after 40DAS - Apply up to 2 applications of available fungicide options of fungicides before the flowering stage if it is significantly infected. Farmer’s practices for pest and disease management (at least 3-4 application time per crop 8. Water management after seeding Recommended water saving practices, at least one single drainage (Appendix 3) Continuous flooding Figure 1: Sample layout for a farmer replication occupied two treatments, three small square inside are the crop cut sampling points, with 5 square meter size CGIAR Sustainable Farming Science Program Report | Mechanized DSR with low input Contents | Page 6 of 13 3. Findings from mDSR with laser land leveling package 3.1 Yield performance There was no statistically significant difference in grain yield between the two treatments at the current replication level (p = 0.3771, n=5). Although this climate-smart package shows a higher numerical yield (about 5%), the lack of significance suggests the yields are statistically equivalent under the tested conditions (Fig. 2). Note: CV: coefficient of variation, n=5; not significant: p-value > 0.05; statistically significant: p-value ≤ 0.05 Figure 2: Yield performance (left); Plant height uniformity (right) 3.2 Plant height distribution and uniformity Plant height distribution and uniformity serve as key indicators to assess the effectiveness of field leveling by comparing with the control plot. The plant height distributions under T0 and T1 are statistically similar (figure 2). The mean plant height (p = 0.8393) and variance (p = 0.2395) show no significant differences, indicating comparable overall stature and spread. The coefficient of variation (CV) is slightly lower with T1 (5.6% vs. 6.3% in T0), suggesting a potential trend toward greater uniformity, possibly due to improved micro-field level topography from laser leveling, more consistent seeding with mechanized dry direct seeding, and much better field leveling at the selected farmer practice plots. Although the coefficient of variation was slightly lower under T1, both mean and variance differences were statistically non- significant (p > 0.05). Therefore, the observed improvement in uniformity should be treated as an indicative trend rather than a confirmed effect. Larger sample sizes or additional replications (especially the field topography of the farmer practice plot) are needed to check out whether T1 consistently enhances plant height uniformity. 3.3 Economic efficiency Economic efficiency reflects production cost and profitability-cost ratio, serving as strong indicators for comparing the relative performance and competitiveness of this CSA innovation package and farmer practices. The comparison showed T1 reduces total costs by about 11.5% compared to farmers’ practice - T0 (p = 0.295). Although there is potential cost savings, the difference is not significant. Additionally, PCR increased in T1 by about 25.4%. This is not Contents | Page 7 of 13 statistically varied compared to FP (p = 0.740), but aligned with improved economic efficiency under the current trial conditions (Fig. 3). Note: n=5; not statistically significant: p-value > 0.05; statistically significant: p-value ≤ 0.05; n=5 Figure 3: Comparison of production cost and profitability between T0 and T1 Overall, it shows comparable yield, with lower costs, and higher PCR, with non-significant but favorable trends that suggest mechanized dry direct seeding combined with laser land leveling could potentially offset expenses and improve economic returns. 3.4 Nutrient efficiency The comparisons between treatment demonstrated that T1 significantly enhanced phosphorus partial factor productivity (221.7 vs 118.5 kg grain kg⁻¹ P; p=0.0071). Nitrogen PFP showed a modest increase (81.7 vs 70.4 kg grain kg⁻¹ N; +16.1%; p=0.422), while potassium PFP was lower (207.4 vs 306.5 kg grain kg⁻¹ K; −32.3%; p=0.233). These results highlight a strong P efficiency benefit from the package, with potential to optimize N and K management for broader efficiency gains at this CSA package. Table 4: Table 4: Nutrient Partial Factor Productivity (PFP) for Nitrogen, Phosphorus, and Potassium Variable Mean of T0 Mean of T1 t-value p-value % change vs FP N-PFP (kg grain/kg N) 70.39 81.691 −0.894 0.4633 16.10% P-PFP (kg grain/kg P) 118.460 221.688 −6.136 0.0071 114.70% K-PFP (kg grain/kg K) 306.456 207.352 1.404 0.2261 −32.3% Note: n=5; not statistically significant: p-value > 0.05; statistically significant: p-value ≤ 0.05; n=5 3.5 Water cost efficiency (WCE) With the challenges of volume water collection from the trial plots, water cost efficiency (WCE) is a priority indicator to select for reflection on CSA efficiency within the aspect of water efficiency improving by the practices of mechanized direct seeding with laser land leveling. CGIAR Sustainable Farming Science Program Report | Mechanized DSR with low input Contents | Page 8 of 13 Water cost efficiency, which is the cost in USD of watering to produce one kilogram of grain (lower values mean more efficiency), was studied in five paired treatments. On average, the package costs about 18% more per kg than the control treatment. However, this difference was not statistically significant (t = -0.441; p = 0.671). Both treatments showed big variation in costs between each farmer (CV range from 78% and 90%). Table 5: Water cost efficiency at T0 versus T1 Treatment Mean (kg/USD) t-value p-value % change CV (%) T0 535.04 −0.441 0.671 - 90.54 T1 677.14 - - +26.56% 78.80 Note: CV: coefficient of variation; n=5; not statistically significant: p-value > 0.05; statistically significant: p-value ≤ 0.05; n=5 4. Conclusion This evaluation of the integration of mechanized dry DSR and Laser Land Leveling indicates that it has potential for sustainable rice production. While grain yield showed no statistically significant difference between treatments, a positive trend of higher yield and improved uniformity was observed. Additionally, the package contributed to reductions in production costs and enhanced economic efficiency, with phosphorus (P) use efficiency significantly improved and potential resource optimization benefits evidence, while nitrogen (N) and potassium (K) had potential to be increased to contribute more nutrient use efficiency for the system. Although water cost efficiency did not differ significantly, the overall findings suggest that integrating mechanized dry direct seeding with laser land leveling can improve resource use, reduce costs, and support more sustainable rice farming practices, which help the farmers in Tonle Sap region to increase production efficiency with resilience to climate. Further repetition of the trials in the consecutive seasons with larger sample sizes; especially increasing the replication number of farmer practice; and checking out the field level condition at the farmer practice plots is recommended to validate these findings and optimize the package's performance across diverse conditions. Contents | Page 9 of 13 Appendix 1: Fertilizer management The following are the recommended fertilizer application rates and timing for early- and mid- maturing varieties: Total applied fertilizers: Early variety: N=78, P2O5=29, K20=30 Medium variety: N=58, P₂O₅=24, K₂O=30 Application rate Variety type Total Urea DAP KCl Basal 1st top-dress Urea 2nd top-dress Urea (kg ha-1) (kg ha-1) (kg ha-1) (10-15 DAS) for ear. Var. (20-30 DAS) For Mid & late Var. (PI) Early variety 146 61 50 Urea:46 DAP: 61 KCl: 25 Urea: 50 DAP: 0 KCl: 0 Urea: 50 DAP: 0 KCl: 25 Medium Variety 107 50 50 Urea: 37 DAP: 50 KCl: 25 Urea: 35 DAP: 0 KCl: 0 Urea: 35 DAP: 0 KCl: 25 Source: DOI: https://doi.org/10.1017/S0014479719000346 for early variety. Appendix 2: Weed management Application of pre- and post-emergence herbicide application guidelines may decide and apply as bellow (1) pre-emergence herbicide application Pretilachlor + safener 300 g ai ha-1 or 1000 ml ha-1 or as per recommended rate in Cambodia (label rate), apply at 1-3 days after direct seeding when water in the field is 1-2 cm (Wet wet- direct seeding). Butachlor 60% with safener 1l ha-1 or as per recommended rate in Cambodia (label rate), apply at 1-3 days after the soil is saturated (dry-direct seeding). (2) post-emergence herbicide application Post-emergence herbicide will be decided after field inspection and identification of the weeds; at 10-15 days after seeding, Xevelo was recommended as post emergence herbicide Based on weed population, apply it as per recommended rate in Cambodia (label rate) (e.g., Xevelo 120 EC (Florpyrauxifen-benzyle 20g l-1 + Cyhalofop 100 g l-1) apply 1200 ml ha- 1), and then, followed by hand-weeding at 30-35 DAS as needed. The field should be drained before spraying post-emergence herbicide and then water can be introduced again after 24 hours. Make sure that there is no strong wind during the herbicide application. The application should be timed to avoid rain at least 4-6 hours after spraying. CGIAR Sustainable Farming Science Program Report | Mechanized DSR with low input Contents | Page 10 of 13 And, if it is available, it is recommended to use the multiple (rather than single) nozzle boom fitted with flat fan nozzles during spray. If multiple nozzle booms are not available, then use a single nozzle boom fitted with cut/flood jet type nozzle. Avoid using cone type nozzles for herbicide spray. If needed there could be a follow-up hand weeding at 30-35 DAS. Optional: In case there is a severe problem with golden apple snail, keep fields drained as much as possible (keep water below 2cm) during the vulnerable stages of the rice plant (before rice is 30 days old). Appendix 3: Water management For dry DSR, it needs an assured water supply for the first 2 weeks after seeding for good establishment, applying light irrigations as needed - do not allow water to pond for more than a few hours; drain the water off the field if necessary. Alternative Wetting and Drying (AWD) and mid-season drainage (MSD) are recommended, but not required, a good way for water management in mDSR (See appendix B for installment and reading), allowing the soil surface to dry for a few days or more, depending on soil types, between irrigations. However, if the soil becomes too dry too often, the rice crop will suffer and there will be a loss of yield. Therefore, irrigation needs to be managed carefully. Typically, water is irrigated to the fields when the water table reaches approximately 15 cm below the soil surface except for 1–2 weeks after planting and for heading and flowering stages. Therefore, it is recommended four times to keep drainage water in the field between vegetative to early reproductive phase, and after flowering stage if all field conditions are allowed. If not, it recommended at least once of keeping the field drainage. However, if the soil becomes too dry too often, the rice crop will suffer and there will be a loss of yield. During the active tillering phase, and the heading to the grain-filling stage, the topsoil (0–15 cm) should be kept close to saturation, with irrigation applied as needed. At other stages the topsoil can be allowed to become drier, but never to the degree that the leaves show signs of rolling (no longer flat) in the early morning. Citation: Contents | Page 11 of 13 Keo, S., Chuong, T., Then, R., Mabilangan, A., Flor, R. Saito, K. 2026. Evaluation of a package on mechanized dry direct seeding with laser land leveling in Cambodia. Acknowledgements The work is supported by the Promoting Climate Resilient Landscapes in the Tonle Sap, funded by the Global Environment Facility. We would like to thank all funders who supported this research through their contributions to the CGIAR Trust Fund: https://www.cgiar.org/funders/ About CGIAR Sustainable Science Program Report This research was conducted as part of the CGIAR Sustainable Farming Science Program. This research is being implemented by CGIAR researchers from (insert names of CGIAR Centers involved) in close partnership with (list all partners involved). 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CGIAR Sustainable Farming Science Program Report | Mechanized DSR with low input Contents | Page 12 of 13 About CGIAR Sustainable Farming Science Program The CGIAR Sustainable Farming Science Program will address key challenges in agrifood systems by fostering efficient production of nutritious foods and safeguarding the environment to create fair employment opportunities, as we simultaneously tackle climate change, soil degradation, pests, diseases, and desertification. Contents | Page 13 of 13 With partners