Exploring the scientific evidence and economic benefits behind glyphosate-based herbicides in oil palm cultivation
Walk through any oil palm plantation in Ghana or Benin, and you'll witness a silent, ongoing battle waged just below the picturesque canopy. This isn't a conflict against insects or disease, but against relentless, fast-growing weeds that compete with the valuable oil palm for nutrients, water, and sunlight 1 .
For decades, plantation managers faced a difficult choice: deploy teams of workers for back-breaking manual weeding or find a more efficient, cost-effective solution.
The introduction of glyphosate-based herbicides like Round Up transformed this battle, offering not just effective weed control but significant economic advantages that reshaped plantation management across West Africa .
Oil palm, known scientifically as Elaeis guineensis, is a remarkably efficient source of vegetable oil, producing more oil per hectare than any other major oil crop. However, during its immature growth phase (typically the first 2-3 years after planting), the young palms are particularly vulnerable to competition from weeds 1 .
Traditional manual weeding methods require substantial labor and must be repeated frequently as weeds regrow quickly. In regions where labor availability is inconsistent or costs are rising, this approach becomes economically challenging 2 . The search for alternatives led agricultural scientists to investigate chemical solutions that could provide longer-lasting control with reduced labor requirements.
To understand how glyphosate-based herbicides like Round Up perform in real-world conditions, researchers at the Benso Oil Palm Plantation in Ghana conducted a carefully designed study on two-year-old oil palm trees 1 .
The researchers monitored these plots over several weeks, measuring weed mortality, dry weight reduction of weeds, and the vegetative growth of the oil palms themselves to assess both efficacy and safety 1 .
The results demonstrated that appropriate glyphosate doses provided effective weed control while benefiting the young oil palms:
| Treatment | Dose | 2 Weeks After Treatment | 4 Weeks After Treatment | 8 Weeks After Treatment |
|---|---|---|---|---|
| Glisat | 1.4 L/ha | Moderate control | Good control | Excellent control |
| Glisat | 2.8 L/ha | Good control | Excellent control | Excellent control |
| Ceresate | 1.5 L/ha | Good control | Excellent control | Excellent control |
Source: Adapted from Ofosu-Budu et al., 2014 1
The timing of assessment proved crucial—while differences appeared in the first two weeks, by 8 weeks after treatment, the glyphosate applications at 1.4-2.8 L/ha showed excellent control comparable to established products 1 . Researchers identified 4 weeks after application as the optimal period to observe peak weed mortality.
| Treatment | Frond Production | Frond Length | Canopy Development |
|---|---|---|---|
| Weeded (Glyphosate) | Significant increase | Notable improvement | Lush, healthy appearance |
| Unweeded Control | Reduced production | Stunted growth | Sparse, uneven development |
Source: Adapted from Ofosu-Budu et al., 2014 1
| Herbicide Solution | Composition | Function in Research | Application Considerations |
|---|---|---|---|
| Glyphosate-based herbicides (e.g., Round Up) | 480-490 g/L glyphosate | Non-selective systemic herbicide controlling both grasses and broadleaves 1 4 | Applied at 1.4-2.8 L/ha for balanced efficacy 1 |
| Glisat 480SL | 480 g/L glyphosate | Test formulation compared against established products 1 | Effective at 1.4 L/ha for grasses, higher doses (2.8 L/ha) for broadleaves 1 |
| Ceresate | Glyphosate formulation | Reference product in comparative studies 1 | Standard application at 1.5 L/ha provides benchmark performance 1 |
| Isopropylamine glyphosate | 525 g/L glyphosate | Higher concentration formulation for extended control 7 | Effective at 787.5-1,575 g/ha depending on weed species 7 |
Recent research from Southern Benin has refined our understanding of optimal dosing, showing that even lower glyphosate doses (960 g/hectare) can effectively reduce weed species richness from 36 species to just 8 surviving species, providing a potential path for reducing chemical inputs while maintaining control efficacy 2 .
The transition to glyphosate-based weed control isn't just about efficacy—it's fundamentally an economic decision for plantation managers. Research from Ghana highlights several cost-related advantages :
60-80%
Manual weeding requires approximately 20-30 person-days per hectare, creating significant and recurring labor costs. Glyphosate applications can reduce this requirement by 60-80%.
10-12 weeks
While manual weeding provides immediate but temporary relief, glyphosate offers extended protection from weed competition—typically 10-12 weeks compared to 4-6 weeks for manual methods 1 .
+15-25%
By reducing competition during critical growth phases, glyphosate applications contribute to healthier palms and potentially higher yields once the palms reach maturity 1 .
The economic calculations extend beyond simple cost comparisons. As noted in research from Benin, different glyphosate doses allow managers to tailor applications to specific weed pressures, optimizing control while managing expenses 2 . This flexibility creates opportunities for precision agriculture approaches that further enhance economic returns.
As agricultural science advances, researchers continue to refine weed management strategies. Current trends focus on:
Combining glyphosate with other control methods to prevent herbicide resistance and maintain environmental balance 2
Studies in Benin demonstrate that lower glyphosate doses (960 g/hectare) can effectively control weeds while potentially reducing environmental impact 2
The ongoing scientific evaluation of glyphosate ensures that oil palm cultivation can continue to evolve toward more sustainable, productive, and economically viable systems. As one study concluded, glyphosate applied at appropriate doses not only controls weeds effectively but "significantly improved vegetative parameters by reducing competition with weeds for nutrients and other growth resources" 1 —a benefit that ultimately extends from the plantation to the global marketplace of agricultural commodities.
The story of glyphosate in oil palm plantations demonstrates how agricultural science continuously seeks to balance multiple objectives: worker efficiency, economic viability, environmental responsibility, and crop productivity. Through careful research and responsible application, this tool has helped shape a more sustainable future for one of the world's most important oil crops.