How to choose the right cover crop for your Malaysian estate
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One size does not fit all
Choosing the right cover crop species is one of the most important decisions in any ground cover programme. The wrong species for your conditions will establish poorly, fail to deliver the expected benefits and may need to be replaced, wasting time and money. The right species, matched to your terrain, tree crop and management priorities, keeps delivering value for years.
This guide walks through the key decision factors and which species fits which situation.
Decision factor 1: establishment speed vs. long-term performance
The first question is whether you need fast ground cover or can manage a longer establishment period for better long-term results.
Faster establishment
If your priority is rapid ground cover (for example, during replanting when weed pressure is high and bare soil is exposed to erosion), Calopogonium mucunoides (CM) and Pueraria javanica (PJ) are the usual choices.
CM is a fast starter. PROSEA 11 notes that it covers the soil 3 to 6 months after sowing (sooner on newly cleared fertile land) and forms a dense sward at 4 to 5 months (Chen Chin Peng and Aminah, 1997). It fixes nitrogen and is relatively tolerant of acidic soils. CM is often used as a pioneer species in mixed plantings, providing quick cover while slower species establish, and is usually the first to be shaded out.
PJ offers a balance of establishment speed and long-term performance. It draws most of its nitrogen from the air: in one northeast Thailand trial under young rubber it accumulated up to 250 kg N/ha per year in above-ground biomass, 85 to 93% of it from fixation (Clermont-Dauphin et al., 2016). PJ is one of the most widely used cover crops in Malaysian oil palm plantations because it performs consistently across a wide range of conditions.
Longer establishment, strong long-term cover
If you can manage weed control during a longer establishment window, Mucuna bracteata (MB) gives dense, long-lasting cover. How fast it covers depends on planting density and soil. In a UPM trial on mineral soil, MB planted at 680 seedlings/ha (1.5 m spacing) reached about 100% ground cover at 6 months (Samedani et al., 2015). On deep peat at Teluk Intan, MB at 320 seedlings/ha covered 31% of the ground at 6 months, 58% at 12, 75% at 18 and 78% at 24 months (MPOB TT 501).
Once established, MB forms a dense canopy and a heavy litter layer, and fixes much of its nitrogen from the air: 67 to 84% in a 15N study under three-year-old oil palm on Jawa Series soil in Malaysia (Cheah, Zaharah and Aminuddin, 2010), with no routine annual rate asserted. For weed control, the UPM trial found that the cover crop treatments together cut weed dry weight by 97.3 to 99.9% and weed density by 94.77 to 99.73% compared with unweeded plots, 9 to 24 months after planting (Samedani et al., 2015).
MB suits new plantings or replanting programmes where you can plan the establishment timeline in advance. It is raised as nursery seedlings and quoted per hectare in seedlings, not kilograms.
Decision factor 2: light conditions
The amount of light reaching the ground between tree rows varies with tree species, age and planting density.
Full sun to light shade
In young plantings, before the canopy closes, light conditions suit all four species. This is the best window for establishing MB or PJ, which grow best in higher light.
Moderate to heavy shade
In mature oil palm or rubber plantations, where the canopy cuts ground-level light substantially, Centrosema pubescens (CP) is usually the better choice. CP is among the more shade-tolerant species in this group and keeps growing and fixing nitrogen under conditions where the others decline.
If you have a mix of young and mature areas, consider PJ or MB for young blocks and CP for mature blocks.
Decision factor 3: terrain and slope
Sloping terrain needs cover crops with strong root systems and dense ground cover for erosion control.
PJ and MB both perform well on slopes. PJ’s trailing habit and relatively quick establishment give good early erosion protection. MB’s dense canopy and thick litter layer give strong long-term protection, which makes it a common choice on steep slopes.
On flat or gently sloping terrain, any of the species can work. On flat ground, choose on other priorities such as establishment speed, nitrogen fixation or shade tolerance.
Decision factor 4: soil conditions
Soil pH and drainage influence cover crop performance. These legumes are widely grown on the acidic soils common in Malaysia, and CM is noted for tolerating strongly acidic sites, such as some peat and laterite areas.
On poorly drained or waterlogged sites, PJ tends to perform better than the other species. MB prefers well-drained soils and may struggle in persistently wet conditions.
Decision factor 5: budget and seed cost
Seed costs vary by species and are set on the quotation for your site. Weigh seed cost against the total programme cost, including the weeding needed while the cover establishes.
Recommended species by scenario
For new oil palm planting on flat to moderate slopes, a PJ and MB combination gives early cover with strong long-term performance. For replanting with high existing weed pressure, use CM for quick establishment, moving to MB or PJ in the second year. For mature oil palm with heavy shade, use CP as the main species, possibly with PJ in lighter areas. For rubber plantations, use PJ as the main species with CP in heavily shaded areas. For steep terrain needing erosion control, use MB as the main species with PJ for early cover while MB establishes.
The mixed-species approach
Many experienced estate managers do not plant a single species. Instead, they combine two or three species to use the strengths of each. A common approach combines CM (fast initial cover) with MB (long-term cover), so CM provides early weed suppression and erosion control while MB builds up to take over as the dominant ground cover.
Contact Chemiseed to discuss which species or combination suits your estate. Our agronomy team can help you plan a cover crop programme for your terrain, tree crop and management goals.
Browse our cover crop seed range for species and availability and request a quote, or visit our FAQ page for technical specifications.
Sources
- Cheah, S.S., Zaharah, A.R. & Aminuddin, H. (2010). Biological nitrogen fixation by Mucuna bracteata under oil palm field environments. Oil Palm Bulletin 60: 22-27. Malaysian Palm Oil Board.
- Chen Chin Peng & Aminah, A. (1997). Calopogonium mucunoides. In: Faridah Hanum, I. & van der Maesen, L.J.G. (eds), Plant Resources of South-East Asia No. 11: Auxiliary plants. Backhuys, Leiden.
- Clermont-Dauphin, C., Suvannang, N., Pongwichian, P., Cheylan, V., Hammecker, C. & Harmand, J.-M. (2016). Dinitrogen fixation by the legume cover crop Pueraria phaseoloides and transfer of fixed N to Hevea brasiliensis: impact on tree growth and vulnerability to drought. Agriculture, Ecosystems & Environment 217: 79-88. https://doi.org/10.1016/j.agee.2015.11.002
- Hasnol Othman, Farawahida Mohamad Darus & Zulkifli Hashim (2012). Best management practices for oil palm cultivation on peat: Mucuna bracteata as ground cover crop. MPOB TT No. 501. Malaysian Palm Oil Board.
- Samedani, B., Juraimi, A.S., Rafii, M.Y., Sheikh Awadz, S., Anwar, M. & Anuar, A.R. (2015). Effect of cover crops on weed suppression in oil palm plantation. International Journal of Agriculture and Biology 17(2): 251-260.
