Best cover crop for oil palm: species selection guide by growth stage

Immature oil palm, mineral soil (years 0 to 3)

Recommended: Mucuna bracteata (MB)

In one 15N isotope-dilution study under three-year-old oil palm on Jawa Series soil in Malaysia, MB derived 67 to 84% of its nitrogen from the atmosphere (Cheah, Zaharah and Aminuddin 2010, MPOB Oil Palm Bulletin 60). Documented to support soil cover, weed suppression, and nutrient recycling in young immature oil palm, and it may help reduce rhinoceros-beetle breeding sites. On 0 to 25% slopes under three-year-old oil palm in Riau, Indonesia, plots with MB had better soil moisture, infiltration, permeability, and organic matter, and less runoff and erosion, than plots without it (Wawan, Dini and Hapsoh 2019).

Management note: MB is vigorous and can smother young palms. Active circle maintenance is required, this species is not maintenance-free.

Immature oil palm, peat soil

Recommended: Mucuna bracteata (MB)

MPOB recognizes MB ground cover as part of best-management practice for oil palm peat systems: about 320 seedlings/ha (six-week-old seedlings, two per palm point), raised from about 500 seeds (75 g), to conserve soil moisture, minimize peat subsidence, and reduce peat-fire risk (MPOB TT No. 501, 2012). In that trial on deep peat at Teluk Intan, MB cover reached 31% at 6 months, 58% at 12, 75% at 18 and 78% at 24 months.

Management note: Peat establishment requires careful water-table management. MB must still be maintained around palm circles.

Immature oil palm, lower management capacity

Alternative: PJ + CM mix

Where plantation teams cannot maintain active MB circle management, a PJ and CM mixture provides good ground cover with less aggressive growth. CM tolerates acidic clay soils and wet conditions; PJ tolerates acid soils and temporary waterlogging. Both are easier to manage around young palms than MB. For a mixture, the quantity of each species is set on the quotation for your site.

Replanting phase (slopes)

Recommended: legume mix that includes PJ

During replanting, erosion control is the priority. In young rubber in Côte d'Ivoire, a Pueraria cover in the inter-row gave 88% less runoff and 98% less soil loss than bare soil on 1 m2 plots over three years; adding spread logging residues almost eliminated both (Perron et al. 2024). While this data comes from rubber systems, the erosion-control mechanism applies to oil palm replanting on slopes. PJ's moderate growth habit suits slope management better than MB's aggressive climbing.

Mature oil palm (closed canopy)

Limited options under full shade

Most legume cover crops decline under closed oil palm canopy. Calopogonium caeruleum (CC) tolerates heavy shade and is one of the few legume covers that persists under mature oil palm (Tropical Forages); it performs best on well-drained sites. Centrosema pubescens (CP) also performs in partial shade. However, maintaining active legume cover under mature oil palm is difficult and may not be practical in all systems.

Mixed-species systems

Use multiple species for resilience

Many plantations use two or three species together: MB for fast ground cover in open areas, PJ for inter-rows, and CM or CP for wetter or shadier patches. Species selection should match microsite conditions rather than using a single species across the entire block.