Cover Crops for Oil Palm Replanting in Malaysia

Cover Crops for Oil Palm Replanting in Malaysia

Establishing legume ground cover during the replanting window, by Chemiseed Sdn. Bhd.

At a glance

Why the replanting window is the critical time

Oil palm runs on a roughly 25-year cycle. At replanting, the old palms are felled and the ground is opened up. For the first few years the new palms are immature and the canopy is open, which means a large share of the soil surface is bare and exposed to sun and heavy tropical rainfall. This is exactly the phase where erosion, surface runoff, and weed invasion do the most damage, and it is also the phase where a cover crop delivers the most value.

Establishing legume ground cover at replanting means the cover is already working through the whole immature period: holding soil in place, feeding nitrogen into the rootzone, and crowding out aggressive weeds before they take hold. Waiting until the palms are older is far less effective, because a closing canopy thins out PJ and the other broadcast pioneers. For more on matching species to each phase, see our best cover crop for oil palm guide and the complete cover crops guide.

Species for replanting

Calopogonium mucunoides (CM): fast pioneer

CM establishes quickly and gives early ground cover on freshly cleared land, which is why it is often used as the pioneer component of a replanting mix. It tolerates acidic soils and provides rapid biomass while slower species fill in. Sow at 4 to 6 kg/ha, or 1 to 3 kg/ha as the CM component of a mixture.

Pueraria javanica (PJ): durable cover for the open canopy

PJ is a workhorse legume for plantation ground cover. The clearest published nitrogen measurement for it comes from a single rubber-intercrop trial in northeast Thailand, where the cover accumulated about 250 kg of nitrogen per hectare per year in aboveground biomass at 85 to 93% Ndfa (Clermont-Dauphin et al. 2016, Agriculture, Ecosystems & Environment 217:79-88). Treat that as a measured upper reference point from one site rather than a design value, and note that the same trial found the cover reduced the drought resilience of the young trees on water-limited ground. PJ tolerates a wide pH range and gives durable, longer-lived cover than CM alone, but it thins as the canopy closes. Sow at 4 to 6 kg/ha, or 3 to 7.5 kg/ha as the PJ component of a mixture. See Pueraria javanica (PJ) seed.

Mucuna bracteata (MB): by nursery transplant

MB is established from nursery-raised seedlings, not broadcast. The common reference rate is about 320 seedlings per hectare (roughly 85 to 100 g of seed per hectare raised in the nursery), so a kilogram-per-hectare rate for MB is wrong by a factor of roughly forty. MB produces a thick mat that is strong on weed suppression and biomass, and it is the shade-tolerant species of the group, which is why it carries the cover on under a maturing canopy. It is vigorous and needs active palm-circle maintenance so it does not climb the young palms. Isotope work puts MB at 67 to 84% of its nitrogen drawn from the atmosphere (Cheah, Zaharah & Aminuddin 2010, Oil Palm Bulletin 60); we publish no absolute kg N/ha figure for MB because none we can trace is sound.

Centrosema pubescens (CP) and Calopogonium caeruleum (CC): the shade-persistent successors

Sow these before canopy closure so they are established when light at ground level falls and PJ thins. CP 3 to 4.5 kg/ha (0.5 to 3 kg/ha in a mixture); CC 3 to 4.5 kg/ha (0.6 to 1.5 kg/ha in a mixture). The best-cited published mixture is MPOB TT No. 501 (Information Series 588, June 2012), Table 1 treatment C2: PJ 4 : CP 3 : CC 1, total 8 kg/ha, with 5 g of Rhizobium (RRI strain) inoculant per kg of seed. Treatment C4, where MB carries part of the cover, is PJ 3 + CP 1 = 4 kg/ha. Both are institutional best-management-practice recommendations from a peat trial, not primary field measurements, and MPOB does not state whether the totals are per gross hectare or per interrow hectare actually sown.

Nitrogen contribution reduces early fertiliser cost

Legume cover crops fix atmospheric nitrogen through root nodules and return it to the soil. During the immature phase, when young palms are building their root and frond system, this biological nitrogen supplements the fertiliser programme and can reduce early synthetic nitrogen requirements. Cover crops supplement fertiliser, they do not replace it: keep adjusting your fertiliser to soil and foliar analysis rather than to cover crop presence alone. We will not put a percentage on the saving, because how much nitrogen arrives depends on how much biomass the cover actually grows, and applied mineral nitrogen suppresses fixation.

Erosion and runoff control on cleared replant land

Bare replant soil on any slope is highly vulnerable to erosion and surface runoff in tropical downpours. A living legume cover intercepts rainfall, binds the surface with roots, and slows runoff, keeping topsoil and applied nutrients on site instead of washing into drains and waterways. This is the headline reason to get cover established at the replanting stage rather than later. For state-specific guidance, see our pages for Sabah and Sarawak.

SoilBoost EA to support soil recovery at replant

Replanting is a natural moment to rebuild soil condition before the new stand establishes. SoilBoost EA is a humic acid soil conditioner manufactured exclusively for Chemiseed Sdn. Bhd. (Malaysia) and Kudzu Seeds Trading (humic acid, pH 3.84, 0.45% sulfur as sent or 0.61% on a dry-weight basis, Leonardite-derived; typical analysis, certificate of analysis for the batch supplied on request). It is used to support soil structure and the soil conditions that help cover crops and young palms establish. Apply by broadcast at 50 to 100 kg/ha, or by drench at 10 to 15 kg/ha. SoilBoost EA is a soil conditioner, not a fertiliser substitute and not a disease treatment.

Cover crops fit into a replanting programme

Malaysian smallholder oil palm replanting is supported by a government replanting scheme administered for smallholders, commonly referenced at around RM14,000 per hectare. Cover crop establishment fits naturally into a planned replanting programme alongside felling, land preparation, and new palm planting. For background on the scheme, see our blog article on oil palm replanting support in Malaysia. We do not administer the scheme and do not advise on eligibility; refer to the official programme for those details.

Frequently asked questions