Cover Crops for Oil Palm Replanting in Indonesia

Replanting is the critical window to establish a leguminous cover crop in Indonesian oil palm. When an old stand is felled, the ground is left cleared and exposed before the new canopy forms, so a fast cover controls erosion, fixes nitrogen to lower early fertiliser cost, suppresses weeds, and protects the soil through the immature years. A fast pioneer gives rapid cover, then vigorous and longer-lived legumes carry it forward. SoilBoost EA supports soil recovery on cleared replant land.

Aerial view of an Indonesian oil palm replanting block with young palms and establishing ground cover on cleared land

At a glance

  • Why replanting matters: cleared, exposed soil and an immature phase before canopy closure leave the ground vulnerable to erosion and weed pressure
  • Establish cover early: the replant window is the best time to put a protective legume cover down on bare land
  • Fast pioneer: Calopogonium mucunoides (CM) for rapid early cover, 4 to 6 kg/ha
  • Core legumes: Pueraria javanica (PJ) 4 to 6 kg/ha; Mucuna bracteata (MB) nursery-transplanted at about 320 seedlings/ha, roughly 85 to 100 g of seed per hectare
  • Shade-persistent for canopy closure: Centrosema pubescens (CP) 3 to 4.5 kg/ha; Calopogonium caeruleum (CC) 3 to 4.5 kg/ha
  • Lower early fertiliser cost: legume nitrogen fixation contributes to the system as the cover decomposes. We do not put a percentage on the saving.
  • Soil support: SoilBoost EA humic acid conditioner (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)
  • PSR fit: cover crops fit naturally into a smallholder replanting (peremajaan) programme

Replanting is the critical window for ground cover

Replanting (peremajaan) is a recurring reality across Indonesia's oil palm estates and smallholdings. When an old stand is felled and the new generation is still immature, the ground is left cleared and exposed, often on sloping terrain, before any new canopy has formed. This is the single best moment to establish a leguminous cover crop, because the cover does most of its work during the years before canopy closure:

  • Erosion control on cleared land: a living legume cover protects bare, exposed replant soil and slows surface runoff on sloping ground.
  • Nitrogen fixation: legumes fix atmospheric nitrogen in partnership with soil bacteria, returning it to the system as the cover decomposes.
  • Weed suppression: a dense legume mat shades out weeds and reduces manual and chemical weeding on young blocks.
  • Soil moisture and organic matter: ground cover moderates soil temperature, reduces evaporation, and feeds soil organic matter through biomass turnover.

Species for replanting

Calopogonium mucunoides (CM): fast pioneer

CM establishes quickly and gives rapid early ground cover, making it the workhorse pioneer on cleared replant land in the first months after planting. Seeding rate: 4 to 6 kg/ha, or 1 to 3 kg/ha as the CM component of a mixture.

Pueraria javanica (PJ): vigorous core legume

PJ (tropical kudzu) is a vigorous, widely used core legume for oil palm, valued for biomass and nitrogen contribution while the canopy is open. The clearest published measurement 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). That is a measured upper reference point from one site, not a design value, and the same trial found the cover reduced the drought resilience of the young trees on water-limited ground. PJ thins as the canopy closes. Seeding rate: 4 to 6 kg/ha, or 3 to 7.5 kg/ha as the PJ component of a mixture.

Mucuna bracteata (MB): nursery-raised, long-lived cover

MB produces dense, persistent ground cover and is the shade-tolerant species of the group, so it carries the cover on as the new canopy matures. It is nursery-raised and transplanted at about 320 seedlings/ha (roughly 85 to 100 g of seed/ha), never broadcast like the other species: a kilogram-per-hectare rate for MB is wrong by a factor of roughly forty. Isotope work puts MB at 67 to 84% of its nitrogen drawn from the atmosphere (Cheah, Zaharah & Aminuddin 2010, Oil Palm Bulletin 60); we do not publish an absolute kg N/ha figure for MB, because none we can trace is sound.

Centrosema pubescens (CP) and Calopogonium caeruleum (CC): shade persistent for canopy closure

As the new palm canopy closes and light at ground level drops, the shade-persistent legumes carry the cover forward. CP seeding rate: 3 to 4.5 kg/ha (0.5 to 3 kg/ha in a mixture). CC seeding rate: 3 to 4.5 kg/ha (0.6 to 1.5 kg/ha in a mixture). These species are often combined with pioneers in a mixed cover strategy: 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 - an institutional recommendation from a peat trial rather than a primary field measurement.

Bare exposed soil during oil palm replanting in Indonesia, showing why early cover crop establishment matters on cleared land

Nitrogen contribution to reduce early fertiliser cost

On the acidic mineral soils common across Indonesian oil palm regions, where nutrients can leach under heavy rainfall, the nitrogen contributed by a healthy legume cover is a useful complement to the estate fertiliser programme during the immature years. Legumes fix atmospheric nitrogen and release it gradually as biomass decomposes, helping maintain nitrogen in the system and supporting lower early fertiliser cost on a young replant. This supports, rather than replaces, a planned fertiliser regime. How much arrives depends on how much biomass the cover actually grows on your block, and applied mineral nitrogen suppresses fixation, so we do not publish a fertiliser-replacement figure.

Erosion and runoff control on cleared replant land

Cleared replant land is exposed to heavy tropical rainfall before any canopy has formed. On sloping ground this can drive significant surface runoff and erosion. A living legume cover protects the soil surface, slows runoff, and holds soil in place through the immature years. Establishing a fast pioneer early, then carrying the cover forward with vigorous and shade-persistent legumes, keeps the ground protected from clearing through to canopy closure.

SoilBoost EA to support soil recovery at replant

SoilBoost EA is a Leonardite-derived humic acid soil conditioner manufactured exclusively for Chemiseed Sdn. Bhd. (Malaysia) and Kudzu Seeds Trading. It has pH 3.84 and 0.45% sulfur as sent (25.81% sample moisture), equivalent to 0.61% on a dry-weight basis. Typical analysis. A certificate of analysis for the batch supplied is available on request. On cleared replant soil that has carried a previous stand for many years, a humic acid conditioner supports soil condition, structure, and nutrient retention as the new planting establishes. SoilBoost EA is applied by broadcast at 50 to 100 kg/ha or by drench at 10 to 15 kg/ha. It is a soil conditioner: it is not a fertiliser substitute and not a disease treatment.

Cover crops in a smallholder replanting (PSR) programme

Indonesia's national smallholder oil palm replanting programme, Peremajaan Sawit Rakyat (PSR), provides government support and funding for independent smallholders replanting their oil palm, administered through BPDPKS. Cover crops fit naturally into a peremajaan programme: the replant window is exactly when a protective legume cover is most valuable, holding cleared soil, suppressing weeds, and contributing nitrogen while the young palms establish. Chemiseed supplies the cover crop seed and SoilBoost EA for replanting blocks; we do not administer the PSR programme itself.

Frequently asked questions

Why is replanting the best time to establish a cover crop?

At replanting the ground is cleared and exposed before the new canopy forms, so it is most vulnerable to erosion and weeds. Establishing a legume cover early protects the soil through the immature years and contributes nitrogen and organic matter as the new palms grow.

Which cover crop suits oil palm replanting blocks in Indonesia?

On replant land the priority is fast, protective ground cover on exposed and often sloping soil. A fast pioneer like Calopogonium mucunoides (4 to 6 kg/ha) established early, then carried forward with Pueraria javanica (4 to 6 kg/ha), protects the soil through the immature years. Plan the handover before canopy closure: PJ thins as light falls, Mucuna bracteata is the shade-tolerant option, and CP and CC are the shade-persistent successors.

How much nitrogen does a legume cover contribute at replant?

We give a measured reference point rather than a planning figure. For Pueraria javanica, about 250 kg N per hectare per year accumulated in aboveground biomass at 85 to 93% Ndfa in one rubber-intercrop trial in northeast Thailand (Clermont-Dauphin et al. 2016). For Mucuna bracteata, 67 to 84% of its nitrogen drawn from the atmosphere (Cheah, Zaharah & Aminuddin 2010), which is a proportion rather than a quantity. We do not publish a fertiliser-replacement percentage.

Do cover crops fit the PSR (Peremajaan Sawit Rakyat) programme?

Yes. PSR provides government support for smallholder oil palm replanting through BPDPKS, and the replant window is exactly when a protective legume cover is most valuable. Cover crops fit naturally into a peremajaan programme. Chemiseed supplies the seed and SoilBoost EA; it does not administer PSR.

What does SoilBoost EA do at replant?

SoilBoost EA is a humic acid soil conditioner that supports soil condition, structure, and nutrient retention on cleared replant land. It is applied at 50 to 100 kg/ha by broadcast or 10 to 15 kg/ha by drench. It is not a fertiliser substitute.

Where can I buy cover crop seeds for replanting in Indonesia?

Contact Windhi, Chemiseed's Indonesia representative, for a quotation. She supports the whole process in Bahasa Indonesia.

Get a quote for your replanting programme

Minta penawaran or Hubungi Windhi (perwakilan Indonesia):

Related pages and products

References: The Pueraria javanica nitrogen figure comes from Clermont-Dauphin, C. et al. (2016), Agriculture, Ecosystems & Environment 217: 79-88, a single rubber-intercrop trial in northeast Thailand, and is nitrogen accumulated in aboveground biomass. Mucuna bracteata Ndfa of 67 to 84% is from Cheah, Zaharah & Aminuddin (2010), MPOB Oil Palm Bulletin 60. Mixture rates follow MPOB TT No. 501 / Information Series 588 (June 2012), an institutional best-management-practice recommendation from a peat trial. Mucuna bracteata nursery transplanting at about 320 seedlings/ha follows MPOB best-management practice; broadcast rates for PJ, CM, CP and CC are Chemiseed's reconciled agronomic references. PSR (Peremajaan Sawit Rakyat) is the Indonesian government's smallholder oil palm replanting programme administered through BPDPKS; programme details and support levels are set by the government and have changed over time.