PJ vs CM vs CP vs MB vs CC: cover crop comparison guide
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Cover crop comparison guide: PJ vs CM vs CP vs MB vs CC
PJ, CM, CP, MB, and CC each excel in different conditions. The best choice depends on your soil pH, shade availability, rainfall, slope, and production goals. This guide helps plantation managers select the optimal cover crop species or mixture.
Full comparison table
| Criteria | PJ (Pueraria javanica) | CM (Calopogonium mucunoides) | CP (Centrosema pubescens) | MB (Mucuna bracteata) | CC (Calopogonium caeruleum) |
|---|---|---|---|---|---|
| Seeding Rate | 10 kg/ha sown alone | 10 kg/ha sown alone | 10 kg/ha sown alone | 1 kg/ha sown alone, drilled or planted in holes; nursery seedlings are another option (MPOB's deep-peat trial: 320 seedlings/ha from about 500 seeds, 75 g, MPOB TT No. 501; Samedani et al. 2015: 680 seedlings/ha on mineral soil) | 5 kg/ha sown alone |
| Annual N measured (kg N/ha/yr) | Up to 250, accumulated in above-ground biomass in one trial under young rubber, NE Thailand (Clermont-Dauphin et al. 2016). Not a design value; less under a closing canopy or on drought-prone ground. | No verified annual rate | No verified annual rate | No single routine annual rate is asserted | No verified annual rate |
| Share of N from fixation (Ndfa) | 85-93% (same trial) | Not established | Not established | 67-84%, 15N isotope dilution under three-year-old oil palm on Jawa Series soil (Cheah, Zaharah & Aminuddin 2010, Oil Palm Bulletin 60) | 28-75% in one Papua New Guinea oil palm study (Pipai et al. 2023); no general figure |
| Biomass-N stock (kg N/ha) | Not reported separately | Not established | Not established | Not established | Not established |
| Shade Tolerance | Moderate while the canopy is open; PJ thins as the canopy closes | Moderate | High: one of the two shade-persistent successors | High through canopy maturation, which is why it is used under maturing oil palm | High: the other shade-persistent successor |
| Drought Tolerance | Moderate | Moderate | Low-Moderate | Low | Moderate-High |
| Biomass (dry matter) | 5 to 10 t DM/ha in pure stands (Tropical Forages) | 4 to 6 t DM/ha/yr under cutting every 9 to 12 weeks (Tropical Forages) | No figure published by our sources | Vigorous; we do not quote a single tonnage | 3 to 7 t DM/ha/yr in the open; 1 to 1.5 under mature oil palm (Tropical Forages) |
| Establishment | Drilled or in holes | Drilled or in holes | Drilled or in holes | Drilled or in holes, or nursery seedlings; not broadcast | Drilled or in holes |
| Best For | Open and immature blocks; hand over before canopy closure | Fast pioneer cover, acidic soils | Dense shade, acidic soils | Immature through maturing palm; heavy biomass, holds under shade | Heavy shade, slopes, long-term cover |
A note on the nitrogen rows. Annual rates, the share of nitrogen drawn from fixation (Ndfa) and biomass-nitrogen stocks are different quantities, so they sit in separate rows and a stock is never shown as an annual rate. For Centrosema pubescens and Calopogonium mucunoides, no verified species-specific nitrogen figure is published. The PJ figure is from Clermont-Dauphin et al. (2016), Agriculture, Ecosystems & Environment 217:79-88.
Species recommendations
PJ: Pueraria javanica
Use PJ on open and immature blocks. Its drought tolerance is moderate. Nitrogen: up to 250 kg N/ha/yr accumulated in aboveground biomass at 85-93% Ndfa in one rubber-intercrop trial in northeast Thailand (Clermont-Dauphin et al. 2016, Agriculture, Ecosystems & Environment 217:79-88). Treat that as a measured upper reference point from a single site, not a design value. The same trial found the cover reduced the drought resilience of the young rubber trees on water-limited ground. Biomass: 5 to 10 t DM/ha in pure stands (Tropical Forages). PJ thins as the canopy closes, so plan a shade-persistent successor.
View PJ SeedsCM: Calopogonium mucunoides
Select CM as a fast pioneer cover: it covers the soil 3 to 6 months after sowing, sooner on newly cleared fertile land (PROSEA 11). Biomass: 4 to 6 t DM/ha/yr under cutting every 9 to 12 weeks (Tropical Forages). Nitrogen: no verified species-specific nitrogen figure is published for CM.
View CM SeedsCP: Centrosema pubescens
Use CP in dense shade where other legumes struggle. Best for mature rubber and dense cocoa canopies, and one of the two shade-persistent successors. Nitrogen: no verified species-specific nitrogen figure is published for CP.
View CP SeedsMB: Mucuna bracteata
MB tolerates shade through canopy maturation, which is why it is used under maturing oil palm, and it grows vigorously. Ground cover: about 100% at 6 months on mineral soil at 680 seedlings/ha (Samedani et al. 2015); on deep peat at 320 seedlings/ha, 31% at 6 months, 58% at 12, 75% at 18 and 78% at 24 (MPOB TT No. 501). Nitrogen: 67-84% of its nitrogen comes from the atmosphere by 15N isotope dilution (Cheah, Zaharah & Aminuddin 2010, Oil Palm Bulletin 60). That is a proportion, not a quantity; no absolute annual figure for MB is published from a source we can verify. Requires nursery preparation and adequate moisture.
View MB SeedsCC: Calopogonium caeruleum
Choose CC for the deepest shade and longer-term ground cover under mature canopies. It is more drought tolerant than CM and PJ and persists where faster species thin out, though it establishes slowly and can take up to 20 months to reach full cover (PROSEA 4). Suits mature oil palm and rubber, plus sloping blocks where erosion control matters. Nitrogen: no single species-specific annual fixation rate is published for CC from verified evidence; one Papua New Guinea oil palm study estimated 28 to 75% of its nitrogen from fixation (Pipai et al. 2023). Biomass: 3 to 7 t DM/ha/yr in the open and 1 to 1.5 t under mature oil palm (Tropical Forages).
View CC SeedsMixed stands
Mixture quantities: These rates are for one species sown alone. For a mixture, the quantity of each species is set on the quotation for your site. For the record, MPOB's peat trial (MPOB TT No. 501) (Information Series 588, June 2012, Table 1 treatment C2) used PJ 4 + CP 3 + CC 1 = 8 kg/ha, which MPOB calls conventional LCC, with 5 g of Rhizobium (RRI strain) inoculant per kg of seed; MPOB does not state whether the 8 kg/ha is per gross hectare or per interrow hectare actually sown.
Source of the recommended rates: Chemiseed recommendation (2026 catalogue), each for one species sown alone.
Three distinctions worth stating before you order: the total rate is not the per-species component rate; a gross hectare is not the interrow hectare you actually sow; and grazed-pasture rates are not cover crop rates.
PJ + CM: fast establishment with high early biomass. Suits newly opened and immature blocks.
Adding CP or CC: blend a shade-persistent species in from the start so it is established before the canopy closes and PJ thins out.
Frequently asked questions
Which species fixes the most nitrogen?
We cannot rank them honestly, and we would rather say that than invent an order. The measurements that exist are not comparable with each other. PJ: up to 250 kg N/ha/yr accumulated in aboveground biomass at 85-93% Ndfa, from one rubber-intercrop trial in northeast Thailand (Clermont-Dauphin et al. 2016), an upper reference point from a single site. MB: 67-84% Ndfa by isotope dilution (Cheah, Zaharah & Aminuddin 2010), a proportion rather than a quantity. CP and CM: no verified species-specific nitrogen figure is published. CC: no species-specific annual rate; one Papua New Guinea oil palm study measured 28-75% Ndfa (Pipai et al. 2023). Choose by site and canopy stage rather than by a nitrogen league table.
Can I use the same species across my entire estate?
Mixed-aged plantations benefit from species diversity. Open and immature blocks suit PJ and CM; as the canopy closes PJ thins, and MB, CP or CC should already be established to carry the cover forward. MB holds under a maturing canopy and grows vigorously; CP and CC are the shade-persistent successors. Using one species risks performance loss in unsuitable conditions.
How does direct sowing in drills or holes differ from nursery establishment?
Our recommended planting method for all five species is drill or in holes: broadcasting does not guarantee good germination, especially where the soil dries out easily. PJ, CM, CP and CC are sown as seed this way. MB is drilled or planted in holes at 1 kg/ha sown alone, or raised as nursery seedlings and transplanted, which needs nursery space, labour and adequate moisture before planting out. Request a quotation for the seed your blocks need, and we will work through the plan with you.
How do I know if my soil suits these species?
All five are grown on the acidic, highly weathered soils common in Southeast Asian plantations, but tolerance differs by species and site, and we do not publish a pH range for each species. Test your soil pH before ordering rather than assuming it, and we will check the species choice against your results.
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