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Designing a cover-crop seed mix for Philippine estates

Kudzu Seeds Trading · Updated

Seeds of five legume cover crops side by side: Pueraria javanica, Calopogonium mucunoides, Centrosema pubescens, Calopogonium caeruleum and Mucuna bracteata

A good cover-crop seed mix for a Philippine estate combines a fast establisher, a long-term nitrogen fixer, and a shade-tolerant species so the cover holds up as the canopy closes. Pueraria javanica, Calopogonium caeruleum, and Centrosema pubescens each do something different, and blending them gives more reliable ground cover across the life of the planting than any single species. This article sets out what each species contributes, our recommended seeding rate for each species sown alone, and how the mix for your site is set.

Note the naming point up front: Pueraria javanica is a managed tropical legume, not the invasive kudzu (Pueraria montana). It is the workhorse of tropical cover-crop mixes, but it can climb and smother other plants in the humid tropics (Tropical Forages), so it needs managing like any vigorous cover. See Pueraria javanica vs invasive kudzu for the full naming explanation.

Why mix species instead of planting one?

You mix species because no single cover crop is fast, persistent, and shade-tolerant all at once. A blend covers the gaps: one species establishes quickly to protect bare soil early, another fixes nitrogen and persists for years, and a third keeps producing as the tree canopy shades the interrow. A single-species cover can do part of this, but a mix gives more resilient ground cover across changing light and season. It also spreads risk: if one species struggles on a patch of your soil, the others carry the cover.

What does each species contribute?

Pueraria javanica is the main nitrogen fixer and ground-cover legume of the mix. It establishes vigorously, suppresses weeds, and in one trial under young rubber in northeast Thailand accumulated up to 250 kg of nitrogen per hectare per year in above-ground biomass (Clermont-Dauphin et al. 2016); expect less under a closing canopy or on water-limited ground. Recommended seeding rate (sown alone): 10 kg per hectare (our recommendation). For the record, in the conventional cover mixture used as a treatment in MPOB's peat trial (MPOB TT No. 501) it was sown at 4 kg per hectare alongside Centrosema and Calopogonium caeruleum.

Calopogonium caeruleum is the shade specialist that keeps the cover going under a closing canopy. Tropical Forages describes it as one of the most shade-tolerant tropical legumes: its productivity is relatively constant at 60 to 100 percent light transmission, it still yielded 1 to 1.5 tonnes of dry matter per hectare per year under mature oil palm at about 10 percent light, and its leaf fall returns large amounts of dry matter to the soil. Recommended seeding rate (sown alone): 5 kg per hectare.

Centrosema pubescens adds another shade-tolerant, nitrogen-fixing legume that complements the other two and helps the cover persist as conditions change. It is a long-used plantation cover legume valued for its tolerance of shade and its contribution to a durable, mixed sward. Recommended seeding rate (sown alone): 10 kg per hectare.

How are seeding rates set for a mix?

Our recommended seeding rates are for one species sown alone: Pueraria javanica 10 kg per hectare, Centrosema pubescens 10 kg per hectare and Calopogonium caeruleum 5 kg per hectare (our recommendation). Recommended planting method: drill or in holes. For a mixture, the quantity of each species is set on the quotation for your site, taking account of seed quality, soil, and how fast you need full cover. For the record, MPOB's peat trial (MPOB TT No. 501, Table 1 treatment C2) used PJ 4 + CP 3 + CC 1 = 8 kg per hectare, which MPOB calls conventional LCC, with 5 g of Rhizobium (RRI strain) inoculant per kg of seed.

Dense tropical legume cover crop with broad leaves
A legume cover established across the inter-row.

How do I match the mix to my site?

Match the mix to your light, soil, and timeline; the quantity of each species is then set on the quotation for your site. On a fresh, open replant where you need quick cover, weight the mix toward the fast-establishing Pueraria. Where the canopy will close soon or is already heavy, increase the shade-tolerant Calopogonium and Centrosema share so the cover survives into the mature phase. On acid soils, pair the seed with the right inoculant so the legumes actually fix nitrogen. And always order seed with germination and hard-seed figures so you can set a realistic rate rather than guessing.

FAQ

What three species make a good Philippine cover-crop mix?

A reliable mix combines Pueraria javanica as the main nitrogen fixer and ground cover, Calopogonium caeruleum as the shade specialist that persists under a closing canopy, and Centrosema pubescens as an additional shade-tolerant legume. Together they cover fast establishment, long-term nitrogen fixation, and shade tolerance, which no single species does alone.

How much seed per hectare for a cover-crop mix?

Our recommended seeding rates are for one species sown alone: Pueraria javanica 10 kg per hectare, Centrosema pubescens 10 kg per hectare and Calopogonium caeruleum 5 kg per hectare. 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) used Pueraria 4 + Centrosema 3 + Calopogonium caeruleum 1 = 8 kg per hectare, which MPOB calls conventional LCC, with Rhizobium inoculant.

Is the Pueraria in cover mixes the invasive kudzu?

No. Pueraria javanica is a managed tropical legume, not the invasive kudzu (Pueraria montana). It is also classified as Neustanthus phaseoloides and is the standard nitrogen-fixing backbone of tropical plantation cover mixes, established and maintained as a managed cover crop.

Get seeding rates for your estate

We supply Pueraria javanica, Calopogonium caeruleum, and Centrosema pubescens seed, germination- and purity-tested to ISTA and AOSA methods, and can design a mix and seeding rate for your block. Request a quote, or message us on WhatsApp at +60 17-237 4058.

Sources

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