Legume before rice: lifting Philippine paddy yield

Growing a legume before rice raises the following rice crop's yield by about 15.7 percent on average. A global meta-analysis of legume-rice rotations across 1,483 data pairs (Yao et al. 2025, One Earth) found a 15.7 percent yield advantage in the rice that follows a legume, compared with rice without that rotation. The legume fixes nitrogen and feeds the soil, so the rice starts on richer ground. For Philippine paddy farmers, this is a way to lift yield and build soil fertility at the same time. Here is how it works and how to put it into practice.

How much does a legume before rice raise yield?

A legume before rice raises the next rice crop's yield by about 15.7 percent on average, based on a global meta-analysis of 1,483 paired comparisons of legume-rice rotations. That figure is an average across many sites and systems, so your result will vary with soil, the legume used, and how well it is grown and incorporated. But the direction and size of the effect are well supported across a large dataset: on average, rice following a legume outyields rice that does not.

How does a legume before rice affect my nitrogen fertiliser?

A legume green manure adds nitrogen to the soil ahead of the rice, but how much the rice receives depends on how much biomass the legume produced and how well it was incorporated, so there is no fixed figure to take off your fertiliser plan. Legume cover contributes nitrogen; adjust your fertiliser programme only after soil and leaf analysis shows what the cover supplies on your block.

Why does a legume rotation also help the soil?

A legume rotation helps the soil by adding nitrogen, organic matter, and carbon, which builds fertility beyond the single following crop. The legume-rice rotation research found higher rice yields and, in about two-thirds of cases (65.8%), higher soil organic carbon as well. Fixed nitrogen feeds the rice; the legume residue adds organic matter that improves soil structure, biology, and the soil's capacity to hold nutrients and water. Over repeated cycles this compounds: better soil supports better crops. So the benefit is both immediate, the yield bump and the nitrogen the legume supplies to the next rice, and cumulative, a soil that gets steadily healthier.

How do I fit a legume into a Philippine rice system?

Fit a legume into the fallow or off-season window before rice, grow it for biomass, then incorporate it as green manure ahead of transplanting. The practical sequence is: sow a suitable green-manure legume in the gap before the rice crop, let it grow and fix nitrogen, then turn it into the soil before it sets seed so the nitrogen-rich biomass breaks down for the rice. Time the incorporation so the residue has begun decomposing when the rice goes in. Inoculate the legume seed with the right rhizobia on acid soils so it fixes nitrogen well. Then adjust your nitrogen fertiliser only after soil and leaf analysis shows what the legume has supplied, and watch the rice over the season.

FAQ

How much more rice will I get after a legume?

On average about 15.7 percent more, based on a global meta-analysis of 1,483 paired comparisons of legume-rice rotations. Your result varies with soil, the legume, and how well it is grown and incorporated, but on average rice following a legume outyields rice that does not.

Does a legume green manure change how much nitrogen fertiliser I need?

A legume green manure adds nitrogen to the soil, and how much reaches the rice depends on how much legume biomass you grow and incorporate. Legume cover contributes nitrogen; adjust your fertiliser programme only after soil and leaf analysis shows what the cover supplies on your block.

When should I incorporate the legume before rice?

Incorporate the legume as green manure before it sets seed and ahead of transplanting, timing it so the nitrogen-rich biomass has begun to decompose when the rice goes in. This releases the fixed nitrogen and organic matter into the soil for the rice crop. On acid soils, inoculate the legume seed first so it fixes nitrogen well.

Get green-manure legume seed for your paddy rotation

We supply green-manure and cover-crop legume seed, germination- and purity-tested to ISTA and AOSA methods, with inoculation advice for acid soils, to fit a legume into your rice rotation. For seeding rates, request a quote or message us on WhatsApp at +60 17-237 4058.

Sources

• Yao, W., Yang, Y., Beillouin, D., et al. (2025). Legume-rice rotations increase rice yields and carbon sequestration potential globally. One Earth 8(2): 101170. https://doi.org/10.1016/j.oneear.2024.12.006
• Zhao, J., Chen, J., Beillouin, D., Lambers, H., Yang, Y., Smith, P., Zeng, Z., Olesen, J.E. and Zang, H. (2022). Global systematic review with meta-analysis reveals yield advantage of legume-based rotations and its drivers. Nature Communications 13: 4926. https://doi.org/10.1038/s41467-022-32464-0