Pulses and grain legumes
Legumes harvested for their dry seed. The agricultural grouping is narrower than the botanical family and narrower than "legume": soybean and groundnut are legumes grown chiefly for oil, and FAO counts them separately from pulses for that reason.
An agricultural grouping. Not a taxon and not claimed to be one — cereals span two families, pulses and oilseeds overlap, and the grouping is about what the crop is grown for.
The nitrogen is the point, and it is conditional
Pulses fix atmospheric nitrogen in symbiosis with rhizobia, meeting their own requirement and leaving a residue for the following crop. The symbiosis is specific: the rhizobia that nodulate one genus frequently will not nodulate another, which is why inoculant is sold by crop and why a first-time pulse on a field can fail nutritionally while looking agronomically fine.
Applied nitrogen works against the crop
Nitrogen fertiliser suppresses fixation. A pulse given nitrogen grows on the fertiliser instead of nodulating, which costs money and removes the rotational benefit that was the reason for growing it. This is a group-level fact and one of the few places where the standard cereal instinct is actively wrong.
A break crop before it is a cash crop
In cereal-dominated rotations pulses are grown as much for what they interrupt as for what they yield: they break cereal root-disease cycles, allow different herbicide chemistry, and spread workload. That is why pulse area often tracks cereal disease pressure rather than pulse price.
Harvest is the group’s recurring difficulty
Many pulses set pods low, mature unevenly, and lodge once carrying seed, so cutting height and timing are tighter than for cereals and losses at harvest are a larger share of yield. Level, stone-free ground matters here in a way it does not for a crop harvested a metre off the ground.
Antinutrients and processing
Several pulses carry compounds — lectins, protease inhibitors, glycosides — that make the raw seed unsuitable for food or feed, and traditional preparation methods exist because of them. Soaking, cooking, germination and fermentation are not culinary preferences in this group; they are the processing step that makes the seed usable.
What this is not
- Oilseeds include legumes grown for oil rather than for the dry seed. Soybean and groundnut sit there rather than here, following FAO practice.
- Forage legumes are the same family grown for herbage, and the nitrogen goes to a companion grass rather than to a following crop.