Plant · P-237

Soybean

Glycine max (L.) Merr.

Soybean is a short-day crop that will not flower until daylight drops under thirteen hours, so growers pick a maturity group rather than hoping the calendar cooperates. The seed is a major world source of both oil and protein, cooked into soups, stews, meat substitutes, miso, tempeh and milk, though the raw mature seed is toxic and must be thoroughly cooked - only the sprouts are safe raw. On alkaline, high-calcium-carbonate ground the plant can develop iron deficiency chlorosis, an interveinal yellowing that cuts yield, so choosing an iron-tolerant variety matters more than fertilizing around the problem. As livestock feed it is the reference protein source worldwide, but raw seed carries trypsin inhibitors and estrogen-like compounds that make heat treatment - not just soaking - essential before pigs or poultry can eat it.