| Nutrient | Deficiency Symptoms | Causes of Deficiency | Effect | Photo |
| Nitrogen | Pale green plants Appear first and are more severe on older leaves since nitrogen is a mobile nutrient in plants Consistent across leaves (veins are also pale) | Poor nodulation Excessive rainfall, causing nitrate leaching or denitrification due to prolonged standing water Temporary deficiency symptoms can occur under cold or dry conditions First time soybean field that was not inoculated | Slow growth Reduction in yield | |
| Potassium | Yellowing (chlorosis) that can develop into browning (necrosis) of leaf tissue along margins of older leaves In severe cases, yellowing or browning will also be evident on new leavesUneven maturity | Low soil test potassium levelsLow soil oxygen levels Low soil moisture (which reduces flow of potassium in soil solution to roots) Low soil organic matterCool temperatures | Increase disease and insect pressure Reduction in yield | |
| Phosphorus | Dark green to blue-green leaves Predominantly appears on old leaves (plant-mobile nutrient)Stunted plants | Low soil test phosphorusCold early-season soil conditions Restricted rooting (e.g., due to sidewall smearing)pH levels greater than 7.5 or lower than 6.0 | Can delay blooming and maturity Reduction in yield | Visual symptoms rare in Ontario |
| Zinc | Leaves become yellowthen turn rusty-brown while the veins stay green Uniform across the leaf Forms on younger leaves first | High levels of phosphorus fertilization Sandy soils Eroded soils Low soil test | Reduction in yield | Visual symptoms rare in Ontario |
| Magnesium | Older leaves affected first Light green to yellowing of the leaf while veins stay green Leaf margins roll down | Low soil test magnesium Acidic soils (low pH)Coarse-textured soils (sandy) | Reduction in yield | |
| Iron | Yellowing between the veins – veins remain greenSymptoms observed in youngest leaves first Plants usually recover from iron deficiency | High pHWaterlogged soils Calcareous soils High pH (greater than 7.8)Soils with high levels of copper, manganese, and/or molybdenumlow organic matter | Iron is needed for nodule formation, so if there is an iron deficiency it may lead to a nitrogen deficiency | Visual symptoms rare in Ontario |
| Manganese | Appears on youngest leaves firstA slight deficiency will appear as pale-green leaves with green veinsA severe deficiency will have almost white leaves | Low manganese levels and/or availability in high organic matter (muck) and sandy soilsHigh pH (manganese availability is greatest at pH 5.0-6.5)Waterlogged soil or poor aerationReduced root growth from soybean cyst nematodes | Reduction in yield | |
| Sulphur | Thin, elongated stems Yellowing begins in young leaves (plant-immobile nutrient) | Leaching in coarse-textured soils Low soil organic matterWaterlogged soils Acidic soils | Maturity is delayed Soybean growth is reducedProtein formation is reduced Reduced yield |
Photo Source: Jake Munroe, Horst Bohner