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| 8) K-deficiency resulting in reduced ear diameter and grain weight in maize. Photo credit: J.J. Volenec | 9) Reduced ear size and incomplete grain filling cause by K deficiency in maize. Photo credit: J.J. Volenec | Corn hybrid differences (to the left and right of photo center) in K deficiency symptoms on a low K soil. Photo credit: Tony J. Vyn |
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| Control ( no P and K) on left of yellow flag versus Banded P and K for strip-till corn in 2003. Photo credit: Tony J. Vyn | Deep banded (15 cm depth) P and K on left of yellow flag versus broadcast P and K to the right of the yellow flag. Total P and K applied at similar rates; all corn was planted after strip-tillage. Photo date: June, 2003. Photo credit: Tony J. Vyn | Because K plays such a prominent role in cell growth, K deficient plants may be shorter even when they exhibit few or no foliar symptoms of deficiency. K deficiency also delays development, including tasseling and pollination in corn. Photo credit: S.M. Brouder |
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| Corn stalk diameters and the lengths of internodes are reduced by K deficiency. Photo credit: S.M. Brouder | In K-deficient corn, ears may be inserted at a lower node when compared to K-sufficient plants. Combing ear insertion at a lower-node with shortened internode lengths results in K-deficient plants having ears much closer to the ground. Photo credit: S.M. Brouder | Because of slower growth and development, K-deficient corn may pollinate later than K-sufficient corn. Photo credit: S.M. Brouder |
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| Since K is mobile in plants, foliar symptoms are typically displayed on older leaves. Foliar symptoms of K deficiency are marginal chlorosis and necrosis of lower leaves. Photo credit: S.M. Brouder | Finding foliar symptoms of K deficiency in corn requires careful examination of the lowest or oldest leaves. The photo inset shows the 4th true leaf of a K sufficient (upper leaf) and K deficient plant (lower leaf). Photo credit: S.M. Brouder | Late season, field-scale K deficiency symptoms in corn (right) compared to K-sufficient plants (left). K-deficiency accelerates crop maturation and leaf senescence. The insert shows premature blacklayer formation in the small seeds from K-deficient corn plants (left) compared to seeds from K-fertilized plants (right). Photo credit: J.J. Volenec |
K Diagnostics | Alfalfa | Corn | General Crops | Soybeans