Micronutrient deficiencies generally have an uneven distribution in fields due to management history and natural variation in soils, and visual symptoms of micronutrient deficiencies often occur too late for effective corrective action. Soil tests for pH level can be useful for accurately monitoring problems and are recommended in seeking management solutions. Application of micronutrient fertilizers can also be restricted to deficient areas in order to minimize the risk of exposing plants to an excess of nutrients, which could lead to plant damage (Wortmann et al., 2013).
Corn is highly sensitive to zinc. There is a high probability that the crop will respond positively to applied zinc in the case of low soil zinc availability or if the soil meets any of the following criteria:
Zinc levels of 0.8 ppm are adequate for crop growth, but if the soil content of zinc drops to 0.4 ppm or less, a zinc application is highly recommended. The first symptoms of zinc deficiency will be on new leaves with interveinal striping ranging from the base to the tip. White or yellow broad bands will occur on either side of the midrib, but the leaf margins and tips will remain green (Figure 4).
Figure 4. Corn leaf showing zinc deficiency, characterized by interveinal stripes in the center of the leaf and surrounded by green borders against the broad yellow or white bands.
Corn is a good indicator crop of low soil zinc levels. If the corn crop does not exhibit a need for added zinc, other crops are not likely to need zinc fertilizer. The numerous zinc fertilizer products are broken out into categories of varying components, such as inorganics, synthetic chelates, natural compounds, soluble and insoluble products, and other variable sources of zinc. Sources of zinc for fertilization should be chosen on the basis of solubility, cost, ease of application, and residual effects. Soluble sources of zinc are recommended for soils with high pH.
PIONEER® brand products are provided subject to the terms and conditions of purchase which are part of the labeling and purchase documents.
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. Product performance is variable and depends on many factors such as moisture and heat stress, soil type, management practices and environmental stress as well as disease and pest pressures. Individual results may vary.