| Abstract: | Abstract Micronutrients are applied alone to soils or with macronutrient fertilizers. Foliar application of Fe and other micronutrients is also practiced, and Mo is usually applied as a seed treatment. Since the soil application rates of B, Cu, Mn, and Zn are low, they are usually applied with macronutrient fertilizers by incorporation during the manufacturing process, bulk blending with or coating onto granular fertilizers, or with fluid fertilizers. Chemical reactions between the micronutrient source and the macronutrient fertilizer may occur in the manufacturing process, in storage, or after soil application. These reaction products may vary widely, so care must be taken in selecting and processing micronutrient sources and macronutrient carriers so the resulting products will be available to plants. In general, plant availability of B sources is not affected during reaction. Care must be taken to apply boronated fertilizers uniformly and to avoid excessive rates, because the range between B deficiency and toxicity is very narrow. Crop response to Cu, Mn, and Zn varies with the micronutrient rate and source, macronutrient carrier, and method of application. |
