COMPLIANCE INFO_FILE 1 2003-2006

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Molybdenum deficiency symptoms are similar to those of nitrogen. Since molybdenum deficiencies are very uncommon symptoms are rarely seen. Zln6 Zinc is partly mobile in wheat and barley. In these crops pale yellow chlorotic areas appear on middle leaves, halfway up the stem. Chlorotic symptoms first develop in the lower half or mid-section of the leaf followed by grey or dark brown necrosis of the leaf. Generally, stems are very short and often fan-shaped with leaves crowded together at the top. Zinc deficient beans are stunted and older leaves are smaller and narrower.The older leaves may have light blotches between the veins. Younger leaves will have a more normal healthy green color but may be smaller. In flax, a zinc deficiency can cause grayish-brown spots in the younger leaves with shortened internode spaces and stunted appearance. In corn, symptoms occur within a few weeks of emergence as light yellow bands on the youngest leaves. The most severe symptoms occur on the youngest leaves from the unfolding bud, referred to as "white-bud". Old leaves remain dark green and appear healthy. In a prolonged case of deficiency the middle leaves develop pale yellow interveinal chlorosis near the tips. A zinc deficiency prevents the elongation of internodes and leaves, which results in short stems with the leaves crowded together at the top in a fan-shaped appearance. Note that zinc deficiency symptoms are similar to those of manganese and iron in some crops. Soil Sampling and Testing Soil tests aid in determining whether a particular nutrient is responsible for poor production and provides the basis for deciding the type and amount of fertilizer needed to correct a nutrient shortage. A soil sample used for laboratory analysis must consist of a composite of a number of samples taken from the field. The DTPA(diethylenetriamine pentaacetic acid) method is used to extract the metal micronutrients. Hot water is used to extract boron. Either water or sodium nitrate is used to extract chlorine.Analytical results are usually given in parts per million (ppm). No soil test has proven particularly useful in predicting the availability of molybdenum. The micronutrients that are normally tested for are boron, copper, iron, manganese, and zinc. Surface soil samples(0-1 5 cm)should be taken from both the affected area and an adjacent area of good crop growth for comparison. The general range levels used for determining when to add micronutrients for improving crop production are shown in table 2. When a soil sample tests low in a micronutrient, a potential micronutrient deficiency may occur. Some soils with low micronutrient levels at the surface(0- 1 5 cm)do not respond to fertilization because they have higher levels of the nutrient in the subsoil. Tissue Sampling and Testing Plant tissue tests can aid in determining if a particular nutrient is responsible for poor crop growth.When a deficiency is detected by tissue sampling, a reduction in yield due to restricted crop growth has already occurred. As with soil analysis, tests involving plant tissue must be calibrated with field fertilizer trials. Calibration in this case is far more complex than for soil tests. The reason is that measured nutrient concentration,which is the basis of the tests, varies considerably with the stage of plant development and the portion of the plant sampled. Table 2. Range levels of micronutrients in soils. Deficient JF7WJium 11 Adequate Boron (Hot Water Extractable-ppm) 0.0-0.4 0.5 - 1.2 > 1.2 Chlorine(Water Extractable-ppm) 0.0-8.0a-71 - - (: Copper(DTPA Extractable-ppm) 0.0 -0.2b 0.3- 1.0 > 1.0 11 0.0-0.5c 0.6-1.0 > 1.0 0.0-2.5d - 71 > 2.5 Iron (DTPA Extractable-ppm) 0.0-2.0 2.0-4.5 —>4.5 Manganese(DTPA Extractable-ppm) 11 0.0- 1.0 - > 1.0 Zinc(DTPA Extractable-ppm) 11 0.0-0.5-71 0.5-1.0 > 1.0 aThis level is used by some labs as a critical level for recommending Cl for disease suppression in cereals. bBrown and Dark Brown soil areas °Black and Grey Wooded soil areas dOrganic soils