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--- library:articles:solubility_of_micronutrients 2010/02/23 14:28
+++ library:articles:solubility_of_micronutrients 2010/03/30 16:00 current
@@ Line 12: / Line 12: @@
 Among the inorganic (non-chelate) sources in the market, the more common sources are sulfates, oxides, and oxysulfates. Sulfates such as zinc sulfate (ZnSO<sub>4</sub>) and manganese sulfate (MnSO<sub>4</sub>), are assumed to be 100% soluble. Because of the high solubility of sulfate forms, the associated micronutrients are highly available to the crop and are often considered the "benchmark" against which other sources are compared. Sulfate forms are produced by completely reacting the target nutrient with sulfuric acid, until there is only the sulfate form remaining.
 ^  Table 1 : Corn Growth (% of maximum)  |||||
-^ Percent Water solubility ^ 5.0 lbs/acre ^ 10 lbs/acre ^ 20 lbs/acre  |
+^  Percent Water solubility  ^  5.0 lbs/acre  ^  10 lbs/acre  ^  20 lbs/acre  |
 ^ ^  Zinc Applied (lbs/acre)  ||||
-| 5 | 61.7% | 62.4% | 72.5%  |
+|  5  |  61.7%  |  62.4%  |  72.5%  |
-| 10 | 64.4% | 65.6% | 78.3%  |
+|  10  |  64.4%  |  65.6%  |  78.3%  |
-| 15 | 66.8% | 68.5% | 82.9%  |
+|  15  |  66.8%  |  68.5%  |  82.9%  |
-| 20 | 69.1% | 71.3% | 86.6%  |
+|  20  |  69.1%  |  71.3%  |  86.6%  |
-| 25 | 71.3% | 73.9% | 89.5%  |
+|  25  |  71.3%  |  73.9%  |  89.5%  |
-| 30 | 73.3% | 76.3% | 91.7%  |
+|  30  |  73.3%  |  76.3%  |  91.7%  |
-| 35 | 75.2% | 78.6% | 93.5%  |
+|  35  |  75.2%  |  78.6%  |  93.5%  |
-| 40 | 77.0% | 80.7% | 95.0%  |
+|  40  |  77.0%  |  80.7%  |  95.0%  |
-| 45 | 78.6% | 82.6% | 96.1%  |
+|  45  |  78.6%  |  82.6%  |  96.1%  |
-| 50 | 80.2% | 84.5% | 97.0%  |
+|  50  |  80.2%  |  84.5%  |  97.0%  |
-| 55 | 81.7% | 86.2% | 97.7%  |
+|  55  |  81.7%  |  86.2%  |  97.7%  |
-| 60 | 83.0% | 87.8% | 98.2%  |
+|  60  |  83.0%  |  87.8%  |  98.2%  |
-| 65 | 84.3% | 89.2% | 98.7%  |
+|  65  |  84.3%  |  89.2%  |  98.7%  |
-| 70 | 85.5% | 90.6% | 99.0%  |
+|  70  |  85.5%  |  90.6%  |  99.0%  |
-| 75 | 86.6% | 91.9% | 99.3%  |
+|  75  |  86.6%  |  91.9%  |  99.3%  |
-| 80 | 87.7% | 93.1% | 99.5%  |
+|  80  |  87.7%  |  93.1%  |  99.5%  |
-| 85 | 88.7% | 94.2% | 99.7%  |
+|  85  |  88.7%  |  94.2%  |  99.7%  |
-| 90 | 89.6% | 95.3% | 99.8%  |
+|  90  |  89.6%  |  95.3%  |  99.8%  |
-| 95 | 90.5% | 96.2% | 99.9%  |
+|  95  |  90.5%  |  96.2%  |  99.9%  |
-| 100 | 91.3% | 97.1% | 100.0%  |
+|  100  |  91.3%  |  97.1%  |  100.0%  |
 Some micronutrient sources, such as zinc oxide (ZnO) are completely in the oxide form. Oxides are essentially insoluble in a single crop season, therefore unavailable to the following crop. There are some exceptions to this, such as when oxides are ground to an exceptionally fine powder and impregnated on fertilizer granules. Oxides are normally the lowest cost materials. However, because they are essentially insoluble, most agronomists consider them to be ineffective as a fertilizer source.
@@ Line 44: / Line 44: @@
-The results of this work were consistent enough that the researchers were able to develop mathematical equations to reliably predict the Zn uptake from a given rate of Zn application, based on the solubility of the fertilizer. The results of these formulas are shown in Figure 1.
+The results of this work were consistent enough that the researchers were able to develop mathematical equations to reliably predict the Zn uptake from a given rate of Zn application, based on the solubility of the fertilizer. The results of these formulas are shown in Table 1.
-When first evaluating the data in Table 1, we could conclude that applying 10 lb./A of a 5% soluble material would get about 2/3 the result of applying the same rate of a 100% soluble material. Therefore, we should apply 33% more of the 5% soluble source to equal the 100% soluble source. However, the goal of fertilization is to get optimum growth response. Looking at the data in this way we see that in order to achieve more than 90% growth response, we have the roughly equivalent options shown in Figure 2.
+When first evaluating the data in Table 1, we could conclude that applying 10 lb./ac of a 5% soluble material would get about 2/3 the result of applying the same rate of a 100% soluble material. Therefore, we should apply 33% more of the 5% soluble source to equal the 100% soluble source. However, the goal of fertilization is to get optimum growth response. Looking at the data in this way we see that in order to achieve more than 90% growth response, we have the roughly equivalent options shown in Table 2.
-^  Figure 2 : Equivalent Effective Rates   ||||
+^  Table 2 : Equivalent Effective Rates   ||||
-^ Fertilizer Solubility ^ Application Rate (lbs/acre) ^ Effectiveness ^ Relative Value  |
+^  Fertilizer Solubility  ^  Application Rate (lbs/acre)  ^  Effectiveness  ^  Relative Value  |
-| 95% | 5.0 | **90.5%** | 100%  |
+|  95%  |  5.0  |  **90.5%**  |  100%  |
-| 70% | 10.0 | **90.6%** | 50%  |
+|  70%  |  10.0  |  **90.6%**  |  50%  |
-| 30% | 20.0 | **91.7%** | 25%  |
+|  30%  |  20.0  |  **91.7%**  |  25%  |
-Table 2 indicates that we should apply twice the amount of a 70% soluble material, and 4 times the amount of a 30% soluble material, to achieve the same goal as the 5.0 lb./A rate of the 95% soluble source. Based on this evaluation, the 95% soluble source is twice as effective as the 70% soluble source, and 4 times as effective as the 30% soluble source.
+Table 2 indicates that we should apply twice the amount of a 70% soluble material, and 4 times the amount of a 30% soluble material, to achieve the same goal as the 5.0 lb./ac rate of the 95% soluble source. Based on this evaluation, the 95% soluble source is twice as effective as the 70% soluble source, and 4 times as effective as the 30% soluble source.
-This relationship between solubility and effectiveness applies to other nutrients as well. In 1986, researchers at North Carolina State University, looking at manganese (Mn) sources used in row fertilizer, reported that "Manganese deficiency symptoms occurred with the least acid-forming starter fertilizer and decreased with increasing water solubility of the accompanying Mn materials.  Application of Mn materials with water solubility &amp;lt;100% would require proportionally higher rates of application of Mn to maintain Mn in the leaf.  The required Mn rate increases dramatically with decreasing water solubility of Mn material in the presence of a non-acid starter fertilizer." Stated simply, the higher the solubility of the Mn source, the better it worked. It also confirmed that Mn is more available in acidic conditions created by some formulations of row fertilizer.
+This relationship between solubility and effectiveness applies to other nutrients as well. In 1986, researchers at North Carolina State University, looking at manganese (Mn) sources used in row fertilizer, reported that "Manganese deficiency symptoms occurred with the least acid-forming starter fertilizer and decreased with increasing water solubility of the accompanying Mn materials.  Application of Mn materials with water solubility <100% would require proportionally higher rates of application of Mn to maintain Mn in the leaf.  The required Mn rate increases dramatically with decreasing water solubility of Mn material in the presence of a non-acid starter fertilizer." Stated simply, the higher the solubility of the Mn source, the better it worked. It also confirmed that Mn is more available in acidic conditions created by some formulations of row fertilizer.
-In "Micronutrients in Agriculture", Soil Science Society of America, Dr. John Mortvedt states that the " Use of granular oxysulfates with bulk blends will require that close attention be given to the level of water-soluble micronutrients in these by-products to ensure that sufficient amounts of micronutrients are immediately available to plants."
+In "Micronutrients in Agriculture", Soil Science Society of America, Dr. John Mortvedt states that the "Use of granular oxysulfates with bulk blends will require that close attention be given to the level of water-soluble micronutrients in these by-products to ensure that sufficient amounts of micronutrients are immediately available to plants."
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 Logic would dictate that the cost of micronutrient sources should be proportional to their effectiveness. However, this is not always the case. Where fertilizer supplier, consultants, or farmers must choose between various sources of micronutrients, one of the major factors in making that choice should be the solubility of each material. Low solubility materials may have some value in a long-term soil build up program, but when immediate results are the goal, highly soluble fertilizers are the best choice. **If the fertilizer producer cannot provide information on the solubility of their product, you can send a sample to Spectrum Analytic for that analysis. **
-!unlock