|Plant Part and Time:||Upper mature leaves taken prior to or at initial seed set.|
|Element and Sufficiency Range||Interpretation and Recommendations|
Low leaf N is primarily due to inadequate nodulation or ineffective nodules. Examine root system to determine extent of nodulation. At planting, the application of ammoniacal forms of N fertilizer may reduce the number of nodules and effectiveness of nodule bacteria. Low soil pH, other nutrient deficiencies and nematodes can also result in N deficiency; therefore maintain the proper soil fertility level for optimum N fixation. Sidedressing with 50 pounds N per acre will normally correct N deficiency for an already developing plant.
Less than sufficient due to low soil P test level and/or inadequate P fertilization. Soil test and follow the soil test recommendation. No corrective treatment recommended for the sampled crop.
Less than sufficient due to low soil K test level and/or inadequate K fertilization. Soil test and follow the soil test recommendation. No corrective treatment recommended for the sampled crop.
Less than sufficient due to low soil pH and/or low soil test Ca level. Soil test and lime as recommended. Soil pH should be maintained at approximately 6.0.
Less than sufficient due to low soil pH (generally less than 5.4) and/or low soil Mg. When Mg is low in the tissue (<0.25%), a foliar application of Mg may be effective in alleviating this problem. Apply at the rate of 0.30 to 0.40 pounds Mg per acre as magnesium sulfate in 25-30 gallons of water per acre. For future crops, soil test and apply limestone and fertilizer based on soil test recommendations.
Low S may occur on sandy soils where S-free fertilizers have been applied. No corrective treatment is recommended for current crop, however, for future crops, include a minimum of 10 pounds S per acre in the fertilizer.
Deficiency occurs when the soil pH is near neutral or above on very sandy soils or soils high in organic matter. When Mn deficiency occurs, apply a foliar application of Mn using 1.2 pound Mn per acre as manganese sulfate or 1/4 pound Mn per acre as MnEDTA in 10 to 20 gallons of water. If symptoms persist, apply a second application at the above rate. Manganese in excess of 200 ppm can cause yield reductions. Crinkle leaf may be observed when the leaf Mn level exceeds 500 ppm. Excessive Mn levels can usually be corrected by liming the soil to pH 6.0-6.5
Deficiency not likely to occur except on soils where the pH is greater than 7.0 and the soil sandy in texture and/or high in organic matter content. High Fe test results normally indicate soil or dust contamination. Aluminum will also be high. An accurate Fe determination can only be obtained with washed leaves. (See section - Washing to Remove Contaminates)
Deficiency likely to occur on near neutral deep sandy soils, low in organic matter. Soybeans are not particularly sensitive to boron and can develop normally even in low B soils.
Deficiency is not likely to occur.
Deficiency is not likely to occur, even on soils in which the soil test Zn level may be low. If low Zn is detected in the tissue, apply a foliar application of Zn using 1/2 to 1 pound Zn per acre as zinc sulfate or 1/4 to 1/2 pound Zn per acre as zinc chelate in 25-30 gallons of water per acre.
Aluminum is not an essential element. High Al test values indicate poor soil aeration due to soil compaction or poor drainage. When both Al and Fe test high, the leaves are probably soil or dust contaminated (See Fe discussion above).
Molybdenum has been found to be beneficial and is recommended as a seed treatment. It is doubtful that Mo would be sufficiently low to test below the sufficiency range in the leaf tissue on most Georgia soils that have been properly limed.