|Plant Part and Time:||Upper mature leaves taken prior to or at bloom stage.|
|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. Excessive application of N fertilizer at planting may reduce the number of nodules and effectiveness of nodule bacteria. Low soil pH and other deficiencies can result in N deficiency; therefore, maintain the proper soil fertility level for optimum nitrogen fixation. Sidedressing with 50 pounds N per acre will normally correct N deficiency in a developing plant.
Less than sufficient due to low soil P test level and/or inadequate P fertilization. No corrective treatment is recommended for the sampled crop. For future crops, soil test and follow the soil test recommendation.
Less than sufficient due to low soil K test level and/or inadequate K fertilization. No corrective treatment is recommended for the sampled crop. For future crops, soil test and follow the soil test recommendation.
Less than sufficient due to low soil pH and/or low soil test Ca level. Soil test and apply gypsum according to current soil test recommendations. Application of gypsum is not generally necessary if the soil pH is maintained around 6.0 and the soil test Ca level on samples taken from the pegging zone (3-inches deep) 10-14 days after planting is 500 pounds Ca per acre or greater.
Less than sufficient due to low soil pH (less than 5.4) and/or low soil test Mg level. For corrective treatment, apply a foliar application of Mg, using 3-4 pounds of magnesium sulfate per acre in 20-30 gallons of water. Repeated applications may be necessary at 10-14 day intervals. For future crops, soil test prior to planting and follow soil test lime recommendations applying dolomitic limestone to correct soil acidity. If lime is not recommended, apply 25 pounds of elemental Mg per acre prior to planting.
Sulfur levels are usually maintained by fungicide and gypsum applications and deficiency is not likely to occur. No corrective treatment recommended for current crop.
Manganese deficiencies may occur on sandy soils with a pH greater than 6.3. If Mn deficiency occurs, apply a broadcast spray of Mn using 1/2 pound Mn per acre as manganese sulfate or 0.15 to 0.25 pound Mn per acre as chelated Mn in 20 gallons of water per acre. If symptoms persist, the spray should be repeated at 2 week intervals. In most cases, multiple applications will be required. High Mn levels are generally due to low soil pH. Manganese levels may be as high as 600-800 ppm before being toxic.
Deficiency is not likely to occur. High Fe test results normally indicate soil or dust contamination. An accurate Fe determination can only be obtained with washed leaves. (See section - Washing to Remove Contaminates)
Deficiency can occur on near neutral deep sandy soils, low in organic matter. Boron should be included in the fertilizer treatment. If the boron level is low, apply a foliar application using 1/2 pound of actual B per acre in 20-25 gallons of water. Boron applications should not be made after pod initiation as little benefit will be realized after this period.
Copper deficiency is not likely to occur as levels are generally greater than 5 ppm. When Cu base fungicides are used, the Cu values can be very high (100 ppm or better) for unwashed leaves.
Deficiency is not likely to occur except on high pH soils. Zinc levels above 60 ppm are excessive and zinc toxicity may occur on low pH soils when leaf Zn levels are above 110 ppm. A low level of leaf Ca is often associated with zinc toxicity in peanuts. Zinc toxicity may be more clearly identified by evaluating the Ca:Zn ratio in the leaf tissue. When the nutrient concentrations are converted to the same units (e.g. either % or ppm) a Ca:Zn ratio less than 45-50:1 is fairly indicative of zinc toxicity. NOTE: To convert ppm to %, move the decimal four (4) places to the left, e.g. 100 ppm = 0.1%.
Aluminum is not an essential element. When both Al and Fe test high, the leaves are probably soil or dust contaminated. (See Fe discussion above.)
Deficiency not likely to occur, although the Mo requirement is high compared to other crops for normal nodule function (see N section above). Molybdenum is not needed when the soil is properly limed.