|Plant Part and Time:||Healthy mid-terminal leaves on current season's growth taken in mid season.|
|Element and Sufficiency Range||Interpretation and Recommendations|
Deficiency due to inadequate N fertilization and/or ineffective N fertilization. If the leaf N level is less than 1.80%, for next year's crop, apply 0.3 to 0.6 pounds of N per tree. If this year's terminal growth was less than 8 inches on trees that set a good crop, use the higher N rate; if terminal growth was 8 inches or more, lower the N rate. Where vigor is low, nitrogen can also be supplied by spraying low biuret urea at 6 to 12 pounds per acre after bloom but not in late cover sprays. If the N level is greater than 1.80%, for next year's crop, apply 0 to 0.6 pounds N per tree. If this year's terminal growth was less than 8 inches on trees that set a good crop, use the higher N rate; if terminal growth was 8 inches or more, lower the N rate accordingly. If terminal growth was more than 15 inches, do not apply any nitrogen.
Phosphorus deficiency is rare in pear trees under field conditions. Low phosphorus is generally due to very low soil test P levels and low soil pH. Phosphorus should be adequate if the soil test P level is maintained at medium or higher levels and the pH maintained between 6.0 and 6.5. If the leaf P level is low and the soil test P level is low or medium, apply 60 to 30 pounds P2O5 per acre. If the soil test P level is high, do not apply any phosphorus fertilizer.
Low K levels are generally due to low soil test K. If the leaf level is low, and soil test K level is low or medium, apply 60 pounds K2O per acre. If the soil test K level is high, do not apply any potassium fertilizer. If the K content is within the sufficiency range, no additional potassium fertilizer will be required for the next crop, irrespective of the soil test K level.
Deficiency not likely to occur under normal orchard conditions. Less than sufficient level due to very low soil pH and low soil test Ca level. Soil test and lime to adjust the soil pH to 6.0 to 6.5.
Deficiency due to low soil test Mg and/or low soil pH. Soil test and lime using dolomitic limestone. If soil test Mg level is low, the use of SUL-PO-MAG or K-Mag to meet the K requirement is desirable. However, pear is not considered a Mg sensitive crop; therefore, proper maintenance of soil pH using dolomitic limestone should be sufficient to meet the Mg needs.
Deficiency is not a common problem, but excessive Mn (>200 ppm) is sometimes encountered. Excessive Mn levels are generally observed in pears when grown on low pH soils (<5.5). Soil test and lime to pH 6.0 to 6.5.
Deficiency not a problem in Georgia. High Fe test results normally indicate soil or dust contamination. An accurate Fe determination can only be obtained when the leaves are properly washed (See section - Washing to Remove Contaminates).
Boron deficiency causes fruit pitting, blossom blast, and spur die-back. Deficiencies of B can be corrected by soil application of 2 pounds of actual B per acre once every 3 to 5 years, or annual foliar applications using 0.4 to 0.8 pounds of actual B per acre in sufficient water to completely wet the foliage.
Deficiency not likely to occur. Copper deficiency results in die-back and a disease of pear known as exanthema. Deficiencies can be alleviated by soil applications of 1/2 to 2 pounds of copper sulfate per tree.
Little-leaf, rosette and leaf mottle are associated with low leaf Zn concentrations. For corrective treatment, apply a foliar application of Zn in mid-October using 1 pound of actual Zn (3 pounds of zinc sulfate per acre in 100 or more gallons of water) per acre.
High Al levels are not likely to occur. When both high Fe and Al values are obtained, they are probably due to soil or dust contamination. See Fe discussion above.
Sufficiency range is not firmly established for pear trees.