Zinc: Uptake can be decreased by high Phosphorus levels, liming or high levels of Copper, Iron or Manganese. Zinc deficiencies are often associated with Manganese deficiencies, especially in citrus.

Source: Growth and Mineral Nutrition of Field Crops, Third Edition. By Nand Kumar Fageria, Virupax C. Baligar, Charles Allan Jones, 2011. CRC Press, Taylor and Francis Group.

http://www.cropnutrition.com/efu-plant-analysis#diagnosis-of-nutrient-status