The Importance of Potassium (K) in Almonds
Potassium is major nutrient for almonds. It is involved in enzyme activation, photosynthesis, sugar translocation, protein synthesis, starch synthesis, and stomatal function. Approximately 76 pounds of potassium are removed per 1,000 pounds of kernel harvested. Nearly 70% of the harvested potassium is accumulated in almonds by mid-June. Potassium deficiencies can occur if potassium is not replaced and leaf potassium falls below 1% K. Potassium replacement should be initiated after harvest and continue through flowering in the following season. Traditionally potassium chloride, potassium sulfate, potassium thiosulfate, potassium nitrate, potassium carbonate, or potassium magnesium sulfate are used to replace removed potassium. Organic sources of potassium include greensand, langbeinite, manure, compost, potassium sulfate, mined rock powders, seaweed, sylvinite, and wood ash. There are some restrictions, as products may not undergo further processing or purification after mining or evaporation other than crushing or sieving. In California, approximately 50% of the typical potassium fertilizers are applied to almonds in May and June and 50% after Harvest (3).