Rainfall in the west is acidic, mildly. The pH of rainfall tends to be around 5.4 to 5.6 in the Central Valley of California. While the rainfall is critical for crop growth and development, the acidic nature of winter rains can leach positively charged mineral ions in the soil. The pH scale represents an increase in hydrogen ion concentration on the acidic side (<7.0) and an increase in hydroxyl ion concentration on the basic side (>7). On the soil colloid surface where mineral ions are exchanged into the soil solution, the positively charged hydrogen ions from rainfall can displace and with the help of gravitational water movement, leach essential minerals such as zinc, potassium, and calcium thereby reducing the availability of these nutrients early in the spring.
After bloom, significant growth occurs in the developing nuts, in the canopy of the tree, and in the roots below the surface. Though the perennial tissues of the tree should have storage of critical nutrients required during bloom, those nutrients will become limiting very quickly following leaf out.
Nitrate-nitrogen is taken up rapidly and can aid in uptake of positively charged ions like zinc, potassium, and calcium. Zinc activates enzymes which play a role in cell enlargement and is also critical in chlorophyll formation. These roles are evident at early leaf out when deficient leaves emerge small and pale in color. Additionally, zinc is essential for the formation of auxins which regulate internode elongation and balanced growth. Potassium is involved in critical development and maintenance roles in almonds. Transport of sugars, starch formation, and stomatal regulation are all key roles of potassium. Spur survival and productivity are directly affected by tree potassium status. The solubility of calcium is key in this early development. Soluble and available calcium encourage optimum pollen tube growth. Soluble calcium promotes cell wall integrity in developing nuts and to promote root health below the surface.
Almond nut set is like getting a haircut, you can always take more off, but you can’t put it back on. Set your best crop by being mindful of critical demand periods for specific elements and by taking a proactive approach.
4-15-0 12.5% Ca, 3.7% Mn, 2.5% Zn, 1.2% B
Yara’s Solutions sheets are a series of technical, multi-product, advisory documents that are strategically focused on nutrition for crop-specific phenology and physiology. As each piece is launched, we will share digitally through the MyAlmond newsletter network.
Consult your Yara Agronomist for custom-tailored recommendations and comprehensive crop nutrition support.
With 40 acres of fertigated and established almonds, and 40 acres of irrigated and established walnuts, the Yara Incubator Farm in Modesto, California is a center for research, solution trials and knowledge sharing.