Phosphorus Improves Almond Tree Pollination

Principles of Almond Tree Pollination

Almond trees are almost entirely dependent on insect pollinators, especially bees. Unlike some fruit trees that can self-pollinate or rely on wind, almond trees require cross-pollination from different varieties. Most almond varieties are self-incompatible, meaning they cannot pollinate themselves and need pollen from another variety to produce nuts. This is why almond orchards often plant different varieties in alternating rows to ensure effective pollination.

The bloom period for almond trees starts very early in the spring, often when other plants are still dormant. This early blooming poses challenges in ensuring that bees are active and available for pollination. Cold or wet weather during this period can hinder bee activity and reduce pollination success. Commercial almond growers often place beehives in their plantations to ensure sufficient pollination during the bloom.

Bees visit almond flowers to collect nectar, and in the process, they transfer pollen from one flower to another, facilitating cross-pollination. This process is essential for the flowers to develop into almonds. Without bees, almond trees would produce very few nuts. Therefore, it is essential to attract as many bees to the almond trees as possible, and surprisingly, phosphorus can help here.

The Effect of Phosphorus on Almond Tree Pollination

Phosphorus (P) is one of the vital macronutrients and plays a crucial role in several metabolic processes within plants. One of these processes is phosphorylation, where a phosphate group is added to a molecule. This process is involved in the transfer of energy within the plant. A phosphate group is added to ADP (adenosine diphosphate) to form ATP (adenosine triphosphate) and store energy in a high-energy phosphate bond. ATP is the “energy currency” of plants. This energy is necessary for various growth processes, including the production and storage of starch in almond tree tissues. With more energy available, almond trees can accumulate more starch.

As the blooming period approaches, almond trees start to convert the stored starch into sugars needed for nectar production. This process is facilitated by phosphorus through the activation of enzymes. The more starch available, the more is broken down into sugars and used for nectar production. Increased nectar secretion makes the flowers more attractive to bees that are hungry after winter months. More frequent bee visits result in better pollination, leading to higher almond yields.

Advantages of Phosphorus Fertilization

For almond farmers, understanding the benefits of phosphorus fertilization is crucial. Phosphorus is not only important for the development of roots and the establishment of young trees but, as many studies have shown, regular P fertilization significantly boosts nectar secretion in almond flowers. This attracts more bees, leading to better pollination and ultimately increasing yields.

It is important to view almond tree fertilization in the context of modern farming methods that seek balanced nutrient applications, optimizing the physiological performance of a crop with economic efficiency and minimal environmental footprint. Phosphorus fertilization is a critical component of sustainable and profitable almond production.

Conclusion

Phosphorus fertilization is a powerful tool for almond tree farmers aiming to boost their yield. By enhancing nectar production, attracting bees, and improving pollination, phosphorus plays a pivotal role in almond tree productivity. Implementing optimal phosphorus fertilization practices can lead to a win-win situation for both the trees and the bees, resulting in abundant and delicious almonds.

The research presented in this article was conducted within a research project funded by The Center for Fertilization and Plant Nutrition (CFPN; www.cfpn.center). CFPN was established under a cooperation agreement between the Israeli Agricultural Research Organization (ARO; Volcani Center) and ICL.

Source:

Ranjith Karunakaran, Uri Yermiyahu, Arnon Dag, Or Sperling, Phosphorus fertilization induces nectar secretion for honeybee visitation and cross-pollination of almond trees, Journal of Experimental Botany, Volume 72, Issue 8, 2 April 2021, Pages 3307–3319, https://doi.org/10.1093/jxb/erab060