From their thick, dark green, bumpy skin to their creamy and buttery flesh, avocados are among the most beloved fruits in the world. Indeed, they are increasingly taking pride of place in trendy, upscale restaurants and recipes everywhere. Avocados are incredible nutritious, containing healthy fats, vitamins, minerals and are packed with antioxidants, making them a favorite among the health conscious. But, how big are avocado tree roots, and how do they benefit the fruit and its consumer?
Avocado trees reach heights of up to 65 feet tall with a spread of up to 40 feet wide – and all this supported by an extensive system of roots. At the base of the avocado tree lie an interconnected web of both deep and shallow roots, with 15 percent of them grow horizontally and reach out up to 30 feet from the central tree trunk. The tap root of the avocado tree grows down to a depth of about 6 feet, but can reach a depth of 20 feet, depending on the soil type.
Avocado roots play a crucial role in providing stability and a steady supply of nutrients and water as the tree grows. The deep tap root takes advantage of deeper moisture reserves during dry periods, while the shallow lateral roots target surface moisture. These lateral roots can extend for several feet, enabling them to absorb more nutrients than the deeper roots. Humans can also benefit from the roots of the avocado tree, since they can help protect against soil erosion, and play a role in breaking up soil so that it better repels water and absorbs more oxygen when it rains.
Experts suggest that the extensive root systems of avocados also contribute to better quality and flavor of the fruit. Avocado fruits prefer a deep, fertile soil. As the roots turn over and loosen the earth, it improves the oxygen circulation and drainage in the soil, facilitating healthy root development and, ultimately, supplying the tree with essential minerals, trace elements and a balanced nutrient intake.
Severe drought has posed a real threat to avocados, as its shallow roots find it difficult to reach down to steady water supplies. Water shortages, accompanied by extreme heat, can be detrimental to the roots and can lead to reduced photosynthesis in foliage. This can lead to healthy, nutrient-rich leaves that are unable to provide the necessary sustenance to the tree and fruit, resulting in lower yields.
The avocado tree root system is an intricate and vital part of the tree. The tree needs an underground system that reaches further than just the 6 foot range. As avocados become increasingly popular, the avocado-growing industry has taken steps to ensure the roots are properly nurtured and cared for, so they can continue to provide the biochemical environment the tree requires to grow and bear the most nutritious avocados.
Beetles, Pests and Root Invasions
Another important factor that can affect the health of avocado tree roots is soil-borne pests and diseases. Various types of beetle larvae, weevils and worms can feed on the roots, leading to root rot, wilting, nutrient starvation and even collapse of the entire tree. When left untreated, these root-invading insects can destroy entire orchards. Therefore, regular inspections and prompt treatment of any infected trees is necessary.
Farmers take advantage of selectively cultivated avocado rootstocks in order to achieve greater soil fertility, improved tolerance to extremes in temperature, and increased resistance to pests, soil-borne diseases and invasive root systems. Avocado rootstocks also aid in soil drainage, allowing more water to reach the tree during extended periods of drought.
Rootstock also plays a part in controlling tree growth. The use of dwarf rootstocks helps to contain tree height and encourage flower growth, which, in turn, leads to greater yields of fruit. Furthermore, dwarf rootstocks enable farmers to contain the width of orchards and make it easier to manage crops, perform fertilization and pest control.
Soil Management Practices
In addition to rootstocks, some farmers also employ different soil management practices to increase the production and quality of avocados. Research has shown that soils can be managed by fertilization and/or mulching, both of which can act as effective supplements for avocados and improve root vigor and health. Mulching helps retain moisture in the soil, allowing the root system to uptake nutrients more efficiently, thereby improving the quality and quantity of the avocado yield.
Since different cultivars of avocados have varying soil conditions, soil management practices must be tailored to the specific needs of the cultivar in question. When selecting the fertilizer, it is important to use one that is especially suited to the selected cultivar and includes trace elements, such as magnesium, boron and zinc, that may be deficient in the soil. Fertilizers should be applied at the recommended rate, and only when the soil is moist enough to get the fertilizer deep into the root zone.
Finally, mulch plays a crucial role in soil management for avocado trees. Covering the soil and tree base with organic mulches not only help in retaining moisture, but also help to reduce weeds and protect the roots of the tree from extreme temperatures. Mulch should be applied about four inches thick, approximately a foot away from the trunk of the tree.
Irrigation Strategies
Since avocados are drought-tolerant trees, they require minimal irrigation. This makes it possible to use irrigation strategies that maintain adequate soil moisture while minimizing water use. A system such as drip or trickle irrigation, or even a regular spray system, can be implemented. These systems are known to reduce water usage while preserving the moisture and nutrient content of the soil.
Drip irrigation is the most efficient irrigation method. This type of system uses perforated plastic tubing or hoses with holes or nozzles along the length of the hose. Water goes directly into the root zone, reducing water waste and encouraging deep, abundant root systems. It also allows for more control over water distribution, which can benefit growers during times of drought or extreme heat.
Although avocado trees thrive in hot, arid climates, they do require some water during extremely dry periods. Deep, infrequent watering is sufficient for mature trees, but younger trees should be hydrated more frequently. This type of watering regimen allows the tree roots to grow deep and develop a greater absorptive capacity for water, which improves the tree’s ability to tolerate drought.
Root Pruning and Girdling
When dealing with an avocado tree’s root system, growers often resort to root pruning and girdling. Root pruning involves cutting through the tree’s roots to restrict growth and create a more balanced root-to-shoot ratio. Root pruning helps encourage a more robust and productive flowering and, ultimately, a higher quality of fruits. Girdling, on the other hand, involves cutting or removing the bark around the tree base in order to eliminate the tree’s root growth and encourage a stronger trunk.
Root pruning and girdling can be useful in controlling the size and spread of an avocado tree, as well as regulating its water uptake. When done carefully, these practices can help strengthen the tree’s roots and provide a better environment for the production of high-quality avocados. However, growers should exercise caution and be mindful to avoid over pruning or girdling, as this can cause severe damage to the tree and its roots.
Conclusion
The roots of an avocado tree are an essential part of the tree, providing stability and supplying the tree with the necessary water and nutrients it needs. Special care must be taken to ensure the root system stays healthy so the tree can keep producing nutritious avocados. By taking proper care and employing suitable rootstock, soil management practices and irrigation strategies, avocado tree roots can be cultivated to grow in the most optimal manner, while still providing the tree with enough stability.
