Orange Trees Irrigation – How to irrigate citrus trees
Efficient irrigation is crucial in orange orchards, particularly where water availability is limited. Proper irrigation practices directly impact the growth rate, yield, fruit size, and quality (juice content) of oranges. Understanding the specific water needs of orange trees can help growers optimize resources, enhance productivity, and protect against the damaging effects of water stress.
Orange tree water needs – How much water do orange trees need to grow and yield
Water availability could be a limiting factor for many citrus growers. When the orange orchard is established in sandy (light) soils, the problem is more significant due to the low water-holding capacity of the soil. As a result, many farmers choose to irrigate to satisfy plants' needs and support higher yields and premium fruit quality. Based on numerous research results, lemon and orange fruits' growth rate was doubled daily when the soil was wet, and even at temperatures of 100 °F (37 °C), compared to dry soil conditions.
Signs of Water Stress
Early indicators of water stress in orange trees include a dull green color and inward curling of the leaves. Persistent water deficiency may cause leaves to lose flexibility, become brittle, and dry (die) from the tips. In severe cases, growers may observe leaf drop and, depending on the season, flower and fruit drop as well.
Scheduling Orange Tree Irrigation for Optimal Growth
Certain growth stages require more consistent irrigation to support fruit development and prevent crop loss. Key periods to maintain adequate soil moisture include:
- Flowering (Spring): Water stress during flowering can severely reduce production, so it is common to irrigate a few days before flower initiation to support bud formation.
- Post-Fruit Set: At the early stages of the fruit set, keeping the soil moist is critical to ensure proper fruit growth and prevent premature fruit drop.
- Fruit Maturation: Consistent irrigation during fruit ripening helps improve fruit quality and juice content.
Factors Influencing Water Needs of Orange Trees
The amount of water required will depend on tree age and size, planting density, soil type, climatic conditions, and rainfall. On average, orange trees require approximately 60 inches (1524 mm) of water annually. In peak dry periods, mature trees may need as much as 17 gallons (64 liters) of water per day (per tree) to maintain optimal growth.
One approach to accurately determine water requirements is to calculate the daily evapotranspiration (ET) rate using data from local weather stations or soil moisture sensors. Multiply the ET value by the crop coefficient (Kc) to estimate daily water loss. A helpful formula to calculate daily water use is:
Daily water use (L) = Evaporation (mm) x 0.7 x Canopy ground area (m²)
Key Irrigation Principles
There are 3 major rules-principles when irrigating orange trees.
- We need to water the soil to keep it moist close to the active root zone (30-40 cm or 12-16 in) (but not soggy) around the root zone at all times. The orange trees' water uptake decreases as the soil dries. For example, an orange tree can absorb less than half as much water when the available soil water content is around 50%. However, allowing the top 6 inches (15 cm) of soil to dry between irrigations is essential to limit the risk of soil-born diseases.
- Young trees need more frequent irrigation than mature trees do (mainly due to accelerated growth and shallow and underdeveloped root system). Especially during the planting and establishment period, irrigation with sufficient water (5-10 liters per tree per irrigation session) is needed.
- Sandy soils require more frequent watering than heavier clay soils because they drain water quickly. Trees in sandy soils may need up to three times more water than those planted in clay (heavier soils).
However, these are rules of thumb that give a general direction. Every orange farm is different, with distinct characteristics (soil type, plant density, etc). Orange farmers are advised to do their own research and seek advise from local agronomists to optimize the quantity of water supplied to the orange trees per case.
Applying organic mulch, such as leaves, wood chips, or bark, around the base of the tree (without direct contact with the trunk) can help retain soil moisture, reduce evaporation, and suppress weed growth.
Choosing the Best Irrigation System for Orange Orchards
How to irrigate your orange orchard
Various irrigation methods can be employed in orange orchards, each with specific advantages and considerations. The grower should carefully examine all the available choices and select the most suitable based on numerous factors, such as water availability and quality, soil type, initial available investment, environmental conditions, etc.
Flooding and Basin Irrigation: This traditional method involves flooding double circular basins around the tree trunk. While water-intensive, the full cover irrigation system (surface irrigation) allows the farmer to establish a cover crop among the tree lines.
Micro-Sprinklers: According to the American Society for Horticultural Studies, water conservation efforts and frost protection measures have been major impetus for converting irrigation delivery systems from overhead sprinklers to micro-sprinklers over the last 30 years. Micro-sprinklers deliver water efficiently, using 30–50% less water than full-cover or surface irrigation.
Micro-sprinkler systems have lower initial establishment costs than solid-set sprinkler systems for widely spaced tree crops. Low-volume micro-sprinkler systems provide a greater degree of frost protection than conventional sprinklers. Moreover, using micro-sprinklers, fertilizer, and other chemical applications can be more timely, uniform, and cost-efficient.
Drip Irrigation: Drip irrigation systems have become increasingly popular in the past few years for irrigating orange and citrus trees, especially in young and newly planted orchards. If the orange grower wants to switch from another irrigation system to drippers, he/she should consider the sensitivity of the variety cultivated to this change. For example, sweet oranges do not react very well. Fertigation is also facilitated when a drip irrigation system is used.
Farmers sometimes choose to install two different irrigation systems (sprinkler system and drippers) in their citrus groves to take advantage of both.
References
https://edis.ifas.ufl.edu/publication/ss676
https://edis.ifas.ufl.edu/publication/CG093
https://cals.arizona.edu/extension/ornamentalhort/landscapemgmt/general/citrusirrigation.pdf
https://nhb.gov.in/pdf/fruits/citrus/cit006.pdf
http://horttech.ashspublications.org/content/20/1/74.full
https://www.agric.wa.gov.au/water-management/citrus-irrigation-recommendations-western-australia
https://journals.ashs.org/horttech/view/journals/horttech/20/1/article-p74.xml?rskey=oK6NAB&result=10
1.) Orange Tree Information & Uses
3.) How to grow Orange Trees from seed
4.) How to grow an Orange Tree from cuttings
5.) Growing Orange Trees for Profit
6.) Orange Tree Climate & Soil Requirements
7.) Choosing Orange Tree variety
8.) Orange Tree Propagation & Pollination
10.) Orange Tree Fertilizer Requirements
11.) Orange Tree Water Requirements
13.) Orange Tree Harvest & Yields
