4 tips for preventing sunburn in your citrus crop
Citrus production can be significantly impacted during summertime heat. Environmental conditions play an essential role in determining the quantity and quality of fruit yield. Elevated temperatures combined with drought and excessive sunlight can affect the growth and productivity of citrus trees.
Without timely management, citrus trees can experience leaf bleaching and yellowing, growth decline, reduced flowering and fruit setting, increased fruit drop and fruit sunburn. The damage caused by high temperatures and water deficiency also decreases fruit quality by affecting fruit maturity, skin quality and color, while also increasing fruit cracking and creasing. Growers looking to maintain citrus orchard productivity in the face of high-temperature summers can implement management strategies to help citrus trees overcome heat stress.
Irrigation management and scheduling
One of the most important elements for mitigating heat stress is irrigation management. Any time a plant is water stressed, its growth is reduced. Keeping citrus trees adequately irrigated through heat events allows trees to lower their temperature by regulating their internal water. Trees may also photosynthetically shut down under heat stress, which can result in lower yields and excessive fruit drop. To help citrus tress tolerate midday high temperatures, irrigate early in the morning or during the evening to reduce evaporation loss. It’s recommended to water newly planted trees consistently and more frequently due to their lack of established root system. Implementing a sprinkler or drip system is one way to ensure consistent watering.
Control soil salinity
Citrus trees are sensitive to salinity. It is recommended to consider the salinity factor in the irrigation water and in the root zone as part of a good irrigation management strategy. Salty soils can reduce citrus growth and cause physiological disorders by limiting water and mineral uptake, increasing water stress. Salt can be moved from the root zone through the process of leaching, which is a slow and steady application of deep watering over a long period of time. Drip or microsprinkler systems can also be used to leach salts when used for an extended period of time.
Trees that suffer from nutrient deficiency may be more susceptible to heat stress. Citrus trees have high nutritional requirements during the flowering, fruiting and growth stages. If nutrient requirements are insufficient, high temperatures may lead to increased respiration and decreased photosynthesis, which causes nutritional imbalance and leads to flower and fruit drop. Ensuring citrus trees have optimum nutrients with a consistent fertilization plan throughout the entire year will help trees better manage heat stress.
Plant surface protection
Heat stress and sunburn can take a toll on citrus orchard productivity. Cuticle supplements used in a planned treatment program can significantly reduce losses from sunburn and heat stress. When applied before severe summer conditions and maintained throughout the hot months, cuticle supplements can increase fruit quality, plant health and marketable yields.
The use of foliar applied cuticle supplements provides sunburn protection and improved stress tolerance by increasing the plant’s antioxidant capacity and increasing key components that allow the plant to use excess light energy for photosynthesis, preventing photo-oxidation that causes sunburn damage. Applications of a cuticle supplement also result in better overall tree performance and less fruit drop by increasing net CO2 exchange and transpiration rate. As a result, treated citrus trees are better equipped to sustain growth under environmental stress to deliver high-quality fruit and marketable yields.
While the heat of summer can leave its mark on citrus trees, implementing proactive management strategies and protecting the fruit cuticle can help citrus orchards tolerate high temperatures. Talk to your Cultiva representative today to learn how you can maximize production and quality of citrus fruit during heat waves.