Drought in Florida citrus is expected through June. Here is what you can do about it.

Florida has seen below average rainfall through the later part of March, and is likely to continue. The Seasonal Drought Outlook from the National Weather Service gives a forecast of “Drought Development Likely” for most of the citrus production regions in Florida through June.

Drought and heat waves often accompany each other and water and heat stress can have similar effects on crops. Water stress, however, can affect crops even in moderate temperature conditions.

Drought-stressed citrus leaves showing typical curling, as seen on Irrigating Citrus Trees article by Glenn C. Wright, College of Agriculture - University of Arizona (see article)

Water stress results in reduced turgor pressure which impacts several key processes in plants including cell division and enlargement. Water stress can lead to smaller leaves and fruit, thereby reducing crop yield and quality. Reduced photosynthesis is one of the first effects of water stress thus reducing the energy available to drive crop growth and yield.

Calcium promotes good root health and growth so the roots are better able to explore the soil to extract all the water that is in the soil. Roots that are calcium-deficient are shorter, thicker, with shortened, root hairs.

Roots with adequate calcium

Roots with insufficient calcium

Crops suffering from water stress are damaged by Reactive Oxygen Species (ROS) such as hydrogen peroxide (H₂O₂) and the oxide ion (O₂-) that form in response to stress. These ROS compounds damage plant membranes, proteins, and RNA and DNA. Calcium reduces the concentration and activity of these ROS compounds and thereby reduces the damage from water stress.

Soluble Ca and K mitigate drought stress

Humans sweat and the evaporation of water from skin cools us. Thus, our body temperature is 98°F when the air temperature on a hot day may be 108°F. In a similar manner, plant leaves transpire and the evaporation of water from the leaf cools the leaf. Leaves that are transpiring water are usually several degrees cooler than the air around them. Calcium, along with potassium, regulates the opening and closing of the guard cells around the stomates in leaves. Plants that lack sufficient Ca lose the ability to regulate the stomates and plants can become overheated.

Calcium also plays a second key role as part of the communication system in plant by signaling the water stress and triggering plant responses to water stress.

Calcium is required for the active transport of K across guard cell membranes in the stomata. This induces the opening/closing movement of the stomata regulating excessive water loss through transpiration during drought periods.

How you can provide the Ca and K your citrus crop need

• YaraTera NITRAKAL

YaraTera NITRAKAL 5-0-7 is a liquid fertilizer designed for fertigation derived from YaraLiva CN-9 and potassium nitrate. YaraTera NITRAKAL provides a balanced formulation of nitrogen, potassium and calcium that are immediately available for plant uptake. 

• YaraLiva Calcium Nitrate

How do you ensure that your crops have all the calcium they need to manage water stress? YaraLiva Calcium Nitrate is the ideal choice to provide your crop with calcium.

YaraLiva products have typically been used early in the spring to provide crops with readily available nitrate-N when soil and air temperatures are cool. However, the soluble calcium in YaraLiva fertilizers also plays a key role in helping crops overcome environmental stresses such as heat, water, salinity and sodicity. YaraLiva Calcium Nitrate needs to be part of your season-long fertilizer program in order to reach optimal yield and quality. 

YaraLiva Calcium Nitrates provide fast-acting nitrate-N, alongside strength-building calcium. In combination, these nutrients fuel prolonged growth. Plants and trees treated with YaraLiva calium nitrates are naturally healthier and less sensitive to stress during growth. Then, critically, in the build-up to harvest, YaraLiva calcium nitrate fertilizers improve the size, strength and appearance of harvested crops.

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