Cultivos vulnerables ante las heladas y sequía: ¿Cómo minimizar las afectaciones en la agricultura?

Crops vulnerable to frost and drought: How to minimize the impact on agriculture?

In northern and central Mexico, especially during the cold months (November-February), temperatures can drop below 0°C due to the flow of dry continental polar air from the United States. The movement of the large polar masses from north to south in late autumn in the country is responsible for the most intense frosts. The damage caused to crops depends on several factors, such as the sensitivity of the species or variety, the development phase of the plant, the intensity and duration of the frost, and the geographic location of the crop, among others.

Image 1. Frost present in the current storm.

Low temperatures in crops can cause damage to plants (cold and freezing), but the mechanisms and types of damage vary considerably. Fruit, vegetable and ornamental crops of tropical origin are especially those that suffer the most noticeable physiological damage when they are subjected to temperatures below +12.5°, which is freezing temperature. An example of the most affected would be: onion, lettuce, pepper, cherry, cucumber, apple, pear, citrus and other stone fruits. On the other hand, above 0°C it is more due to cooling than frost. However, crops grown in cold climates survive with little damage when freezing is not very severe, such as crops such as: chard, broccoli, parsley, tomato, artichoke, cauliflower, beans, grapes, garlic, asparagus, carrot and broad beans.

Cold thermal stress appears between 15° and 0°C, and below 0°C it usually produces ice crystals inside the cells (intracellular) of the plants causing “cell death”, this can result in wilting, discoloration and death of plant tissues, this is called “black frost”. While “white frost” (derived from dew) causes less damage than black frost since freezing only occurs on the outside of the plants. Also, when the temperature is below 10°, its growth is no longer optimal, causing an internal water deficit in the plant cells and obtaining poor quality harvested products. In addition, frost can affect the reproductive organs of plants, such as flowers and fruits, reducing their production and making them more susceptible to various fungal and bacterial diseases.

Table 1. Maximum crop temperatures before reaching freezing (black frost).

Frost damage to crops, resulting in poor quality produce, decreased yields, extra costs for disease control and soil rehabilitation, creates significant financial hardship for farmers. In addition, damaged crops can lead to the loss of potential income, negatively affecting farmers' overall profitability.

Image 1. Comparison between white frost (top) and black frost (bottom). Both cause stress in the plant, but black frost causes tissue necrosis and is more severe.

How does it affect the soil?

Frost also has a negative impact on soil, as freezing can cause soil to expand and contract, leading to soil compaction and reduced aeration, hampering root growth and nutrient uptake, affecting crop development, and altering soil microbial activity and nutrient cycling processes.

Protective measures

  • One way to protect your crop from frost is by using covers or shelters made primarily of fabric or plastic. These create a greenhouse-like environment, trapping heat and preventing frost formation. Also, using mulch around the base of plants can help insulate the soil and conserve heat.
  • Proper site selection is important to prevent frost damage. Avoiding low areas where cold air collects and choosing sites with good air circulation helps reduce the risk. Planting on slopes also allows cold air to move away from plants, reducing the impact of frost.
  • Selecting crop varieties that have a greater tolerance to low temperatures (chard, broccoli, parsley, tomatoes, cauliflower, broad beans, etc.) helps reduce frost damage, since some crops are naturally frost-resistant and others were bred to be resistant to cold climates.
  • Using sprinklers above and below the plants, micro-sprinklers, overhead irrigation and artificial fog reduce the energy of frost. Strategically placed solid, liquid or gas fuel heaters also help and should run continuously for at least eight hours.
  • Growth regulators and soluble concentrates applied systemically before frost help to increase the concentration of solutes in the plant and the use of biostimulants as a bioprotector for the plant .

  • Using anti-frost nets protects against frosts of up to -5°C and also protects against wind, heavy rain, hail and pests. In addition, it is important to keep in mind that no method is 100% effective against severe frosts.
  • Use technological equipment and platforms that can help predict frost in real time.

Table 2. Fruits and vegetables most susceptible to frost damage.

Some plants, such as C4 plants (palms, tomatoes, etc.), have little ability to harden against cold. Hardening involves mechanisms of frost avoidance and tolerance, such as the accumulation of sugars that lower the freezing temperature of tissues. However, hardening is rapidly lost after warm days, although fruit buds can harden again, but at a slower rate. To prevent the loss of hardening, crops are cooled with sprinklers during warm periods of the day.

Protecting crops from frost requires preventive and creative approaches. Farmer training and access to weather information are essential for frost-resilient agriculture. Creativity in applying these strategies is essential to ensure success in protecting crops. In addition, it is important to understand the connection between frost and drought in crops, thus comprehensively addressing climate challenges in agriculture.

How are frosts related to drought in crops?

The relationship between cold and drought in crops is not usually very obvious at first glance, since drought is related to a lack of water, while cold is related to low temperatures. However, there are some aspects in which cold can influence drought, such as:

  1. Extreme weather events: In some areas, cold conditions are often associated with weather patterns that block the arrival of wet fronts, thus contributing to drought.
  2. Dry winters: These can cause an initial lack of water, affecting availability during the crop growing season.
  3. Late frosts: These can damage young plants, compromising their resistance to subsequent dry conditions.
  4. Climate change: These can alter weather patterns, contributing to droughts throughout the year.

Mexico is currently in the midst of an agricultural crisis marked by the loss of the largest number of hectares of crops since at least 2018, due to prolonged drought. From January to September 2023, the country experienced a record 502,550.14 hectares that did not complete the germination process, representing an increase of 679.4% compared to the previous year, according to data from the Agri-Food and Fisheries Information Service (SIAP).

The most affected states are Chihuahua, Zacatecas and San Luis Potosí, which together account for a total of 411,587.55 hectares lost, with the shortage of water for irrigation being one of the main causes behind these losses. The most affected crops are: beans, grain corn, green forage oats, green forage corn and grain sorghum. These crops are a crucial part of food production in Mexico. In particular, beans suffered a loss of 165,715.80 hectares affected this year, which could have a significant impact on the prices of the country's basic food basket.

Image 2. Among crops, there are some that are more resistant to low temperatures, including lettuce, berries, etc.

The decrease in rainfall this year is partly due to climate change and the “La Niña” phenomenon. The shortage of water for irrigation, identified as one of the main causes of losses, is closely linked to both drought and frost. These can aggravate the situation by affecting the germination capacity of crops, making plantations already affected by the lack of water vulnerable.

The phenomenon of climate change is a topic that has been studied for decades due to the obvious changes in weather patterns caused by global warming and the greenhouse effect. This brings consequences such as frosts and droughts that affect producers and their crops, so it is crucial to address these challenges and find ways to implement adaptation and mitigation strategies to strengthen the resilience of agriculture to climatic events.

What do you think are the most creative and effective measures that farmers can implement to protect their crops from extreme cold and ensure food security in the community? Share your ideas with us.
Article, visit website: (24) Crops vulnerable to frost and drought: how to minimize the impact on agriculture? | LinkedIn

References:

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.