Understanding the impact of drought on our crops is becoming increasingly essential in an era of changing climate conditions. This article aims to shed light on the damaging effects of drought on different crops, notably vegetables and arable crops, offering an in-depth understanding for growers worldwide.
Understanding Drought
Drought is a prolonged period of abnormally dry weather, leading to a severe water shortage. Droughts can be classified into four types: meteorological (low rainfall), hydrological (low water levels in rivers, lakes, and groundwater), agricultural (low soil moisture), and socioeconomic (reduced water supply). Each type poses unique challenges to crop growers.
How Drought Affects Crops
Photosynthesis
Photosynthesis is a crucial process through which plants convert sunlight into energy, and water plays a significant role in it. In times of drought, the reduction in water availability can slow or halt photosynthesis, inhibiting the plant’s growth and development.
Transpiration
Plants also rely on water for transpiration, a process similar to perspiration in humans. Transpiration helps in nutrient uptake and cooling the plant. However, in drought conditions, plants tend to limit transpiration to conserve water, affecting their overall health and growth.
Nutrient Uptake
Water is the medium through which plants absorb essential nutrients from the soil. A shortage of water limits a plant’s ability to take up these necessary nutrients, which can lead to nutrient deficiency symptoms and reduced crop yield.
Stress Responses
Extended periods of drought induce stress responses in plants. This can trigger premature ripening or wilting, or in extreme cases, it can cause plants to die off completely. Even if the plants survive the drought period, their yield and quality can be significantly compromised.
Soil Health
Prolonged drought can also lead to soil degradation, such as compaction and erosion, further impacting the growth and productivity of crops.
Effects of Drought on Vegetables
Potatoes
Potatoes, as root tubers, rely heavily on adequate moisture levels in the soil for their development. A lack of water in potatoes can lead to smaller tubers and reduced yield.
Also, severe drought can cause potatoes to develop irregular shapes and hollow centers – a condition known as “hollow heart“. Drought conditions can also stress the plants and make them more susceptible to diseases like common scab
Swedes
Swedes, also known as Rutabagas, are hardy vegetables that can withstand drier conditions better than many other crops. However, prolonged drought can still impact their growth.
Insufficient water during the development phase can lead to smaller, tougher swedes with a higher concentration of mustard oils, which gives them a stronger and more bitter flavor. Additionally, drought-stressed swedes may also be more susceptible to pest attacks and diseases
Tomatoes
Tomatoes are particularly susceptible to irregular watering patterns, and drought can lead to problems such as blossom-end rot.
This condition manifests as a dark, sunken spot at the blossom end of the fruit, typically due to a calcium deficiency that is exacerbated by inconsistent watering and subsequent drought.
Lettuce
Lettuce is a crop that requires regular watering, so periods of drought can be particularly damaging.
Insufficient water can cause lettuce to become bitter and bolt (i.e., go to seed) prematurely, resulting in a poor harvest. Extreme water stress can also lead to tip burn, which is the browning of the leaf edges [16].
Peppers
Peppers, like tomatoes, can suffer from blossom-end rot during a drought. They can also experience reduced size and yield. Peppers stressed by lack of water can become more susceptible to pests and diseases [17].
Cucumbers
Beans
Drought conditions can lead to poor pod and seed development in beans. Prolonged dry periods can result in lower yields and possibly total crop failure if the stress occurs during the flowering and pod-filling stages [19].
Effects of Drought on Arable Crops
Corn/ Maize
Corn/ Maize requires a lot of water, especially during the tasseling and silking stages. Drought stress during these critical periods can lead to barren ears due to poor pollination. Besides, drought can also cause the kernels to shrink and reduce in weight, significantly decreasing the yield.
Wheat
Wheat is relatively drought-resistant compared to other crops, but prolonged drought can still severely affect its yield and quality. Drought stress during the grain-filling stage can lead to shriveled grains and reduced protein content, impacting both yield and the quality of the grain [21].
Soybeans
Drought can be particularly damaging to soybeans during the flowering and pod development stages. Drought stress can lead to flower abortion, poor pod development, and reduced seed size, thereby significantly reducing yield. Soybeans under drought stress may also exhibit decreased nitrogen fixation, affecting the plant’s nutrient balance [22].
Rice
As a water-intensive crop, rice is severely impacted by drought. Drought during the tillering, flowering, or grain filling stages can lead to significant yield reductions. Drought-stressed rice plants can experience reduced photosynthesis, poor nutrient uptake, and increased susceptibility to pests and diseases.
The Importance of Water for Seed Germination
However, drought conditions can drastically impact this process. Lack of adequate water during seed germination can delay or inhibit germination altogether.
The seed may not absorb enough water to break dormancy, or if the seed coat does break and the emerging seedling is not supplied with enough water, the seedling may die before it can establish itself. Thus, even before a crop is visible above the ground, water plays a critical role in determining its success.
Summary
Understanding the effects of drought on crops is key to implementing effective mitigation strategies. With climate change increasing the prevalence and intensity of droughts, it is critical for growers to plan for such events and employ best practices to preserve crop health and productivity. Stay informed, stay prepared, and remember that the success of a crop can often hinge on how well it’s cared for in the face of adversity.
