Dealing with Drought and Dry Weather in the Field and Pasture

Last week, we discussed wet weather problems that could affect your operation. This week, we will discuss the opposite, drought and dry weather, and the effect that it can have on your fields and pastures. We will also take a look at a few mitigation tactics to help decrease the total damage a drought might cause.

Jump straight to each topic with the reference list below!

• Soil Moisture Deficits
• Wind Erosion Issues
• Forage Shortages and Grazing Damages

• Pest Pressure
• Livestock Diseases
• Water for Livestock and Irrigation

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A lack of moisture can lead to multiple problems for both fields and pastures. For plants, drought causes a reduction in photosynthesis as most plants stop or limit the exchange of gases necessary for photosynthesis to reduce total water loss (Water Stress in Plants).  When the lack of water goes on for too long, it can cause the plant to begin wilting and dying as its physiological processes get disrupted. Even if a plant survives,  long periods of soil moisture deficiency will lead to reduced yields.

For pastures, moisture deficiency causes a similar problem. In a weakened state due to severe soil moisture deficiency, forage lands may have a more difficult time recovering from a grazing period, requiring longer rest periods to recoup. Overgrazing and hoof traffic can become more difficult to control, as it takes less stress on the forage plants to cause lasting damage during long drought periods.

Mitigating weather-inflicted issues can be difficult, as the weather is impossible to predict perfectly. However, there are a few things that can help. One commonly suggested tactic is using blends of cover crops to build healthier soil and reduce water evaporation. Cover crops can also reduce water runoff, allowing more rain to soak into the earth when it gets it. However, cover crops that are not well managed can be detrimental to the following cash crop by absorbing too much of what little water there is. Having a good understanding of cover crop management can help alleviate potential issues, so if you want to employ this practice in your operation, make sure to do some research first!

Leaving plant residue in the field can also help maintain some moisture. The crop residue keeps the soil temperatures lowered, resulting in less evaporation. Additionally, it improves soil health. South Dakota State University Extension also suggests skipping tilling the soil if looking to preserve moisture, as tilling can expose the darker soil and moisture to the surface, where it evaporates the water more quickly.

The South Dakota Extension also suggests running a multiple crop rotation to help with water management. They suggest that multiple crops in rotation can improve soil health indicators like water storage and infiltration, which can help a field be more resistant to weather conditions.

For pastures, being more cautious with grazing time and patterns during dry seasons can go a long way toward preserving forage health. Shorter grazing periods can help prevent the buildup of too much hoof traffic damage and overgrazing. When it’s been dry for long periods, it is far easier to overgraze a pasture due to the reduced resiliency of the forage grasses. This makes maintaining proper pasture management an important tactic in keeping your pasture healthy so it can continue to produce (University of Wisconsin-Madison). 

Moisture is often a part of what helps keep soil particles bound together. During periods of drought, the soil is more easily detached from other particles. If this drier soil is exposed, strong winds are capable of carrying it away, eroding the field. Pastures that have had field cover killed by overgrazing or hoof traffic already are susceptible to wind erosion, which is exacerbated by the soil drying out and not sticking together as well (University of Nebraska-Lincoln Cropwatch).

Too much dry land with no ground cover can increase the chance for the phenomenon known as dust storms, where incredibly strong winds pick up soil and debris and toss it around. A lack of ground cover, such as crops and trees, can cause these dust storms to increase dramatically in intensity. A fantastic example is the recent dust storm that hit Chicago this May. Drier conditions with recently plowed fields combined with intense winds from a storm that blew through and took the field soil with it. The ensuing dust storm that swept through Chicago led to the skyline all but disappearing in the cloud of debris, which you can see in this time-lapse video from CBS. This prime example of dry weather, vulnerable soil, and strong winds eroded the nearby fields, dumping that soil in Chicago and beyond.

Again, the common mitigation tactic for wind erosion dry weather or not, is keeping the soil covered with something that keeps it from blowing away. Cover crops are a common option to keep the soil in place. While they won’t stop some dirt from naturally blowing away, it can keep a larger majority of the soil rooted in place. Even the attached residue from a terminated crop cover can help keep some soil in the field.

Windbreaks and other similar barriers are another effective tactic for reducing the amount of soil the wind can rip away. The downside is that it takes away some land that could be planted instead. The Nebraska-Lincoln Extension uses snowdrifts as an example of what can happen with barriers, as soil can often drift similarly, though not as rapidly.

Another option that can at least mitigate the damages is utilizing a center pivot irrigation system if it’s available. Irrigating dry soils reduces their chance of blowing by increasing the cohesion between soil particles with water.  This is not always an option, however, and if the soil dries out again, more water would have to be applied to maintain the effect.

Several effects increase pest pressures during a drought. Similar to wet conditions, some insects thrive in hotter and drier conditions than others. This can lead to pest insects that have more numbers with fewer predators, if their predators don’t do well in dry conditions. Additionally, with less moisture, fungi that would typically affect the insects do not grow as effectively, leaving even more insects to attack crops.

What makes it worse is that in long periods of dry weather, plants are already under extra stress from the soil moisture deficiency. Adding in pest insect attacks on top of the already worsened condition can cause severe problems for crops (Minnesota Crop News). Ron Hammond from Ohio State University gives a good example of how much the pressure can increase.

“Injury from insects can make problems even worse for crops already stressed under severe environmental conditions. Sometimes those thresholds need to be lowered to help protect the crop,” said Hammond. “A good example is the potato leafhopper on alfalfa.

The rule of thumb in determining potato leafhopper thresholds is, if out of a 10-sweep sample, the number of leafhoppers present is greater than plant height, treatment is warranted. Under hot, dry conditions, that threshold might be lowered by a third because plant development might not be as far along as it should be.”

Scouting crops remains an important tactic in protecting them from the potential of increased pest pressure. Knowing which pest insects you will be battling can be very helpful in selecting a treatment method. This will also allow for earlier applications of pest-fighting methods, which can increase their effectiveness.

Knowing your pesticides and how weather can affect them will also determine how effective any pesticide application will be. There are many different options, and some work better or worse in very hot, dry conditions. As an example, pesticides that require water to activate may become much less effective if the moisture level in the field is very low. It is also important to carefully consider what and when you spray, as it is possible to cause flare-ups of pest insects if you accidentally kill the beneficial insects that eat them (MSU Extension Field Crops).

Using strategies that increase the beneficial insect population can also mitigate some pest damage. The right predatory insects in an environment suitable to them can help keep pest insect numbers down significantly. This article from the University of Missouri Extension lists plenty of species that work as beneficial insects. The key is understanding the pests you fight, and encouraging beneficials that work well against them. Pesticides that harm beneficials could ruin this strategy though, so be cautious about what kinds of pesticides you plan to use if involving beneficial insects.

When plants are stressed from periods of drought, their growth rate is stunted, and their nutritional value is often lowered. This can lead to less production from livestock, and it becomes more difficult for a grazed pasture to recover from a grazing period. Livestock tend to enjoy higher-quality forage first before consuming other forage,  which leads to forage quality declining rapidly as the still healthy plants are rapidly depleted.

Additionally, as the cattle graze a field, their hoofs contribute to the damage the forage land sustains. Too much grazing and hoof traffic can lead to lasting damage to a pasture that can take a long time to recover. With soil moisture-deficient plants, that threshold is lowered even further.

A key factor in drought weather is reducing the amount of time livestock are allowed to graze any one pasture when possible. Giving the pastures more time to recover from a grazing period helps to ensure the pastures’ health in the future. Some managers suggest utilizing a small section of property as a “sacrifice” area if your pasture space is limited, which is used to allow animals outdoor access without destroying other pastures (Colorado State University Extension). 

Supplementing the forage with other feed sources may be necessary during extended drought periods. Prior planning and preparation can help ensure that animals have plenty of feed should a drought occur.  The National Drought Mitigation Center has several resources to help with planning and mitigation tactics.

During drought periods, it can become more difficult to maintain enough good-quality water for livestock. When water levels get low enough, it increases the potential for toxicity. Without an adequate water supply, livestock can be more susceptible to heat stress, which can further limit production or even lead to life-threatening conditions if bad enough. According to Miranda Meehan from North Dakota State University Extension, having enough safe water is critical for livestock.

“Providing adequate, safe water to livestock is critical for animal health and production,” she adds. “A 10% loss of body water is fatal to most species of domestic livestock. Water accounts for more than 98% of all molecules in the body and between 50% and 81% of an animal’s total body weight at maturity.”

The quality of the water can also be a problem during drought. As the water level decreases, it can increase the amount of bacteria, and leave behind higher levels of salts and minerals in what water is left. An Algal bloom is also possible, as the chance increases during droughts (University of Illinois Urbana-Champaign). If the quality is low enough, it can lead to severe illnesses in the livestock drinking from the water, or even death.

Different species of livestock generally require varying amounts of water for healthy production. Enabling animals to get the water they need when they need it is important in maintaining healthy livestock and production. Storing excess water during wetter times, digging deeper wells, and piping stored water to drinking troughs for livestock can all help keep water available for animals. The Oregon State University Extension also suggests utilizing areas where water is available, such as springs and seeps, or hauling in additional water when there are no other sources available.

Testing water quality in standing ponds and dugouts is also extremely important during a drought. Knowing what state water sources are in can help inform ranchers’ decisions on water management. If the quality of the stock pond has gone down, providing a different water source temporarily while treating the pond may help prevent problems from occurring for livestock (Testing Livestock Water Quality… – NDSU) .

There are several ways in which disease pressure can increase during a drought. To start, there are possibilities of increased bacteria or algae presence in water supplies as the total water amount gets lower. As mentioned in the section about watering livestock, this can cause several types of diseases or negative reactions. However, that is not the only place that increases the chance of diseases.

The West Virginia University Extension suggests that normal stress combined with prolonged dry seasons can increase the risk of several types of diseases in cattle. While there are several possibilities, one example the extension gives is EHD, or Epizootic Hemorrhagic Disease. According to the Extension, EHD is spread by a type of biting midge that has a higher chance of appearing during prolonged periods of drought. The University of Wyoming Extension mentions a few more disease possibilities, such as Polioencephalomalacia and BRSV.

For crops, drought weather will reduce the chance of some types of diseases that rely on plentiful moisture. However, Dry weather can weaken a plant to begin with, making it easier for other diseases to start an infection. Even if some diseases do not do as well in a dry environment, a weakened plant means sicknesses can cause more damage than they normally would (North Dakota State University).

Similar to the mitigation for water issues section, testing water supplies and removing or treating sections with problematic amounts of bacteria is a good way to protect livestock from many drought-related diseases. If the cattle cannot drink infested water, they cannot get sick. Making sure your livestock can maintain good nutrition can also help mitigate disease pressure. Good nutrition helps an animal to be healthier in general, and a healthy animal is more likely to fight off sickness. When there are long periods of drought, it may be necessary to supplement forage options with other feeds to help maintain healthy animals, as forage struggling with drought effects may not contain enough nutrients on its own.

Most tactics that help increase the general health of the crop during a drought can help it resist many of the diseases that can spread during dry weather. A healthier crop is much more capable of withstanding disease pressure if it’s not fighting drought stress too. Prevention is the key to fighting most crop diseases. Scouting is also important, and figuring out which disease plants are dealing with can help determine strategies for further mitigation.