Guide to Drought Management for NH Growers

With sporadic rainfall and abnormally dry conditions affecting various parts of the state, many may be currently facing summer drought stress on your farms. The following article summarizes the potential impacts of drought on fruit, vegetables, and row crops, along with a number of proactive management strategies to help mitigate these effects. 

Understanding Drought's Impact on Your Crops:

Drought is not just about a lack of water; it is about the stress it puts on your plants and livestock.

1. Yield and quality: For fruits and vegetables, drought stress can lead to smaller and/or cracked fruit, reduced yields, and lower overall quality. Plants may drop leaves, flowers and fruit to conserve water. For row crops like corn and hay, the lack of moisture stunts growth and causes corn ears to lose kernels or reduces kernel fill resulting in lower tonnage.
2. Physiological stress: When plants cannot access enough water, they become more vulnerable to pests and diseases. They also shut down key processes like photosynthesis, which is critical for growth and ripening.
3. Nitrate accumulation in forages: A serious concern for growers with livestock is the buildup of nitrates in drought-stressed corn and hay. Under dry conditions, plants absorb nitrogen but cannot convert it into protein, leading to potentially dangerous concentration. Consuming this forage can be toxic to livestock, particularly cattle, and can even be fatal.
4. Wilting for short periods of time may not hurt plants: Sustained periods of drought can lead to damage such as scorched leaves or browning and aborting of flowers.

Proactive Strategies for Managing Drought:

While we cannot control the weather, you can implement a variety of measures to protect your crops and manage risk.

1. Optimize water use and soil health
   1. Efficient irrigation: Switch to drip irrigation or soaker hoses to deliver water directly to the plant's root zone, minimizing evaporation and waste. Water less frequently and more deeply.
      - Use soil moisture sensors to accurately determine when irrigation needs are met, and when irrigation is needed. Lear more about using sensors on your farm here: Soil Moisture Sensors [fact sheet]
   2. Soil health: Improve your soil's water-holding capacity by increasing its organic matter content. Use cover crops, compost, and reduced-tillage practices to create a healthier, more resilient soil that acts like a sponge. Poor soil structure leads to soil compaction early in the season, which can inhibit root development, thus attributing to moisture stress later in the season.
   3. Mulching: For vegetable and fruit crops, applying a layer of mulch around plants helps retain soil moisture, keeps roots cool, and suppresses weeds that compete for water.
2. Fertilization, growth regulators, and forage safety
   1. Avoid excess fertilizer: It may be tempting to fertilize a struggling crop, but do not apply excessive nitrogen to drought-stressed corn or hay. This can increase the risk of nitrate accumulation and poisoning in livestock.
      - Additionally, in drought conditions, one must be particularly cautious with fertilizer application and fertigation (applying fertilizer through irrigation systems). The lack of rainfall and soil moisture can lead to a buildup of soluble salts from fertilizers in the root zone. This concentration of salts can cause salt injury, which damages roots and inhibits the plant's ability to absorb water, making the effects of drought even worse. Symptoms of salt injury include leaf tip burn, stunted growth, and wilting.
   2. Use of Growth Regulators: Application of cytokinins, ABA, and brassinosteroids to promote root growth and reduce transpiration rates, thereby enhancing drought resistance.
   3. Test forage: If you plan to harvest drought-stressed hay or corn, test it for nitrate levels before feeding it to livestock. Many university extension services and labs offer this service, and it is a critical step in protecting your animals.
   4. Strategic harvesting: For hay that may be high in nitrates, consider raising your cutting height, as the lower part of the plant contains the highest concentration. Ensiling corn can reduce nitrate levels by about 50%, but you should still test the silage.
3. Stay Informed and Seek Assistance
   1. Monitor conditions: Keep an eye on the U.S. Drought Monitor for updates on local conditions. Stay in touch with the NHDES and your local UNH Cooperative Extension office for guidance.
   2. Submit a water stress observer report to your local extension educator or to the National Drought Mitigation Center (NDMC) https://www.drought.gov/data-maps-tools/condition-monitoring-observer-reports-drought-cmor-drought
   3. Emergency programs: Be aware of federal and state assistance programs from the USDA's Farm Service Agency that can provide financial and technical support to farmers impacted by drought.

By implementing these strategies, you can minimize the impacts of the current drought, protect your crops and livestock, and build long-term resilience on your farm.