Introduction
Wildfire alters crop and water systems through changes in soil structure, infiltration, irrigation function and water availability. These changes can create substantial variability within and across fields, requiring careful evaluation of system performance.
Given the conditions surrounding recent fires, ongoing monitoring is essential to track recovery and support timely, adaptive management decisions.
Recovery Over Time
Days to Weeks
Following wildfire, burned ares are at increased risk for runoff, erosion, and reduced irrigation efficiency due to ash and sediment. Priority actions include reparing damaged infrastructure, implementing practices to improve soil conditions, and monitoring water delivery.
Weeks to Months
As the season progresses, management priorities shift toward monitoring crop water use, identifing severel burned areas and field variability, adjusting irrigation timing and application rates based on crop needs and conditions, and leaving soil covered to avoid runoff.
Cropwatch Display Link
Key Questions
Key Questions
When can I safely begin planting after a wildfire?
Planting should begin as soon as possible after a wildfire. Plant oils from burned residues can create water-repellent (hydrophobic) soils and surface crusting, which limit infiltration. Early planting, especially with cover or forage crops, can help break up the soil surface and allow for increased water infiltration.
Why does post-wildfire recovery require multiple steps over time?
Post-wildfire recovery is a process that requires different management actions as conditions change throughout the season. Early on, the focus is on rebuilding soil health so it can better absorb and retain water following wildfire, selecting crops with lower water demands where needed, and ensuring irrigation systems are inspected and fully functional before the season. Incorporate cover crops with appropriate species and timing to improve soil structure and infiltration, and use an irrigation scheduling tool to guide water application based on current soil moisture conditions.
As the season progresses, management shifts toward optimizing irrigation. This includes initiating irrigation early to replenish lost soil moisture, managing irrigation based on data-driven decisions to only irrigate when the crop needs water and identify the optimal rate, and ensure clean water from irrigation canalas as well as uniform water applications. Monitor areas with severe burn in the field to avoid crop wter stress by applying sufficient water. Use soil moisture tools and Crop ET and watether forecasts to guide decisions.
At the end of the season, the focus turns to maintaining soil cover and evaluating water use. Maintain soil cover to avoid runoff and regain soil health by drilling a cover crop. Retain crop multch or residue on the soil and consider not grazing it. Evalutate water budget and identify wherther there was idditional irrigation needed to plan for the following season.
How has wildfire changed my soil’s ability to absorb and hold water?
Wildfire reduces organic matter, leading to lower water-holding capacity, soil aggregation, and reduced infiltration. A thin hydrophobic layer can form at the surface as a result of oils from burned organic matter, causing water to run off rather than soak in and increasing erosion. Soil structure can degrade due to surface crusting and compaction resuliting from excessive drying under the high temperatures associated with wildfire.
What should I check in my irrigation system?
Wildfire can damage irrigation infrastructure both directly and indirectly. Producers should assess pivots, tires, electrical wiring, and well and feed panels for heat damage. In addition, sediment, ash, and debris pumped in from irrigation canals may clog nozzles or reduce water application uniformity. Assesement of all irrigation systems prior to growing season is critical to identify dimaged components.
How should I adjust my irrigation strategy after wildfire?
Reduced soil moisture at the time of fire, combined with lower infiltration and higher evaporation, can increase irrigation demand. Adjust irrigation strategy by initiating irrigation early in the season to replinsih lost soil moisture from wildfire and to ensure sufficient water for the crop without inducing water stress. Apply lower irrigation rates initially to account for surface crusting and hydrophobic conditions that limit infiltration and increase runoff risk. As soil structure recovers and infiltration improves over time, irrigation rates can be increased.
How can wildfire affect crop productivity?
Wildfire can reduce crop productivity in several ways. Remaining ash after wildfirec can be deposited on the plants, limiting photosynthetic activity. Additionally, crops may experience water streess due to legacy effects of post-wildfire water stress coupled with drought conditions.
What happened to the nutrients in my field?
Wildfire impacts to nutrients depend on where the nutrients were at the time of the fire. Dry fertilizer applied to the surface was likely lost due to fire or wind. Dry fertilizer incorporated into the soil will depend on the depth it was incorporated and how much topsoil was lost to wind. Fertilizer injected/knifed in is likely still present. Soil samples pre-plant or during the growing season will provide insight into actual nitrogen availabilty to the plant.
Nutrients from the residue were most likely lost to fire/wind. Specifically, residue nitrogen and sulfur were most likely lost to the air during the fire. Phosphorus and potassium from the residue would remain in the ash but only if the ash did not blow away.
- Wildfire damage and crop residue impacts
- Wildfire damage to crops FAQ
- Fire damage to unharvested crops and harvested ground
Are there ongoing efforts to monitor post-wildfire recovery?
UNL's Wildfire Monitoring Network has been developed to engage producers and help reduce uncertainty following wildfire.