Optimizing Crop Health in Dry Field Conditions

Do dry field conditions, cool temperatures, or slow emergence have you revisiting your 2021 crop protection and nutrient management plans? Angie Rieck-Hinz, ISU Extension Field Agronomist, shares agronomic best practices for optimizing crop health in dry field conditions.

Although corn and soybean planting progress is ahead of the five-year average, soil moisture deficits persist across much of the Corn Belt and northern IA. According to the Midwest Climate Hub and NASS, most areas ahead in progress were planted into dry soils and are experiencing slower emergence due to drier, cooler conditions. 

Crop Health Optimization in Drought Conditions

Not only do drought conditions limit water supply to crops, consequently, less water also means less nutrient uptake. “The lack of water in the soil can impact overall growth and development of crops, along with yield and quality of the grain,” states Angie. “Loss of yield is highly dependent on timing (growth stage), length, or duration of the dry conditions and severity of the stress (if complicated by heat).”

Adaptability

“As in any year, adaptability is key,” emphasizes Angie. Despite being early in the growing season, Angie anticipates crop disease pressure to remain low if the weather pattern stays dry this year. For example, perhaps a standard plan may include a fungicide application, but it may not be needed in a dry year. “Scouting fields allows flexibility to cut back on inputs if they are not needed,” states Angie. “Similarly, scouting is a tool to help determine where to reallocate input dollars, if needed, as the growing season progresses,” Angie adds. 

Input Productivity

With early season dry conditions, activation and efficacy of pre-emergence herbicides may be compromised. It usually takes about a half-inch of rain to activate herbicides and move them into the soil. If soils are unusually dry, it may take more than half an inch of rain to wet the ground and move the herbicide. If fields fail to receive an activating rain with 5-7 days or application, alternative methods to early season weed control, such as a rotary hoe, may be needed. If this is not possible, scouting fields will be more critical if rainfall continues to be limited. Scouting within two weeks of planting will help determine the appropriate timing for post-emerge herbicide applications. (ICM, Hartzler, 2021

Yield Productivity

Are you considering adjusting nutrient rates or forms of application this season? Minimize loss with these agronomic tips. 

Corn growth requires water for respiration, development, and nutrient flow to roots. If the upper part of the soil profile stays dry, corn roots will often proliferate at deeper depths. “If moisture is limited, nutrient uptake will be limited, thus adding more nutrients (above planned total rates) will not contribute to yield,” states Angie. “If additional nutrients are needed in such conditions, primarily an addition of N, one must consider how a lack of rain might impact N movement into the soil if N is surface applied.” Angie adds that injected N will minimize volatile losses. 

Prioritizing Nutrient Management Plans

When considering making changes to application plans, do research first to determine where the priorities lie. Then, before making any decisions, Angie suggests consulting your most recent soil test to determine P and K levels. “If P and K soil tests are in the high or very high category, skipping applications for a year or two should not impact yield,” suggests Angie. 

Additionally, evaluate in-season applications of N as the season progresses. It can be challenging to switch plans to use other forms based on equipment and product availability. “Consider your options and prices,” states Angie. “Also consider that we had a warm, early spring that should contribute more soil nitrogen due to mineralization and very little rain that caused nitrogen loss.” In terms of fall application, consider N application decisions for the subsequent growing season in the fall before any planned anhydrous or manure applications. “If this growing season remains dry, there is an increased likelihood of having residual N this fall that may allow for a reduction in application rates for the following growing season,” adds Angie. 

Many Midwest farmers have become accustomed to planting, spraying, and harvesting in consistently wet field conditions in recent years. However, if navigating the changing weather pattern is challenging, use these agronomic tips to make farm management decisions that will protect your seed, crop protection, and nutrient investments for a more profitable and yield productive year.  

For additional agronomic questions, contact: 

Angie Rieck-Hinz

Extension Field Agronomist

Wright County Extension Office

2302 Madison Ave

Clarion, IA 50525

Cell: 515-231-2830

Email: amrieck@iastate.edu

Twitter: @nciacrops