Spring Manure Management

Monday, March 24, 2025

Maximizing Crop Yields & Soil Health

By Mary Loggan

As the growing season approaches, farmers face a critical task: Managing manure application to maximize its benefits for both crop growth and soil health.

When done correctly, spring manure management provides valuable nutrients to crops while improving soil structure.

However, improper application can lead to environmental challenges and missed opportunities for optimizing yields.

CCA and nutrient management specialist Christine Brown offers insights on best practices, challenges, and timing considerations for spring manure application. With careful planning and strategies, you can set the stage for a productive and sustainable growing season.

Best practices

According to Brown, “The ideal situation with spring-applied manure is that most nutrients will be available to the intended crop during the growing season.”

Factors such as the type of manure, nutrient composition, timing, and intended crop influence best practices.

She says, “Liquid manure generally has more quickly available nitrogen (ammonium-N or NH4-N) that is converted rapidly to nitrate-N (or NO3-N), while solid manure has a higher organic nitrogen content (slow-release N).

“Application of solid manure in the fall will often maximize spring availability since microbial populations have more time to break down the carbon.

“Liquid manure (especially hog or digestate, which has most of N as NH4-N) applied to a growing crop gives the best results.”

Another positive effect of using liquid or solid manure is the benefits to soil health, she points out.

“Providing microbial diversity or feeding the microbial populations already present in the soil will increase crop growth and carbon returns to the soil.

“Increased organic matter and nutrient cycling from regular manure additions also provide resilience from increased soil water-holding capacity.”

Brown emphasizes that a manure analysis can help ensure efficient nutrient usage: “Having a manure analysis or taking a sample to determine best application rate and to credit available manure nutrients means reduced commercial fertilizer.”

She points out that measuring pH and C:N ratio in a manure analysis will help fine-tune nitrogen availability and commercial fertilizer adjustments. The goal is to match nutrient availability to when crop needs are highest.

This helps farmers determine the best application rate to maximize nutrient use.

She also stresses the importance of “applying manure when soil conditions are fit (i.e., to prevent soil compaction and/or soil smearing).”

Additionally, she recommends calibrating application equipment to ensure manure is applied uniformly at the intended rate.

Challenges

While manure is beneficial, improper application can lead to environmental and operational challenges.

Brown notes that applying the wrong amount can result in environmental harm: “Wrong application rate equals too much or too little nutrients.

“Too much manure results in potential adverse environmental impacts such as water contamination from spills or runoff, or increased risk of GHG emissions.”

Additionally, she says applying manure under wet conditions can damage soil. “Application when conditions are too wet results in soil compaction.”

Another challenge is applying manure too early on frozen ground.

“Spring application ahead of ‘spring’ on snow-covered or frozen soils means there will be a lack of infiltration, resulting in nutrient loss and unpredictable nutrient utilization.”

Spring can be stressful for farmers, and manure application can sometimes compete with other tasks.

She says, “Spring is a busy time of year – too many things to do in a short window. Farmers often struggle to manage manure application and planting schedules. This can lead to planting delays, which negatively impact crop yields.

“As a result, there has been increased interest in in-crop manure application. New options in application equipment (e.g., dribble bars) allow manure to be applied after planting.”

Another challenge is that the high water content of manure can make transport over long distances expensive.

However, “The availability of certified custom applicators is making it easier for livestock farms to apply manure at the right time,” she states.

Custom applicators help farms without the necessary equipment or help to apply manure, improving timing and efficiency.

For example, she says, “A dairy farm that wants timely application on just harvested forage fields but doesn’t have manpower or equipment to interrupt forage harvest, this is where custom applicators come in.”

She also notes that the availability of technology such as frack tanks and manure bridges makes more distant applications an economical option.

Timing

Brown says, “Manure application should be planned based on opportunities.”

She says that in the spring, farmers try to spread manure as soon as possible before the crops are planted. However, delays often occur due to weather and heavy workloads. When crops are planted late, this will result in reduced yields.

If the timing isn’t working out this year, and the opportunity to spread before planting isn’t an option, it is important to consider in-season applications instead.

Brown also emphasizes that manure application should not be limited to a single season.

She suggests that for many farms, applying manure after wheat harvest is also beneficial.

“Wheat (or spring cereals) in rotation is positive for providing crop rotation diversity, spreading workload, providing more weather diversity with three-crop rotation, and the opportunity to apply manure when soil conditions are more fit.

“It also aids when planting cover crops, as manure can provide synergy for biomass production,” Brown explains.

She advises that “every farm is different – with different site characteristics, land base and economic considerations, labour and equipment profiles, interests and priorities. There is no one answer, but the goal is maximizing economic nutrient utilization for higher-yielding crops.” BF