Historically, residue management has been seen as a task in which only growers in a corn-on-corn rotation have needed to consider. Crop residue management has typically been seen as “reducing the trash in the field”, but thought processes should be updated on residue – especially with increased crop yields, tillage reduction, better understanding of soil fertility, and precision planting in modern crop production.
Understanding Fertility Uptake
When considering management techniques, it’s important to think about the system as a whole. Timing of fertility uptake throughout the season is shown for corn in the
graphs (right). The amount of nutrient uptake (x-axis) is shown by crop growth stage (y-axis) for each major portion of the plant (colors), also represented by the total percent. Soil nutrients taken up by grain (blue) are removed from the field at harvest, whereas the rest of the nutrients taken up are eventually returned to the soil. One of the pieces of residue management is to maximize the conversion of residue back into plant available nutrients for following crops.
Nutrient Levels on Your FarmUnderstanding how many nutrients are being removed by the crop is extremely important for building an effective nutrient management plan. Based on grain yield, you can predict how many nutrients are being removed by grain and remaining in the field as stover. For example, in a 200 bu/A corn crop, there are 220 lbs Potassium and 32 lbs Phosphate in the stover which will eventually be returned to the soil. Managing crop stover will help the timing and breakdown of these nutrients to get back to the soil and become available to future crops. As crop yields increase, the amount of nutrients found in crop stover generally also increase, making it even more important to consider residue breakdown to help nutrient management in the field. A tool that can help nutrient removal rates for your farm is the
AgPhD Fertility Removal App.
Nutrient Management One goal of nutrient management is rapid breakdown of residue. Soil microbes search out carbohydrate (carbon) rich sources for energy. Since corn stalks have very high carbon levels, the issue becomes getting those microscopic organisms across a very dense rind. Sizing residue into smaller pieces creates more surface area for microbes to enable more rapid breakdown, releasing nutrients such as phosphorus and potassium back into the soil profile. Chopping heads, chopping stalk rolls, corn head crimping attachments, or tillage to size residue are all different management practices that create more residue surface area for microbes to help speed up residue breakdown. It is important to determine which practice is most economical and efficient for your operation.
Not only is residue management important for nutrient release, but it is also important to ensure a clean furrow to plant into the following year. Hair-pinning residue in the furrow leads to uneven emergence because the basics of seed germination have been compromised; you need consistent temperature and water to imbibe the seed. Additionally, breaking up the stalk in the fall helps the soil dry out and warm up faster in the spring so you can plant in a timely manner.
In summary, residue management is important for all cropping systems. Nutrient inputs from residue help ensure plant available phosphorus and potassium at critical times for soybeans and corn. Also, reducing the carbon to nitrogen ratio in the soil can help improve nitrogen availability to the crop. Overall, increasing nutrient release from crop residue can benefit your farm.
Contact your
Golden Harvest Seed Advisor with questions or for additional agronomic insights.
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