Caution: Manage your negatives to get the most out of your springtime manure application positives
In order to make the most of spring manure applications make sure to manage for the challenges this season presents.
What are your first thoughts when you hear the word manure? My guess is those thoughts don’t include the words co-product, beneficial input, or nutrient rich, but they should. Manure is an excellent source of plant available nutrients and organic components which play a large role in improving your soil in both fertility and quality over the short and long term.
Many times the question is not whether to apply manure, but rather when to apply. Applying manure in the spring versus the fall has its advantages as well as disadvantages. Applying manure more closely to when crops need nutrients results in less nutrient loss and greater usage of readily plant available nitrogen and phosphorus. This results in not only higher usage efficiency of manure nutrients but also an overall positive environmental impact by reducing the loss of nitrogen and phosphorus from the field.
However, spring applications can also present challenges. Manure contains nutrients in both inorganic and organic forms. While the inorganic forms are readily available, the organic forms need to be further broken down before nutrients are accessible to plants. A cold spring could slow down this breakdown process. Additionally, wet field conditions during the springtime can present manure application delays and compaction issues. Remember to be patient and wait for wet soils to dry enough that manure applications may be made with minimal soil compaction. Dry enough means that if you try to knead a handful of soil into a ball, it will not retain the ball-like shape.
In vegetable production systems, manures, mostly uncomposted manures with straw or other solid bedding materials, have been linked with and may potentially enhance soil-borne diseases such as common scab or tuber soft rots. Other manure sources, such as slurries or composted poultry manures, have been shown to have little effect or even potentially suppress soil-borne diseases. Regardless, it is recommended to use disease-resistant varieties to prevent soil-borne diseases and/or apply manure in the fall. Make sure to be aware of your challenges and manage appropriately!
For more information on manure management and application, check out MSU Extension Bulletin E2893, Managing Manure in Potato and Vegetable Systems, or visit the Animal Ag & the Environment Team for additional manure land application information, including spreader calibration, manure value calculators, and manure testing resources.