Nutrient Management

Farmers may apply commercial fertilizers, manure, soil amendments, or organic-by-products to provide the nutrients plants need. When determining the nutrient source that’s best for your operation, here are some things to consider:

• Best match. Choose the right nutrient sources to best match the needs of your crop and soil while minimizing the site-specific risk of nutrient loss. Needs vary depending on your local soil and climate conditions, specific crop, and conservation practices you implement such as reduced tillage, no-till, or cover crops.
• Utilization needs. Select nutrients based on your utilization needs. If you have a new planting, you may need a delayed uptake just after seed germination. Or, you may have an established crop that’s ready to take up nutrients immediately.
• Testing. Test to confirm key nutrient needs for your soil and plants. Soil tests can help you to identify the key nutrients your soil needs so you can make an informed decision on the correct fertilizer and the right quantity for your crops. Plant tissue tests can also add valuable insights. Similarly, test manure, soil amendments, or organic by-products. If you use manure or organic by-products, testing the manure for nutrient content can help meet crop nutrient needs more efficiently. This leads to increased profit and decreased risk of pollution.

SMART Tip: Testing is the most reliable way to determine what your soil and crop needs to select the best nutrient source. Testing is a key component in nutrient management planning. Contact your local extension service for more information on testing.

For effective nutrient management, method of application can make all the difference. When determining how and where you apply nutrients, here are some things to consider:

• Injection. Getting nutrients down below the surface of the soil and into the root zone of your crop increases the plant’s ability to access them. Injecting nutrients is one way to deliver them exactly where they’re needed.
• Incorporation. Specific sites may require nutrients to be incorporated into the soil, not just broadcast on the surface, for plants to adequately access them and to reduce the risk of nutrient loss in runoff events. This can be true even if you practice reduced tillage or no-till. In these systems, nutrient placement with the planter or injection via a no-till, low disturbance application tool are effective methods for nutrient incorporation. If a broadcast method is utilized, some sites may benefit from a low intensity incorporation of manure or fertilizer following the application.
• Other practices combined. If incorporation or injection are not practical, combine in-field conservation practices with edge-of-field practices to reduce nutrient losses.
• GPS and other technologies. Different parts of your land may have different nutrient requirements. Global Positioning Systems (GPS) and variable rate application are some of the technologies that can help make sure your applying nutrients in the right amounts in the right places.

Each plot of land is different. A key part of nutrient management planning is assessing the site-specific conditions of your land and operation to determine what is needed. All conditions on your farm must be considered because each affects the others. In addition, as changes are made to your operation, the on-site conditions should be re-assessed, and the plan should be adjusted accordingly.

Here are some things to consider:

• Certified nutrient management planning. A certified nutrient management planner can analyze your specific land conditions, perform a risk assessment and draft a nutrient management plan that is tailored to your land.
• Current or planned practices. Current or planned practices – such as cover crops, no-till, or conservation tillage – should be assessed to determine how they might affect nutrient requirements and reduce nutrient losses.
• Testing. Testing and analysis can tell you what nutrients are already present in the soil, soil amendment, or plant, to determine what nutrients are needed.

Many factors affect the amount of nutrients your crop needs. When determining the amount or rate for your application, here are some things to consider:

• Testing. Having your soil, plants, and – if necessary – nutrient source tested will let you know what nutrients are needed, and how much you should apply given your specific source.
• Soil health practices. These conservation practices, such as no-till or cover crops, naturally increase soil organic matter and biological processes, and thereby may reduce your fertilizer needs.
• Technology. Variable rate application technology, for example, can improve nutrient efficiency by delivering specific amounts according to historic yields and soil-test nutrient levels.

Appropriately timing the application of nutrients is critical. When determining when to apply nutrients, here are some things to consider:

• Crop demand. Nutrients should be applied when crops need them most to maximize uptake and effectiveness. You may split-apply nitrogen, for instance, to deliver nutrients at targeted times during the growing season.
• Weather and seasonal conditions. Application of fertilizer immediately before a large rainfall could contribute to nutrient runoff.
• The technology you have available. Technologies such as precision guidance systems allow producers to apply fertilizer to actively growing crops.