Crop Nutrient Management

Adapted from What’s A Crop Nutrient Management Plan (CTIC, 1999.)

Description

Nutrient runoff can degrade aquatic ecosystems and affect potable water supplies. Farmers can implement nutrient management practices to help maintain high yields and save money on fertilizers while reducing NPS pollution (USEPA, 1997). A Crop Nutrient Management Plan is a tool that farmers can use to achieve these goals.

Ten Key Components to a Crop Nutrient Management Plan

1. Field Map: The map, including general reference points (such as streams, residences, wellheads, etc.), number of acres, and soil types is the base for the rest of the plan.

2. Soil Test: How much of each nutrient (N-P-K and other critical elements such as pH and organic matter) is in the soil profile? The soil test is a key component needed for developing the nutrient rate recommendation.

3. Crop Sequence: Did the crop that grew in the field last year (and in many cases two or more years ago) fix nitrogen for use in the following years? Has long- term no-till increased organic matter? Did the end-of-season stalk test show a nutrient deficiency? These factors also need to be factored into your plan.

4. Estimated Yield: Factors that affect yield are numerous and complex. Your field’s soils, drainage, insect, weed and disease pressure, rotation and many other factors differentiate one field from another. This is why using historic yields is important in developing your yield estimates for next year. Accurate yield estimates can dramatically improve nutrient use efficiency.

5. Sources and Forms: The sources and forms of available nutrients can vary from farm-to-farm and even field-to-field. For instance, manure fertility analysis, storage practices and other factors will need to be included in your plan. Manure nutrient tests/analysis are one way to determine the fertility of it. Nitrogen fixed from a previous year’s legume crop and residual affects of manure also effects rate recommendations. Many other nutrient sources should also be factored into your plan.

6. Sensitive Areas: What’s out of the ordinary about your field plan? Is it irrigated?

Next to a stream or lake? Especially sandy in one area? Steep slope or low area? Manure applied in one area for generations due to proximity of dairy barn? Extremely productive—or unproductive—in a portion of the field? Are there buffers that protect streams, drainage ditches, wellheads, and other water collection points? How far away are the neighbors? What’s the general wind direction? This is the place to note these and other special conditions.

7. Recommended Rates: Here’s the place where science, technology, and art meet. Given everything you’ve noted, what is the optimum rate of N-P-K, lime, and any other nutrients. While science tells us your crop has changing nutrient requirements during the growing season, a combination of technology and your management skills assure optimum nutrient availability at all stages of growth. No-till corn generally requires starter fertilizer to give the seedling a healthy start.

8. Recommended Timing: When does the soil temperature drop below 50 degrees? Will a nitrogen stabilizer be used? What’s the tillage practice? Strip-till corn and no-till corn require different timing approaches than corn planted into a field that’s been tilled once with a field cultivator. Will a starter fertilizer be used to give the seedling a healthy start? How many acres can be covered with available labor (custom or hired) and equipment? Does your manure application depend on a custom applicator’s schedule? What agreements have been worked out with neighbors for manure use on their fields? Is a neighbor hosting a special event over the weekend? All these factors and more will likely figure into the recommended timing.

9. Recommended Methods: Surface or injected? While injection is clearly preferred, there may be situations where injection is not feasible (i.e. pasture, grassland). Slope, rainfall patterns, soil type, crop rotation and many other factors affect which method is best for optimizing nutrient efficiency (availability and loss) in your fields. The combination that’s right for you in one field may differ in another field...even with the same crop.

10. Annual Review and Update: Did you actually do what you planned to do? Even the best managers are forced to deviate from their plans. Did an unusually mild winter or wet spring reduce soil nitrate? Did a dry summer, disease, or some other unusual factor increase nutrient carryover? What was applied where? At what rate? Using which method? These and other factors should be noted as they occur. If you’re like most people, it’s easier to make notes as it’s being done than to remember back six to 10 months.

References

CTIC, 1999. What’s a Crop Nutrient Management Plan? Conservation Technology Information Center, 1999.