Precision Forage Management

Significant reductions in nutrient imports can only be realized by more precise management at every step along the farm system. Opportunities to reduce nutrient imports exist within the soil/crop subcomponent of the farm system. It involves managing the nutrients that remain on the farm to the greatest degree possible for the sustained production of high yielding, high quality crops while minimizing nutrient losses to the environment and degradation of land. It requires a shift from the use of insurance nutrient applications and book values in crop plans and herd diets to practices grounded in precision management and optimizing nutrient use efficiency.

With a focus on the crop and soil management side of the dairy farm, what can we do to minimize nutrient imports and losses to the environment? Below are some considerations for evaluating how well nutrients in soil, organic matter, and from applications are used by field crops and delivered to the next enterprise on a dairy farm (e.g. feed storage or the herd).

1. Keep good records of crop yields, rotations and manure applications.

• Efficient use of future nutrient applications relies on a good history of crop production in order to factor in N credits from sods and manure applications to meet the yield potential for the field.

2. Select the crop to meet the soil and environmental conditions.

• Base crop and rotation selection on soil types and yield potentials.
• Select species and varieties for optimum quality as well as yield.
• Selection in favor of non-fixing crops where manure N is abundant.
• Explore opportunity crops (e.g. brown mid rib sorghum sudangrass) and test their performance on the farm.

3. Know your crop requirements and apply nutrients only when they are needed.

• Manure and fertilizer applications should be adjusted based on information provided in “Nitrogen Guidelines for Field Crops in New York”, Cornell University Department of Crop and Soil Sciences Extension Series E03-16 (Ketterings et al., 2003b).
• For corn, pre-plant (other than starter fertilizer) and early post plant broadcast applications of commercial nitrogen without the use of nitrification inhibitors are not recommended.
• If starter nitrogen must be broadcast (e.g., for small grains or new seedings of grass), apply fertilizer as close to expected planting date as possible (ideally within 3 days or less).
• For row and cereal crops, including corn, maintain starter fertilizer nitrogen rates below 50 lbs/acre actual nitrogen and apply any additional nitrogen if required at the time of greatest nitrogen demand (side-dress application).
• Evaluate the need for side-dress nitrogen applications based on the pre side-dress nitrogen test (PSNT) or other soil nitrate-nitrogen tests.
• Side-dress applications should be made after the corn has at least four true leaves.
• Base phosphorus and potassium applications on regular soil testing and information provided in “Potassium Guidelines for Field Crops in New York”, Cornell University Department of Crop and Soil Sciences Extension Series E03-14 (Ketterings et al., 2003c) and “Phosphorus Guidelines for Field Crops in New York”, Cornell University Department of Crop and Soil Sciences Extension Series E03-15 (Ketterings et al., 2003a).

4. Manage the crop for optimum yield and quality.

• Use Integrated Pest Management (IPM) to minimize pest and disease pressure.
• Choose tillage and other field equipment options and timings to minimize soil compaction.
• Is adequate equipment and/or labor in place to manage crops for optimum yield and quality (e.g. timely nutrient applications, tillage, planting, pest control, harvesting, etc.)? Is there a place for a custom operator?
• Harvest at the right stage of crop maturity and moisture content.
• Harvest quickly to minimize losses in the field.

5. Keep the ground covered.

• Sod crops should not be incorporated in the fall. Chemical sod killing may be carried out when the soil temperature at four-inch depth is approaching 45^oF. Depending on location, this will not likely take place until early October.
• Plant winter hardy cover crops whenever possible, regardless of, but especially when fall manure is applied (e.g., rye, winter wheat, or inter-seed ryegrass in summer).

6. Manage manure wisely.

• Unless the New York Phosphorus Index identifies the need for phosphorus based fertility management, manure application rates should be based on Cornell guidelines for meeting crop nitrogen needs.
• Minimize fall and/or winter manure application on good grass and/or legume sod fields that are to be rotated the following spring.
• Appropriate ammonia conservation is encouraged. Losses can either be reduced by immediately incorporating manure or eliminated by directly injecting manure as a side-dress application to growing crops.
• Manure may be applied in the fall where there is a growing crop. Judicious amounts of manure can be applied to or in conjunction with perennial crops or winter hardy cover crops. Applications should generally not exceed the greater of 50 lbs/ace of first year available nitrogen or 50% of the expected nitrogen requirement of next year’s crop.
• Frost incorporation/injection is acceptable when soil conditions are suitable but winter applications should be made in accordance with the New York Phosphorus Index.
• Manure nitrogen application on legumes is acceptable to satisfy agronomic requirements when legumes represent less than 50% of the stand. When legumes represent more than 50% of the stand, manure may be applied at a rate not exceeding 150 lbs of available N/acre.