Plant Nutrition for Cool Forages

15th Apr 2014 4R Practices,Implement the 4Rs,Right Place,Right Rate,Right Source,Right Time,

By Tom Bruulsema, IPNI Northeast Director

Declining crop prices may concern forage producers as they plan fertilizer purchases for the coming year. Recent government price surveys, however, indicate price declines for fertilizers similar to those for forages. The USDA-NASS prices paid report shows fertilizer prices down by 12% for February 2014 compared to a year ago. Prices received for hay declined by a similar amount, over the same period.

Forages remove large amounts of nutrients. When hay, haylage or silage is analyzed to formulate feed rations, the analysis report also provides information relevant to managing crop nutrition. Removal equals yield times concentration. Replenishing removal to maintain soil tests in the recommended range is a sound principle of plant nutrition that doesn’t depend on prices. Applying the right nutrient source at the right time and in the right place assures optimum quantity and quality of forage, while protecting environmental quality.

Prices may have changed, but the principles of fertilizing forages have not. A new book called “Cool Forages” explains those principles well. It comprises 50 chapters of science-based information useful to forage producers in northern temperate climates. Here is a short list of important points it underscores, related to plant nutrition.

  • Many economic analyses show production of alfalfa to be at least as profitable as corn. Return on fertilizer investments that correct nutrient deficiencies can be expected to be high.
  • Perennial forages provide predictable N credits for following crops.
  • An on-line soil-crop N modeling tool at www.NLOS.ca can improve understanding of N cycling and adapt its management to local weather conditions.
  • Perennial forages lose less nutrients in drainage water than annual crops, but a greater fraction of the P loss may be in the dissolved form.
  • Understanding the methods of testing for soil P can help predict crop response to applications of P, and the potential for its loss in drainage water.
  • The mysteries of variable response to applied S are important for both the yield and quality of forages.
  • Whole-farm N budgets can help identify changes in diets, species selection and grass harvest frequencythat improve nutrient use efficiency on dairy farms.
  • Manure application timing and placement require innovative tools to optimize nutrient use.
  • Stand termination method and timing need careful management to minimize losses of nitrate and nitrous oxide.
  • Carefully managed manure applications can effectively supply nutrients for alfalfa production.
  • Mineral balances to produce a quality of timothy grass hay appropriate for the Ca nutrition of the drycow in transition can be achieved by cutting at the right growth stage, managing soil P levels, and applying Cl- fertilizers.

The book was edited by Shabtai Bittman and Derek Hunt, scientists with Agriculture and Agri-Food Canada.Published by the Pacific Field Corn Association, the book can be ordered at www.farmwest.com. Managing plant nutrition for forages is at least as technical as it is for corn. Using information sources like theseensures the highest level of precision in nutrient application for sustainably intensified forage production.

For more information, contact Dr. Tom Bruulsema, IPNI Northeast Director, Phone: (519) 835-2498. E-mail: Tom. [email protected]