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Fertilizing Pastures. Gene Pirelli Oregon State University. Mixed Species grazing in New Zealand Disadvantages: (1) Increased facility costs (2) Size of scale (3) Potential labor conflicts (4) Management/skill requirements. Pasture is the Most Economical Feed Source.
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Fertilizing Pastures Gene Pirelli Oregon State University
Mixed Species grazing in New Zealand Disadvantages: (1) Increased facility costs (2) Size of scale (3) Potential labor conflicts (4) Management/skill requirements Pasture is the Most Economical Feed Source
Management and Fertility • The two “Keys” to increasing the available feed from a pasture • Pasture forage is significantly cheaper than purchased feed
Important Nutrients in Soil Fertility • Nitrogen, Phosphorus, Potassium • Sulfur, Boron, Molybdenum • Calcium, Magnesium
Major Soil Nutrients • Nitrogen • Phosphorus • Potassium • Sulfur
Nitrogen Is a Key Nutrient for Pasture Production
Nitrogen Apply to Match Feed Needs and to Supplement the System
Grazing Animals Can Remove a Significant Amount of Nitrogen Fertilizer, in many cases, supplies only part of the total N consumed as plant protein
Nitrogen is a Component of Protein • Crude protein of forages are measured by Nitrogen x 6.25 • Vegetative grasses and legumes contain high amounts of crude protein • The nitrogen that is removed from the soil as plant protein must be replaced
Nitrogen • Application Rate Depends on Use • For Grazing, Apply Fall, Late Winter and Spring • Base Late Winter Application on T-Sum 200 dates • Example: 40 lbs N/A Fall, 40-60 Lbs N/A in Late Winter and 40-60 Lbs N/A in Early April
Phosphorus • Apply in Fall • Stable, Does Not Move • Soil Test to Determine if Soil Levels are Rising
Potassium • Depletes Rapidly with Haying and/or Intensive Grazing • Apply in Fall • Low Levels Reduce Grass and Clover Vigor
Other Nutrients to Consider • Lime • Boron • Molybdenum
OSU’S FG 63 • Includes recommendations for major nutrients • Helps to interpret soil test results • Provides guidelines for pounds of nutrients to apply
Fertilizer Nutrients • Are calculated as “pounds of the nutrient per acre” • For example: 60 pounds of N/Acre means 60 pounds of actual nitrogen, not 60 pounds of total fertilizer • It does not matter if we are applying commercial or organic fertilizer
Fertilizer Mixes • Listed as N - P - K • Numbers are % • Example: • Fifty pound bag of 16-16-16contains how much nitrogen, phosphorus and potassium?
Organic Material • Can be manures or natural fertilizer sources • You need to have an idea of the concentration of nutrients • Book values can be helpful • Lab Testing (if the material is consistent) is the best method
Availability • Remember that organic materials take time to break down and become available • Commercial fertilizers are rapidly available but the duration of response is less
Application Times • Manure or commercial fertilizer should not be applied when there is a risk of surface water moving the material • Manure is a greater risk since it takes time to break down
Nitrogen Fertilizer • Can be used as a tool to increase early spring forage. • Split the usual amount applied into an early and mid-season application. • Nitrogen is available when plant growth initiates.
T-Sum 200 A method of calculating the appropriate time for the first N application
T-Sum 200 A method of calculating the appropriate time for the first N application
T-Sum 200 • A method of tracking heat units starting on January 1 • Apply N when heat units reach 200 • System was developed in Scotland, used in the United Kingdom and Western Canada
Heat Units Average of the maximum and minimum temperature of the day in degrees centigrade
DATE MAX C MIN C HEAT UNITS TOTAL Jan 1 8.3 2.8 5.6 5.6 Jan 2 7.8 0 3.9 9.5 Jan 3 7.2 2.2 4.7 14.2 Jan 4 5.2 1.0 3.1 17.3 T-Sum Example
This Information was Brought to you by….. Oregon State University Extension gene.pirelli@orst.edu