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

Eighty Percent of the Cost of a Livestock Operation is FEED

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

Is a Key Nutrient for Pasture Production

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, Lbs N/A in Late Winter and 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 contains 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

T-Sum Example Jan Jan Jan Jan 1 TOTAL HEAT UNITS MIN CMAX CDATE

This Information was Brought to you by….. Oregon State University Extension