Maintain Optimum Nitrogen Rates Even With Higher Fertilizer Costs Mike
Rankin The high price of natural gas (and energy in general) has once again resulted in higher prices for nitrogen (N) fertilizer sources in 2004. Last year, many producers were able to pre-pay on fertilizer and avoid the over winter price increase. This year, there was no such luck as prices remained high throughout 2003 and into 2004. Table 1 shows the price ranges being currently quoted for anhydrous ammonia (NH3), urea, and urea ammonium nitrate (UAN). Total cost of applied N will depend on method of application, who makes the application, and N source.
Should I lower my normal rates given the higher prices? The first question that comes to most producers' minds is "Will it pay to cut nitrogen rates on corn?" A simple way to address this question is to consider that cutting N rates by 30 pounds per acre equates to a $7.20 per acre savings if your cost is $0.24 per pound of actual N. This dollar amount in savings translates to 3.3 bushels of $2.20 per bushel corn. Thus, if you cut the N rate by 30 pounds of N per acre and lose more than 3.3 bushels of corn per acre, a poor decision was made. The decision gets worse if you can capture a higher corn price, which certainly seems more likely this year than in 2001 when the last spike in N price occurred. Another way to analyze the impact of higher N prices is by looking at the corn price to N price ratio, with a low ratio indicating a bleaker outlook. In most years, a worst case scenario corn:N price ratio is considered to be 10.0 (for example, $2.00 corn divided by $0.20 N). In 2004, this ratio could approach 8.0 with the right circumstances ($2.00 corn and $0.25 N). However, even at this ratio, it's probably not prudent to lower rates given the volatility of grain markets and some prospect for market upside. From an agronomic standpoint….. The optimum N rate for corn is NOT determined by potential corn yield. That is, economic optimum N rate is the same for a year when corn averages 120 bushels per acre as it is for a year when corn yield averages 180 bushels per acre. This is perhaps difficult to rationalize but has been proven in countless research trials. Virtually every Midwest state makes N recommendations using factors other than corn grain yield. These factors include soil type, organic matter, previous crop, etc. Similar to grain yield, optimum N rates do not change with planting date, plant population, or hybrid maturity. Even more important - don't over apply N For most of our medium and fine textured soils, we need to insure that the corn crop has 160 lbs. N available per acre. Higher fertilizer prices will mean that not taking proper nutrient credits from manure and legume sources will be more costly. Although most producers are aware of the first-year credits following manure applications or a forage legume stand, there are also legitimate second-year credits. For example, a second year corn field in 2004 (alfalfa terminated in fall, 2002) can be credited 50 pounds of N per acre. The second-year N credit for manure is 1 pound for each ton of solid dairy manure applied per acre in the fall or winter of 2002 and 2.5 pounds of N for each 1000 gallons of liquid dairy manure applied.
|
|||||||||||||||||||||
For
more information contact 
