As the calendar rolls into May, thoughts are definitely turning to field work. So now would be the time to think fertilizer.  Jeff Miller with Cornell Cooperative Extension has some tips on how much and when to apply.

"Patience, young Grasshopper."  Quoting a 70's TV series probably shows my age, (not Jeff's), but he says while you may be anxious to get in the field, most CNY fields are still to wet. But when the time is right, here's some tips on fertilizer.

Corn Fields:

You will always get a bump in production from putting a small amount (10-30lbs) of nitrogen in the band at planting. Phosphorus doesn’t move in the soil, and can be tied up readily by other soil nutrients like calcium, magnesium aluminum and iron so it is best applied in the band at planting. The need for potassium like nitrogen increases as the plant grows but unlike nitrogen potassium isn’t lost to leaching or volatilization so can be broadcast applied prior to planting. The sources of nitrogen and potassium are salts which can damage the seed if applied at a combined rate of 100 lbs/acre through the planter. Nitrogen applied at high rates, 80lbs or more, through the planter can cause ammonia toxicity and kill the seed. The optimal pH for grasses is between 5.8 and 6.2. If you plan to use a triazine like atrazine or prince for weed control raise the pH to 6.5.

Winter Wheat Fields:

Any phosphorus or potassium should have been applied at planting last fall. Grain and straw yields really respond to nitrogen fertilizer. The time of application is “green up” so right now. Only we all have to be patient or we will rut up fields in the process. Many fields are still too wet to traverse. Most wheat growers broadcast apply between 60 and 100 lbs of N /acre. You should consider treating the nitrogen with a urease inhibitor unless you can time the application just before a rain storm.

Grass Hay Fields:

Phosphorus and potassium should be applied according to soil test recommendations. Nitrogen applications not only boost yields but also increase protein content in the hay. Rates of nitrogen application recommended for grass hay is determined by the intensity of production and desired protein content. Grass hay fields that are to be harvested once or twice for horse hay should receive 50-75lbs/yr of nitrogen in two applications: at green up and after the first harvest. Dairy producers who harvest 3-4 times each year should apply 100lbs of nitrogen at green up and up to75lbs of N after each harvest. Growers looking to maximize the protein utilization by livestock should use 2 sources of nitrogen ammonium sulfate and urea. They should be combined in a 1: 5 ratio of ammonium sulfate to urea.

You can get more details on fertilizer and nutrient programs for crops at CCE's website. Or call CCE’s Ag Team at (315) 736-3394. Office hours are 8:30 to 4:40 Mon-Fri.

SOURCE:  Cornell Cooperative Extension - Jeff Miller

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