By Brian Essinger, DeKalb/Asgrow Territory Manager
I know we are in the middle of harvest, but with soybeans coming off you are beginning to make fertility decisions right now.
Here are a few tips and guidelines to make sure you are not shorting yourselves and put enough fertilizer on for maximum yields in 2012. Yields are better than expected in many places throughout Ohio and that means more nutrients were removed from the soil. Your fertility decisions this fall will impact your yield in 2012. Do not short yourself.
1. Fertilize every field every year no matter which crop you are rotating to or which crop you just harvested. I am going to give you information on the big three macro nutrients, but we are seeing more micronutrient deficiencies each year. Check with your retailer on how to cover your Macro and Micro needs.
2. Variable rate is the most profitable, efficient, and economical method because it gets what you need where you want it. Do it whenever and where ever you can.
3. Base you fertilization off three things:
1) What your particular soils tests say you need
2) What your yield monitor says you removed with yield (crop removal)
3) The type of fertilizer you are applying
According to Purdue’s Corn and Soybean 2011 Guide this is what you will remove and the needs of that crop to produce maximum yields (remember what you need for specific yields is based on your CEC, Drainage, and pH so get your pH right first with 6.5 – 6.8 being ideal for most nutrients):
Nitrogen (N) Phosphorous (P) Potassium (K)
Corn .75 lbs per bu .37 lbs per bu .27 lbs per bu
Soybeans 4.0 lbs per bu .80 lbs per bu 1.4 lbs per bu
Crop nutrient needs (generally speaking, this is not a guarantee or exact for each field simply use this as a guide or baseline.)
Corn: Nitrogen (N) — .85 to 1# of N per bushel target. The amount of N needed will also depend on timing, water holding capacity, and application.
Phosphorous (P) — 15-30 ppm or 30-60 pounds is the minimum available P needed for optimal corn production. This requires regular fertilization.
Potassium (K): K levels depend on CEC of your soil. If the CEC is 5.0 then you need 90 -125 ppm or 180 – 250 lbs of K for 180-200 bushel per acre corn. If the CEC is 10.0, than you need 110 -140 ppm or 220 – 240 lbs of K for 180-200 bushel per acre corn. If your CEC is 20.0 than you need 130 – 160 ppm or 260 – 320 lbs of K for 180-200 bushl per acre corn.
Soybeans: Phosphorous (P) 15-30 or 30-60 pounds. This is the minimum available P needed for optimal soybean production. This requires regular fertilization.
Potassium (K): If the CEC is 5.0 than you need 88 – 118 ppm or 176 – 235 lbs of K for 60-70 bpa soybeans. If the CEC is 10.0 you need 100 – 130 ppm or 200 — 260 lbs of K for 60-70 bushel per acre soybeans. If the CEC is 20.0 than you need 125 – 155 ppm or 250 – 310 lbs of K for 60-70 bushel per acre soybeans.
Contact your local retailer and work with them to put together you optimal fertilization plan.