Corn and Bean - Fertilizing

[WTNUT]

I am looking for opinions from people who grow or have grown soybeans and corn for market sales. I know the best way to find out how much fertilizer you need is a soil test. I have done that many times. This thread is more about taking a poll from people across the country. What I want to know is how much and what type of fertilizer do you or did you generally put down per acre when growing corn and beans on year to year rotation.


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[Mortenson]

Use MAP or DAP, potash, and usually liquid UAN solution with ATS. Not getting the sulfur from the atmosphere like before, so it's important to get it from fertilizer or you'll see the deficiency. Trying different forms - ATS, AMS, and some Microessentials (MESZ) which has 50% sulfate and 50% elemental sulfur. Some guys just use elemental S while others use maybe 100# of AMS in the spring for the N and S. Might depend on what you have access to. Lots of debate on spoon feeding N vs all in one shot. Lbs needed (yield goal) and soil types will dictate that obviously. On corn/bean rotation better soils can handle a single app of 170# and "hang on" to it, around here. C/B rotation it's nice to spread for both crops every other year and save on a pass. Corn on corn rotation guys seem to fertilize every year and up the N a little. 2nd year corn may need a hair more N upped than following years of consecutive corn, the thought being the carbon cycle gets kicked in. Last year IL followed IA's lead from a few years ago and lowered the recommended rates of P and K. Here's a chart with old and new maintenance rec's, from U of IL. They're going off 200 bu corn and 60 bu beans. I think the lower rates are partially based on the old book values assuming greater nutrient removal rates from harvested grain than what has been discovered now. I think a lot of rental contracts probably assume something like 200P/200K every other year, on good IL soils anyway.

 

[WTNUT]

First, I have been on a corn after corn rotation until 2017. I am now thinking of going to C/B rotation and only want to fertilize every other year. You are spot on regarding limitations as to availability in different region. We have a lot of small farms and certainly not the same access to variety as Il and IA. Nearly everything is broadcast one shot.
I don't use 200 and 200 of P and K, little lower than that. But do more N about 185 lbs.


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[Northbound]

How many acres you talking? Easy access?
Around here if you have good access free fert is easy to come by. The big dairy farms have more liquid manure than land to dump on. We also have Johnsonville brats who will inject sludge once every 7 years. And the septic pumping company's will inject also. May be worth some phone calls

 

[WTNUT]

Well the septic goes on a couple fields owned by the system for that purpose, no brats here, and really no dairy farmers. Got to buy fertilzer.


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[FarmerDan]

Hmmm....well, its' been a long time since I grew any amount of production corn and beans. But, I still have a professional interest in watching what everyone does...and I don't see that its changed much except to get a little more sophisticated in some corners and less so in others. I guess that's a riddle. I know some of the big guys here have so many acres they don't think much about getting down to the prescription level while others do. Is there a difference in their checkbooks? Don't know.

When I did it, my fertilizer applications were based on soil and tissue test results (more soil than tissue), the price of fertilizers, the outlook for prices, and expected yields. My goal was to keep levels of P & K in the high range, but I wasn't too proud and was willing to "mine" the soil when the economics were out of wack. I'm saying nothing you don't know. The guiding principle was to fertilizer to replace the nutrients removed by the crop and the add enough, if necessary, to get the "bank" back to something approaching high to very high P, K, sulphur and boron. It works on the soils I deal with. Maybe not on other types.

In a corn bean rotation get it all down ahead of the corn crop. Around here, traditionally, DAP (18-46-0) was the cheapest way to add phosphorous with nitrogen tagging along at a minimal unit cost. The rest of the nitrogen for the corn crop gets top dressed at the appropriate time, amounts based on yield prospects. Did I mention corn is a dicy prospect in these parts. I always used elemental born and sulphur if the situation demanded it.

If I had to close my eyes and just do it, I'd blend 100 lbs of urea, 150 lbs of DAP and 300 lbs of potash to get something like 75-70-180. Then, top dress up to 100 lbs of N from UAN assuming a 150 bu corn yield. Adjust it up or down as appropriate. Some of you will be horrified at that amount of urea, but it never bothered me.

Then, the soybeans should have enough to grow a decent crop. But, remember, i'm assuming we are starting at and staying close to high levels of P & K and the economics of input costs and market prices are decent.

 

[WTNUT]

If I had to close my eyes and just do it, I'd blend 100 lbs of urea, 150 lbs of DAP and 300 lbs of potash to get something like 75-70-180. Then, top dress up to 100 lbs of N from UAN assuming a 150 bu corn yield. Adjust it up or down as appropriate. Some of you will be horrified at that amount of urea, but it never bothered me.

Then, the soybeans should have enough to grow a decent crop. But, remember, i'm assuming we are starting at and staying close to high levels of P & K and the economics of input costs and market prices are decent.[/QUOTE]

Dan your close your eyes approach is darn close to what I did for 10 years and it is jumping ahead to where I was eventually going to go with this. The only difference I made for years as compared to your closed eye recipe is I would dress 150 pounds of urea to get 144 pounds of N.

Now, did you fertilize any for beans the following year? As written it looks like you did not.

I have A LOT of friends frequently asking me how much fertilizer to use on a Corn/Bean rotation. I know they are NEVER going to do a soil test and I know they are only growing for deer. So often I hear “well it is only for deer” and the co-ops will also say that. My response is it is still your money for seed, your money for fuel, your money for herbicides and your time. There is no need for them to get too far into the weeds, but there should be a basic amount of N,P&K to keep them going. As for boron, I know several of my friends don’t have access to it as a blend additive.

I would like to hear more from others on their close their eyes approach to fertilizing a rotation. I know that isn’t the best approach, but I know there are lots of people who want to know and giving them some advise is better than them doing nothing.


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[FarmerDan]

WT, You know. It's a plan. Man plans. God laughs. Keeping P & K levels in the high range solves a lot life's little problems. All the fertilizer before the corn? It would depend on your soils' abilities to hold nutrient's. I'm assuming ours will. But, leaching is a fact of life. Let's just say I'm not afraid to not fertilizer soybeans given knowledge of what past history told me. To my friends who want a recommendation without the benefit of prior knowledge, I ask "How much money do you have?"

Let's have a little debate. What's the most limiting nutrient for corn? I'd say nitrogen. If you don't put down enough N it doesn't matter what the P & K levels are. so, spend money on N. If there's any money left, what's next? I'd say potassium. If you get corn growing with plenty of N and it won't stand up that's a bummer.

What's the most limiting nutrient for soybeans? I don't know. It's not a nutrient but maybe it's water? I guess the nutrient would be phosphorous.

 

[Mortenson]

For soybeans? Rain in August! And keep your ph up. "Here" if you close your eyes, better plan on applying 2 tons of lime every several years.

 

[WTNUT]

WT, You know. It's a plan. Man plans. God laughs. Keeping P & K levels in the high range solves a lot life's little problems. All the fertilizer before the corn? It would depend on your soils' abilities to hold nutrient's. I'm assuming ours will. But, leaching is a fact of life. Let's just say I'm not afraid to not fertilizer soybeans given knowledge of what past history told me. To my friends who want a recommendation without the benefit of prior knowledge, I ask "How much money do you have?"

Let's have a little debate. What's the most limiting nutrient for corn? I'd say nitrogen. If you don't put down enough N it doesn't matter what the P & K levels are. so, spend money on N. If there's any money left, what's next? I'd say potassium. If you get corn growing with plenty of N and it won't stand up that's a bummer.

What's the most limiting nutrient for soybeans? I don't know. It's not a nutrient but maybe it's water? I guess the nutrient would be phosphorous.

I agree that N is the most important for corn, and the “how much money do you have” is priceless. 15 years ago I had just started growing beans. All the real farmers were making fun of the new kid on the block. I was going to show them ha ha. I grew the most amazing beans anyone around had ever seen. I don’t know how much fertilizer I put down for those beans (which were following corn), but to this day I would be embarrassed to let anyone know if I did know. But, it was a lot! No way did I break even those two years.


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