LHaag - 3/12/2010 11:05 "I did not take a profile N soil test on this field, and I have not ever seen one that told me I had enough N in my soil profile for 200+ bushels without any additional N although there is." This is still a true statement
The soil test results you posted on NTOP show sampling depths of 0-8" or at most 0-10". Still true, different field and discussion If that is how you have been doing N sampling
It is not how I do a PROFILE N test then I am not surprised that you have always shown a need for additional N. Maybe your sampling for N was done at depth and I'm wrong on this, but nonetheless, 0-6" or 0-10" isn't providing much of the whole picture with regard to soil nitrate, ESPECIALLY under irrigated conditions.
you are jumping to some pretty big conclusions and mixing data from two fields that are 80 miles apart with different histories. "I am curious if you have seen such from a test?" See attachment which shows various application levels of feedlot manure, swine effluent, and conventional fertilizer over a 10 year period and accompanying soil test for 0-2' 2-5' and 0-8' profile total.
thanks, Ill look it over in a minute as soon as I'm done nixing these assumptions.
More importantly, over on NTOP board you post the following two comments:
"There hasn't been a pound of fertilizer applied in these last 15 years." AND "I applied ..., 25 ton/acre feedlot manure in 1997, and 30 ton/acre feedlot manure in 2005."
Keep in mind these are two different situations. On this post I said these pictures were from Red Cloud (Edit oops: my bad I guess I didn't) and on the NTOP site I showed the Map with the legal for Buffalo County. These two statements are not compatible.
What is your definition of fertilizer, I would really like to know. Is atmospheric N? distilled water? Radiation from the sun? Carbon Dioxide? A dead beaver? What meets your criteria? When I say "no fertilizer" I am talking about any N P K S Zn Ca Mn Mo or any element marketed as fertilizer that has no carbon attached. what is your definition?
Over a 10 year average "here" the amount of feedlot manure to meet fully irrigated corn needs on a N basis has been 9 ton/acre/yr, to meet full P needs has been 6.8 ton/acre/yr.
I think you are over applying. You are tripleing my highest rates even on fields that have no alfalfa in rotation. No wonder you see N leaching deep. That 20ppm nitrate water talked about below is unsafe for drinking its so high.
If I understand the cropping history correctly:
93-97 Alfalfa
98 - Wheat
99-04 - Alfalfa
05 - Corn
06-08 Alfalfa
09 - Corn - this is wrong I did not state over on the other website that there was corn in 09, I clearly showed the last corn crop was in 2005 and it has been in alfalfa since
So 55 ton/ac of feedlot manure has been supplied to 3 crops that would have used the N (one of which at a much lower rate). you should know that alfalfa uses more N than corn. and will use the N from the manure before it has to trade energy to the N fixing bacteria Also, in that 55 ton I applied to that field, only 177.25# was volitile N, and 957# of N within organic matter was applied over the 15 years. Thats a 66# per year average and thats if you figure I burned up all the OM to release that N which is nonsense since OM doubled during that timeframe. The credit to subsequent crops from alfalfa also need to be considered (ranging from 20-60 lb/ac depending upon alfalfa stand), also is the OM credit of 20-30 lb/ac/yr). When you work the back of the envelope math with the manure and N credits (and tmgsssn also brings up a good point about irrg. water) nobody should be surprised that you were able to raise 200 bu corn on "no fertilizer", a statement which is a misrepresentation of reality.
Again, that is refering to the field on the other website. Also, the problem with calling it a "misrepresentation of reality" is that there are people who do not credit these items adequately and what you call a misrepresentation is exatly what I am trying to show and that is: The right Crop rotation, tillage practice, and Livestock can lead to NO FERTILIZER PURCHASES, better soil, and more profitablility. Is that a "misrepresentation of reality"? Tim
Edited by Hayinhere 3/12/2010 23:57
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Corn Harvest Pics this time
