Variable rate fertilizer

[bgmb]

Just wondering if anyone has thoughts/opinions on variable rate fertilization?

How are you applying the technology?

Are you using a third party contractor to help you eg. Farmers edge, agritrend.

Have you tried a consultant? with good or bad results?

[FarmRanger]

Been doing it for most of a decade, but we just started mapping with GPS this year. Up until this year we just punched the fertilizer rate up when we passed over eroded knolls, and down through saline or areas prone to flooding.
This year I'm going to use last years yield maps, along with my own interpretation of those yield maps and soil zone nutrient sample results, to try to fine tune those applications for fertilizer prescriptions.

Knowing that I won't get it exactly right, I'm also going to run a few oddball passes through the field to see if varying up or down the fertilizer would have paid off or not in yield or savings.

If a consultant can cost effectively help you interpret yield data and soil sampling to set up fertilizer prescriptions, then hire them. Know what you're hiring them for before you sign up with them though.
My 2 cents.

[craig]

We are in the second year working with farmer's edge and a local independent crop consultant. In our area with high variability and good moisture we think variable rate will really pay. We think we are getting huge benefits in the ability to use farmer's edge's previous experience.Not much different than direct seeding. The more you learn from someone else the less mistakes you make in the field.A note on Farm Ranger's comments.While on the surface it would seem to make sense to increase fertilizer in the poor areas of the field, you need to realize that fertility may not be the limiting factor in those poor areas. One of the huge savings in variable rate is to fertilize to the potential of a zone. If you fertilize for 80 bushels and only get 50 you are basically loosing the additional fertilizer applied. The key is trying to make good yield targets for the zones. That is where yield maps can play a role.

[bgmb]

The thing I don't like about that mentality (farmers edge) is that they have no idea why a particular area of your field is "bad". It could be a severely lodged area, a hill top, a flooded out area, a saline area etc.

They will treat all those areas the same.

I have been visited numerous times by a farmers edge guy. I asked why they have no data to back up what they are selling. His response is to show me a half section split in half. But no properly conducted (replicated side by sides weighed off) trials. I'm surprised they don't have this by now the company is several years old.

[darren442]

Is anyone using the GreenSeeker? I've known about it for years but never gave it much thought. The guy from the states was on TV talking about it and what he talks about makes sense. It is a proven fact that you only use 30-50% of your applied fertilizer in the spring and the rest is wasted. I do realize you need to be using liquid fert to use the greenseeker.

I have also heard alot of good things about farmers edge. I have a precison agriculture/Gis diploma so i've studied everything they use and it is all valuable information and is a great tool. Years ago people tried to do this and they didn't have the training and it bombed but ive heard Farmers Edge are really good.

Also if you can read what a soil test is telling you it can tell you why certain spots don't produce. To much importance is put on N,P,K,S and not enough on what everything else is doing.