Loss Of Depth In Fertilized Farm Fields ?

[miserman]

While hunting the farm fields in my area,it seems that many of the targets that I recover are in the 4-5 inch range. Very few "coin like" targets are recovered in the deeper 6-10 inch range. I realize that the uneven ground of the fields can come onto play and cause a loss of depth. Does anyone have opinions on the various fertilizer chemicals causing a noticeable true loss of depth ?

 

[Ronstar]

I know fertilizers can make ugly coins for sure….
But I feel if in a farm field that is disced every year that that action has a tendency to bury shallow items and bring up buried ones. Process reverses every time the field is plowed.

 

[Minelab Pirate]

Experiment with your gain (sensitivity). Too much in a fertilized field cuts your depth dramatically.

 

[Monte]

Every detector I have and use is set to turn on at 95% to 100% Sensitivity setting. I only reduce it when the EMI requires it. Over 5 1/2 decades of very avid detecting in plowed fields, well manicured yards and parks and schools that are also treated, and I can not think of a time when fertilizer could be blamed for a reduction in depth.

Monte

 

[miserman]

Experiment with your gain (sensitivity). Too much in a fertilized field cuts your depth dramatically.

Thanks for responding Minelab Pirate...Is this documented in any manuals that I could read? Has anyone else known this to be so?

 

[Coin Rescue Inc]

Found this on this subject - It appears to state that irrigating (adding water) to fertilized soil can cause a chemical reaction that could emit IONs that charge electromagnetic particles that can emit EMI.
So if the soil is wet it could have some effect. Of course though I am not an expert on this...Maybe I should stay in my own lane...

Electromagnetic induction (EMI) data are often used to investigate spatial and temporal patterns of soil texture, soil water content and soil salinity. We hypothesized that the EMI methodology might thus also offer potential to detect agricultural legacy effects originating from fertilizer application and irrigation of different fields. Therefore, we performed EMI measurements on two long-term field experiments (LTFE) at Thyrow near Berlin (Germany) that differed in agricultural management with regard to long-term irrigation in combination with mineral (NPK and lime) and organic amendments (straw and farmyard manure). Two different rigid-boom multi-coil EMI instruments were used to measure simultaneously the apparent electrical conductivity (ECa) over nine different depth ranges to study the entire soil profile from topsoil to deep subsoil. Additionally, soil samples were taken from the different treatments to ground-truth the measurements and disentangle the nutrient application or irrigation effects from natural soil heterogeneity. The soil samples indicated a rather homogenous soil and the correlation between soil parameters or states were not significant. However, the treatments showed significant differences in measured ECa values. In general, ECa values were largest on regularly irrigated as well as on mineral and organic fertilized plots, with regular irrigation exhibiting the largest impact on EMI records even though the last application was months before the EMI measurement. Overall, this study reveals that EMI data can support the classical in situ assessment of agricultural management effects within LTFE, while offering new potentials in detecting and understanding legacy effects of agricultural management on spatial soil properties at farm level.

 

[Minelab Pirate]

Thanks for responding Minelab Pirate...Is this documented in any manuals that I could read? Has anyone else known this to be so?

What I can tell you is from personal experience. Many use way too much gain, using maximum sensitivity even in highly mineralized soils. YOU need to experiment with your machine. Personally, I would try running it at at 6 (1-10), and judging for yourself.

 

[miserman]

Thanks Minelab Pirate. I use a Fisher F75 and usually run Sensitivity in the mid to high 80's. I will try running lower as you stated.

 

[Minelab Pirate]

Let us know your results. Big Silver & Gold!

 

[IDXMonster]

If this “ion thing” is correct, at some point I’d think that it would come across the machine as EMI, and present itself in the audio. Running FBS, I NEVER run an unstable machine, at any point, period. Just remember (again) that 99% of machines are already “seeing” everything. The only control we have is in the return signals, and if we want to hear them or not. Increasing or decreasing Sensitivity on an FBS machine is not ”adjusting the power”. The Sensitivity in this case is a signal gate.

 

[bootyhoundpa]

I would highly recommend staying out of any fields that have been chemically fertilized as the potential health risks far outweigh anything you could find.. I’ve also find freshly tilled soil struggles to get great depth..

 

[Daniel Tn]

Here's my thoughts on it. A lot of fields are fertilized with animal poop and pee. Which in turn, is loaded in salt. Now a little salt probably doesn't matter but if that field has been fertilized for decades, then you have a high salt content going into it. Then when it gets wet...well you've probably experienced detecting on wet salt beaches and or salt lakes. I do think it's just enough to have an effect on detection ability. I also think this is why pulse machines do so well in fields like that...same thing on wet sand.

 

[pulltabfelix]

I would highly recommend staying out of any fields that have been chemically fertilized as the potential health risks far outweigh anything you could find.. I’ve also find freshly tilled soil struggles to get great depth..

I agree. I remember visiting a farm of a friend. And walking around found a pile of herbicide bags and read the skull and cross bones warnings: pretty much sounded like agent orange. And yes they did have skull and cross bones symbols before the warning verbage. Kind of cary that we are eating food from these fields.