Impact of soil conditions

[brother steve]

Thought this was interesting. Its a Pdf from a plasma cutter grounding plan I'm working on. But I am always thinking of metal detecting.


Impact of soil conditions on grounding. Though the overall effectiveness of a buried grounding system depends on many factors, the resistance of the earth (or earth resistivity) significantly impacts overall impedance of the buried conductor. Soil characteristics, such as moisture content, soil temperature and type, determine the overall resistivity of the earth. When grounding your system, always keep the following in mind:
 Moisture content.

The soil's moisture content is important because it helps chemicals in the soil that surround ground conductors carry the electrical current. In general, the higher the moisture content, the lower the soil's resistivity. When moisture content falls below 10%, resistivity increases significantly.
 Soil temperature.
 Soil type.
Temperatures below freezing also increase soil resistivity. As soon as moisture turns to ice, resistivity
increases sharply. In areas subject to freezing, driving a ground rod below the frost line is required to maintain a low-resistance ground.
Black dirt, or soils with high organic content, are usually good conductors because they retain higher moisture levels and have a higher electrolyte level: leading to low soil resistivity. Sandy soils, which drain
faster, have a much lower moisture content and electrolyte level. Therefore, they have a higher impedance. Solid rock and volcanic ash, such as that found in Hawaii, contain virtually no moisture or electrolytes. These
soils have high levels of resistivity, and effective grounding is difficult to achieve. See Table 1 (in original article) for resistivities of different soils.

 

[IDXMonster]

Very interesting read Steve,I enjoy someone else's curiosity in every aspect of the hobby and how the environment itself in particular affects our outcome on a given hunt. We can do all the situational testing we want with test boxes and gardens and air testing,but....EVERY target is its own animal,regardless if the makeup of it is exactly the same as the next. Thats where it really counts to have a machine that performs well in a wide variety of environments,and to know it well. I've had ASTOUNDING success with the CTX,for example,because it's just very capable in the first place. It WILL find stuff. Some "lesser" machines CAN find that stuff. There's a long leap between "WILL" and "CAN". And somewhere in that long leap are all of the factors that your article mentions. Very very interesting stuff. Minelab has the EMI,ground mineralization and ability to see multiple targets on screen covered. But there are always at least a few other variables...

 

[Architex]

The ability to see more than one target is my favorite thing about my CTX.

 

[glenn3-88]

Never really put much thought to it but just as in deer hunting there are more productive times to go hunting, so is there more productive times
to metal detect. I have always had best luck after a rain whether heavy or light (1/2") has had time to soak in. Always seems that
the detector responds faster, louder, and with more depth. Another thing, where I live is very loamy thick soil and clay after you get down
past 6 to 8 inches. However, I own another farm about 9 miles north of where I am that is black sand. Normal dry conditions there you
can get a lot of depth but after it rains, the depth and accuracy increases dramatically because of the looseness of the sand.

Makes sense that if there is an old homestead in loamy clay conditions to hunt there soon after a rain and spend your dry time in sandy
soil if you have these conditions as I do here.

All that being said, there is one last soil condition you really would want to avoid UNLESS you have had a recent rain. Here in S. C. we
do have areas of Sandy Clay. It is hard as a brick when hot and dry. The only time I hunt it is the day after a good rain regardless of
how much rain due to it being on a hill. It's so hard that it takes a long soaking rain to penetrate the hard surface. In 3 more days, you're
out of luck.

Brother Steve, you are dead on, on this soil condition. I compare it to grabbing a 110 volt raw wire standing on concrete with rubber boots
as opposed to standing in a foot of water barefoot. Moisture produces better, more dependable return.

Great advise.

 

[IDXMonster]

Well stated Glenn. Us working stiffs have to hunt when we can but if you can pick and choose,it makes ALOT of sense to pay attention to these things!