An Introduction to Ground Mineralization

by Daniel Bernzweig

Ground mineralization is a term used for how magnetic the ground is around us. While it refers to the ground being magnetic, it doesn't mean that the ground possesses its own magnetic field. However, it does mean that grains or particles in the Earth's soil will produce a magnetic response.

Unfortunately, mineralized soil is an issue for detectorists. In fact, mineralization in soil occurs all around us, even though we may not realize it. It is a metal detector's worst enemy when searching for treasure or underground utilities with industrial metal detectors as the Earth's magnetic field triggers sensitive devices. You may experience frustration and confusion due to ground mineralization. Common pipe cable and cable locatorsleak detectors, and ground penetrating radar units can also be impacted by ground mineralization.

What Is Ground Mineralization?

Ground mineralization occurs due to the magnetism in the soil. There are particles in the soil that have metal characteristics. More specifically, one may wonder what mineralization is. These characteristics of metal create a magnetic response. Detectorists worldwide grow frustrated with ground mineralization as their coils and metal detectors react to the magnetism created by the ground. 

Even searching new ground and soil could result in error readings due to ground mineralization, although the new ground is typically lower in mineralization. Accurate metal detection can be difficult to obtain on the ground with heavy mineralization. False signals or an inaccurate signal response can lead you to dig where there isn't any treasure or artifacts belowground. 

Understanding Mineralization

The Earth's soil combines silica (sand), decomposed plant and animal material, and various minerals such as iron, copper, and other items. Some areas and regions have a larger percentage of minerals than others do. These areas or regions are known as being highly mineralized. 

Looking deeper into ground mineralization, old soil is exposed to various surface conditions. Exposure can take place for long periods of time. Old soil is, therefore, the most highly mineralized. Old soil's mineralization is due to rainwater pushing iron compounds to the ground's surface. 

New soil is created by erosion, glacial action, and river water movements. At the time of the last ice age, new soil began to be created by erosion, glacial action, and water movements. New soil is low in mineralization. Highly mineralized soil is typically the color red or reddish in color.

Specific minerals in the soil trigger signals from metal detectors. These minerals may trigger false signals. Mineralized soil makes it difficult to separate good search targets from false signals. 

Where Mineralization Matters

Ground mineralization matters in a variety of fields and not just metal detecting. Mineralization can affect how a person works, from farming to building houses. The nutrients and minerals in the ground can create problems. Generally, ferrous buried materials are considered trash targets in the case of ground mineralization. Metal detectors should be able to detect non-ferrous materials but not ferrous ones. For ferrous/non-ferrous discrimination, buried targets must produce a stronger signal than mineralized soils to be recognized.

As we noted in our article on operating frequency for metal detecting, "Ground mineralization affects the normal use of a metal detector. Pulse Induction metal detectors are not affected by mineralization. However, a lower frequency is most often the best choice for a highly mineralized search area. A higher frequency will more likely be affected by the ground’s mineralization. Temperature fluctuations can also impact the frequency." We also noted in the same article that "Frequency is the number of waves per unit of time measured in kilohertz or kHz. This is the number of electronic waves passed through a metal detector into the ground when you are detecting metal objects. An example of a 12 kHz frequency is when a metal detector transmits and receives 12,000 times every second. If a signal repeats itself 15 times every second, its frequency is 15 Hz." Finally, in that article, we noted that "The latest multi-frequency models are fast and provide excellent detection depth. These technologies include Fast Multi Frequency (FMF) and Simultaneous Multi Frequency (SMF). Multi Frequency detectors like The Legend from Nokta Makro and the XP DEUS 2 incorporate these newer technologies." 

Archeology

Ground mineralization can create false signals for archeologists searching for artifacts and other items. False signals created by minerals may lead an archeologist to believe a metallic target has been found when in fact, there is no artifact. 

Construction

A ground's composition may make it difficult to build a building, house, or parking lot in a mineralized area. Clay soil contains more than 38% water, making it difficult, if not impossible, to build a structure on it. Because of the structure's weight, the soil will likely move and cause damage. Specialized equipment may be required for drilling. Wet sand is also problematic for construction as it is difficult to keep it from moving. A geophysical survey or a geophysical mapping may be needed before construction begins.

Farming

Soil health is paramount to farming. If new soil is devoid of nutrients, then farmers may be unable to grow plants. Phosphorus, calcium, magnesium, and boron are the four main ingredients that soil needs to be healthy. Such soil minerals are vital to farmers, and if they are lacking, fertilizers may be used. 

Landscaping and Gardening

Much like farming, landscaping and gardening need the big four minerals to produce healthy lawns and plants. The soil surface needs to be rich in minerals and nutrients to provide a strong growth area for plants. Magnetic soil signals may be produced by the minerals in the soil that has been heavily landscaped or gardened. 

Other Types of Mineralization

Mineralization improves the bioavailability of nutrients that were in decomposing organic compounds. There are other types of mineralization other than ground mineralization. These include:

Carbon Mineralization

Carbon mineralization occurs when carbon dioxide becomes a solid mineral. When carbon dioxide becomes a carbonate, it has experienced carbon mineralization. Carbon mineralization happens when specific rocks are exposed to carbon dioxide, and a reaction occurs. Carbon is unable to escape into the atmosphere when carbon mineralization takes place.

Nitrogen Mineralization

Nitrogen mineralization is a process in which inorganic nitrogen is obtained through the decomposition of dead organisms and the degradation of organic nitrogenous compounds. During the process, there is a release of ammonium.

The Science Behind Mineralization In Soil

Mineralization is described as the process of converting biomass to gaseous, liquid, salt, and mineral forms, as well as residual biomass. Mineralization is complete when all of the solid carbon has been transformed into carbon dioxide, water, and methane through aerobic or anaerobic degradation processes. The microbial carbon and energy cycles depend entirely on substrate absorbed into biomass for growth and soil respiration, with carbon dioxide and water being discharged into the atmosphere.

What are the Fundamentals of Mineralization?

Mineralization is the primary process by which microorganisms transform soil organic materials into plant-available forms of nitrogen. A sample's N ratio determines whether it has a normal distribution. The soil n mineralization is important to follow for this reason. Among the many soil properties that can be used to describe soil is soil pH.

Soil organic matter is classified into four categories: plant residue, particle organic matter, humus organic matter, and refractory organic matter, which is composed mostly of charcoal. These many kinds of organic matter include varying amounts of critical nutrients such as carbon, nitrogen, phosphorus, and sulfur. Variations in these ratios, such as the n ratio, may affect the rate of breakdown, hence altering the availability of nutrients from mineralization.

Mineralization is a continuous process that produces plant-available nitrogen before and after sowing. Mineralization rates vary according to soil temperature, water content, and, depending on the soil type, organic matter, and residues, as well as pH - mineralization is slower in acidic soils.

The Importance of Nitrogen in the Soil

There is no doubt that soil nitrogen is one of the most important nutrients for plants in the field of soil science. It is well known that soil nitrogen can be found in several soil forms. However, it is not evenly distributed throughout the soil profile. Plants take up different amounts of nitrogen depending on their needs at any given time. Plants will grow slowly or stop growing altogether if soil nitrogen levels are low. It does not matter if it is organic or inorganic n in the soil; just the presence of nitrogen in the soil biology is the key.

In crops grown in southern Australia, peak nitrogen requirement often occurs several weeks before peak mineralization. This is partly because, early in the growing season, low temperatures inhibit mineralization. Mineralization reaches a zenith in the spring when soils begin to warm, and its pace varies across seasons.

During the peak of crop development in mid-spring, a plant's daily nitrogen needs maybe four to five times the mineralization rate. For an average loam soil containing 1% organic carbon, the maximum mineralization rate is 1kg/ha/day. Mineralization occurs more slowly in sandier soils. At this stage, a fast-growing crop will need 4-5kg/ha/day of nitrogen.

Can Farmers Enhance Mineralization?

By increasing soil organic matter with bean residues, mineralization may be accelerated. Summer and fall mineralization rates may be so high that legume residues are depleted. This suggests that the mineralization rate in the subsequent crop is the same or less than in soil devoid of legume residues. Growers should bear this in mind when planning fertilizer application rates.

Weather factors that impact mineralization may also affect nitrogen losses, such as leaching, which is most prevalent during rainy winters on sandy soils, and denitrification, which is the loss of soil nitrate as nitrogen gas, which occurs most often during the summer on saturated heavy soils. Growers would be wise to focus on boosting nitrogen usage efficiency by finding the optimal nitrogen application rates and timings rather than on individual losses. The sooner N is absorbed by the crop, the lower the risk of loss.

As a result of N mineralization, organic matter is converted into nitrogenous compounds such as ammonia or nitrate. Nitrogen fixation occurs when microbes use energy derived from light to combine atmospheric dinitrogen gas molecules into ammonia. Because no energy or nutrients are required, this process is also called biological nitrogen fixation.

Soil n combines observations of the surface and subsurface with models of the processes governing these systems to model the earth system. As a result of this approach, many advances have been made in understanding the dynamics of the land surface, including the discovery of vegetation's energizing or greening effect on the atmosphere.

Plant Growth in Agricultural Applications

Plant growth in agricultural soils and crop yield are strongly influenced by soil moisture content. Plant distribution across the landscape is affected by water availability. It is often the texture of the soil that determines how much water it can retain. Soil supports plant growth and provides nutrients for animals. Bulk density is the amount of material in a unit volume of soil. A core sample of soil is used to measure bulk density. After harvesting crops such as corn or soybeans, crop residue is left behind. These include stalks, leaves, husks, cobs, and straws. In addition to reducing soil erosion, conserving water resources, improving soil quality, and providing habitat for wildlife, residue management has become increasingly important.

Due to human activities such as farming and fertilizing, the amount of organic nitrogen or organic n in the soil has increased over time. Plant growth patterns have been affected by this increase in nitrogen content, which may be detrimental to native plants. Plants need to have nitrogen because it helps them grow, but too much nitrogen can cause algae blooms and dead zones. In terrestrial ecosystems, soil microbes play a key role in nutrient cycling and decomposition. Soil microbial communities vary widely among soils and across space and time and affect the unique soil microbial biomass of any soil sample.

Microorganisms in the Soil

There are many types of microorganisms in the soil. Many of these microorganisms vary in abundance, diversity, and activity. Organic matter decomposes into carbon dioxide and water during C mineralization. As a result of microbial activity, this process occurs naturally. The level of soil organic carbon is also important as we look at soil microorganism composition. The amount of organic material in the sample is also important. From farming soils to forest soils, the r Temperature, moisture, pH, oxygen availability, and nutrient content all affect carbon mineralization rates. The process of soil C sequestration involves organic carbon entering the soil by decomposition or plant uptake and remaining in the soil until it is oxidized to CO2. It is a fact that soil aggregates provide soil stability, allowing them to resist erosion and retain nutrients.

Microbial activity converts organic matter into humus, and mineral weathering releases carbon dioxide. Various types of soil exist, each with its own characteristics. Some soils isolate carbon better than others, but all soils contribute to global warming. Organic matter decomposition and organic carbon mineralization play a crucial role in Earth's biogeochemical cycle. As a result of this process, carbon dioxide is released into the atmosphere, which has implications for climate change. Global warming is also caused by this process, which releases methane, a greenhouse gas. Low pH values, high organic matter content, and poor drainage are typical characteristics of paddy soil. In addition, the soil property tends to be highly weathered, which reduces the availability of nutrients.

Ground Mineralization’s Implications for Metal Detecting

The surface of the world varies greatly from region to region. New ground created thanks to glacial scraping or erosion of mountains is typically low in mineralization. Old grounds that are at the surface and have been at the surface for long periods of time usually have high levels of mineralization. High mineralization levels are due to the action of water which causes iron compounds to push to the surface. Once again, red-colored soil is an indication of highly mineralized areas. 

The mineralized ground has its own electromagnetic field, just like metal detector targets. The electromagnetic field possesses two components, an X signal and an R signal (this can be seen in KBA 01 Basic Metal Detector Operation). Due to the mineralized ground's large volume, it produces a strong X signal, which is stronger than an X or R signal from a buried target. Even with a device with greater detection depth, you may still have a strong X signal. The X and R signals created by mineralized ground differ randomly from one area to another. However, over short distances, the signals remain reasonably similar.

Ground Balance

Many metal detectors come standard with manual or automatic ground balance, sometimes called the ground phase. Metal detectors with a coil placed on the ground or moved up and down when pressing a specific button enable the device to detect the ground mineralization. This allows the detector to calibrate itself to the mineralization and ignore it. Ground tracking has been made possible by advancements in technology. Ground tracking is the ability of a detector to adjust the ground balance automatically as conditions change from the original manual setting. Ground tracking was introduced by Jack Gifford of Tesoro Electronics in the Lobo model. By balancing the effects of highly mineralized and variable ground, ground tracking technology can achieve greater detection depth and sensitivity. Newer models like the Garrett Ace Apex and Garrett AT Max produced by Garrett metal detectors and the XP DEUS produced by XP metal detectors, and the Fisher F75 produced by Fisher metal detectors all include ground balance and or ground tracking. It is interesting to note that in many parts of the world other than the USA, it is referred to as ground mineralization. 

Pulse Induction

Certain types and models of metal detectors offer you pulse induction (PI) technology. Pulse induction metal detector technology can cope with mineralization. When using pulse induction technology, a relatively powerful momentary current is used to magnetize the ground. The time to zero volts can be measured precisely without any type of metal. With this type of technology, soil mineralization is reduced or completely eliminated.

© 2021 Detector Electronics Corp. - Revised September 2022