Soil is the unconsolidated upper layer of earth composed of organic matter, rock particles, minerals, clay, gasses, liquids, and organisms that together support life. The “space” or pores in unconsolidated soil allow water and air to move through the soil, thus providing space for organic materials. Soil fertility varies from one plot of land to another depending on various factors. Therefore, it is essential to determine whether your plot of land has enough potential for crops to thrive. Soil analysis in the USA can help to find the answer.
Do You Know What a Good Soil Test Is?
A good soil test should measure at minimum the 14 essential minerals and include base saturation percentages. “Base saturation” refers to the rate of the major cations in the soil (or bases) attached to your soil’s clay component. Clay is negatively charged, so it has Velcro-like sites that attract positively charged minerals to help store them in the soil. These “bases” include calcium, magnesium, potassium, sodium, non-nutrient, acid-forming minerals, and hydrogen. It has been determined that if you can achieve an ideal balance of these minerals in your specific soil type and relative to your particular crop, you can maximize production and minimize problems.
A good soil test should provide the ideal percentages of these bases attached to the clay in your soil. That “ideal” might involve 68% calcium, 12% magnesium, 3 – 5% potassium and less than 1.5% sodium in many soils. An ideal cation balance would also involve 10% hydrogen because this amount of the acidifying mineral will provide a perfect soil pH of 6.3. This is the pH at which most minerals are available, so it is worth working toward.
Source: Freepik
Soil Testing Enhances Efficiency:
Soil testing involves a very comprehensive analysis of soil samples to assess various parameters such as nutrient content, pH levels, organic matter, and texture. This information provides farmers with valuable insights into the soil’s fertility. It aids in making informed decisions about crop selection, fertilization, and overall farm management. Understanding the composition and the health of soil is fundamental to optimizing crop yield, promoting environmental sustainability, and ensuring long-term agricultural productivity.
Soil testing facilitates efficient resource use, which aligns with the principles of sustainable agriculture. This not only improves resource use efficiency but also contributes to cost savings for farmers.
Read More: Navigating How Regular Soil Testing Can Increase Fertility in Agricultural Fields
Understanding the Soil Test Results:
Chart of Nutrient Levels:
At the first glance, your soil analysis results may look like a bunch of overwhelming numbers and ratios laid on a graph, but these numbers all relate to each other and should be considered a whole when determining your soil’s needs. The first part to consider is therefore the chart of nutrient levels.
In the first part of the chart, you’ll see the following:
- Percent organic matter
- Macro-nutrients–nitrogen, phosphorus, potassium, calcium, magnesium and sulphur
- Trace minerals – zinc, manganese, iron, copper, boron, and chloride
Percent Cation Saturation and pH:
The second part is that of the percent cation saturation, which shows the percentage of positively charged nutrients called cations. There is also a bar graph of these numbers.
- The most common soil cations – sodium (Na+), potassium (K+), magnesium (Mg++), and calcium (Ca++)
- Potassium should be 4–7%
- Magnesium should be 10–20%
- Calcium should be 65–75%
- Sodium should be less than 3%
- The remaining balance will be the percentage of hydrogen, which is evaluated as pH
If your calcium is low in the first part of the nutrient chart, adding a high-calcium fertilizer will also raise its percentage of cation saturation and lower the percentages for others, including raising your soil pH.
Electrical Conductivity (EC):
The next thing to consider is the soil’s EC or electrical conductivity. This is an indicator of how much salt is present. In this data set, salts refer to more than sodium chloride, as that is just a single type of salt. Here are some of the common salts found in soil layers:
- Magnesium sulfate
- Calcium sulfate (gypsum)
- Sodium bicarbonate
- Calcium chloride
- Potassium chloride
- Sodium sulfate
EC is considered to be high when the value is above 2.0. High EC will negatively affect crop yields, restrict nutrient availability, and negatively affect soil microorganisms.
Cation Exchange Capacity (CEC):
- CEC is one of the more critical numbers on the report.
- This measures the capacity of the soil to hold onto and use nutrients present in the soil.
- Ideally, this number would be 20 or more. If it is lower, it will improve with time as you improve overall soil health and quality.
- Good CEC is found where the soil health is excellent and is related to good microbial activity and organic matter content.
Consider your CEC level when looking at the nutrient levels and deciding on how much fertilizer to add on to.
Good CEC (20 or higher):
- A good CEC holds the nutrients in the soil so that your crops can use them for a long time.
- It will also buffer your soil against nutrient changes, so you can notice a slow, delayed effect when correcting any imbalances.
- In high CEC soils, fertilizers can be added at once and fertilized less often.
Low CEC (Less than 20):
- Low CEC soil cannot hold onto the nutrients, so when you fertilize, Whatever your plants do not use quickly will be simply leached out of the soil.
- It is almost like pouring fertilizers into a leaky bucket!
- To fertilize a low CEC soil, you must add small amounts of fertilizer frequently in place of trying to fix the nutrient levels all at once.
Lime:
Excess lime is usually fine, but if you have H in this box, you have high lime, which can be disastrous for the health of your field. If that’s the case, you’ve been adding too much calcium fertilizer. If you have an L, it’s low, and no corrective action is required. Lime is usually added in the form of high-calcium fertilizers and high lime will also commonly be reflected in a high calcium nutrient level and an alkaline pH, which is a high pH (over 7.0)
pH:
The pH reading is often probably the most misunderstood. The pH indicates the level of acidity or alkalinity in the soil.
- A pH of 7 is neutral.
- Above seven, it’s alkaline soil.
- Below seven, it’s acidic soil.
- Most plants prefer a slightly acidic soil layer between 6.0 and 6.8.
- Some, like blueberries and azaleas, like it even more acidic between 4.1 to 5.0.
- Very few plants like soil over 7.0, although some will just tolerate it like goji berries.
While a slight change from an ideal 6.8 to a too-alkaline 7.1 may not sound significant, it is actually a big jump in soil pH. It is not necessary to get your pH accurate because plants do have a vast range that they can tolerate, but your soil’s pH must be within that ideal range for your plants to thrive.
If you want soil analysis services, contact our experts at SoilOptix® today!
