Soil health practices often require an investment of time and money. However, when properly implemented, they can yield good results.
Whether you are looking for ways to raise crop yields, reduce fertilizer use or improve your soil’s condition, this article will help you learn what is happening in your soil environment.
Soil health testing is a great way to understand the soil’s texture, type and structure. It can help farmers decide what crops will grow best on the land and inform their land-use decisions.
For example, a physical test can determine the amount of sand, silt and clay in the soil and how well it drains or holds water. This information is important when deciding whether to use the land for farming, wildlife habitat or infrastructure building.
The best way to perform a physical test is to take samples throughout the field to get a representative picture. Choose a location that is as uniform as possible regarding soil type, slope and tillage management history. Then, sample as deep as you can and follow the sampling instructions for the test you’re doing.
Soil testing can identify nutrient deficiencies and help maximize the effectiveness of chemical fertilizers. It can also help farmers make more informed decisions about soil management practices, promoting sustainability and reducing the need for synthetic fertilizers and other inputs.
During the testing process, soil samples are taken and sent to a lab that dries them and analyzes their chemistry. The results indicate how much nitrogen (N), phosphorus (P) and potassium (K) are available in the soil and what the pH is.
Soil pH determines how acidic or alkaline the soil is, which can impact nutrient availability. A proper pH level can also help prevent the damaging effects of heavy metals in the ground and enable better weed control. A laboratory test can identify which nutrients are deficient in the soil and recommend appropriate amendments, such as adding lime or fertilizer. These tests can also help farmers make the most of crop rotation and avoid nutrient runoff.
Healthy soils can carry out various functions, such as promoting crop growth through organic-matter decomposition, reducing soil loss or contamination through enhanced aggregation, and mitigating climate change through carbon sequestration. Unfortunately, no single test can measure these complex biological soil properties.
Biological soil tests measure the metabolic activity of soil microorganisms to assess their capacity to carry out critical functions. Historically, total soil organic matter and its chemical components have been used as an indicator of the biological ability of soil to cycle nutrients, decompose organic amendments, and catalyze and stabilize ecosystem processes.
Newer tests focus on the metabolic activity of specific groups of soil organisms and provide more useful information for farmers. For example, measuring the population size of key soil fungi (e.g., Rhizoctonia) using molecular techniques provides a more precise indication of how these organisms might function in the field. This information can then be interpreted using a compiled database of microbial functions to generate a soil microbe functional profile that guides management decisions.
Many laboratories offer basic soil testing that includes pH, phosphorus (P), potassium (K), and calcium (Ca). Other tests may consist of sulfur (S), manganese (Mn), iron (Fe), magnesium (Mg), boron (B), copper (Cu), zinc (Zn), chromium (Cr), molybdenum (Mo), lead (Pb) and organic matter.
These test results are a guide to help you assess the state of your soils and make decisions to improve them, whether through reduced tillage or crop rotations or by importing organic matter or nutrients. These tests also provide valuable information to determine environmentally sound limitations on nitrogen, phosphorus, and other nutrient application rates.
However, it is challenging to correlate soil test values with water quality. Several studies have found that soil test values are related to various factors, including soil properties, management practices, weather conditions, and crop species. As a result, these relationships have been challenging to establish. These problems have led some researchers to question using soil-test data to predict environmentally unacceptable nutrient loads in watersheds.