Agricultural productivity depends on the farmland quality, and a soil test can timely report a problem in crop growth conditions. Field suitability analysis helps choose the appropriate crops or decide on land use for farming.
Regular soil testing is ultimately important not only for growers but can provide valuable field insights to all agribusiness players, including agri-coops, crop insurers, banks, input suppliers, or commodity traders. Nonetheless, designated laboratories describe only the current field properties. So, while analyzing soil test results for decisions on field amelioration, it’s better to combine lab reports with historical data from satellite imagery analytics.
What Is Soil Testing?
It is the farmland analysis for multiple parameters like chemical content, toxicity, pH level, salinity, earth-dwelling biota, etc. Such tests also provide information on chemical contamination, humic or organic content, electric conductivity, cation exchange capacity, and other physical and chemical properties.
Types Of Soil Tests
The analysis type depends on the explored components or properties of the field ground that may beneficially or adversely impact crop development. The most frequently-used types analyze and measure:
• mineral content,
• pH level,
• soil moisture,
• salinity,
• pesticides and chemical contamination,
• structure and texture, etc.
Soil Nutrient Testing
Valuable information on nutrients content allows accurate fertilization to support plant needs within precision agriculture implementations. This is why the chemical test for soil nutrients is the most common.
Primarily, soil tests report on the content of nitrogen (N), phosphorus (P), and potassium (K), which are the most important nutrients for crops. Secondary nutrients to examine are calcium (Ca), sulfur (S), and magnesium (Mg). An extended test also includes minor elements like iron (Fe), manganese (Mg), boron (B), molybdenum (Mo), and others.
To test soil nutrient content, a sample is added to an extractant solution and mixed (typically by shaking). Then, the liquid content is filtered and analyzed for chemical elements’ presence and concentrations (converted to dry matter). The obtained number is the soil-test index
Soil Acidity Test (pH)
Proper pH in the field is essential for plant productivity, and either too high or too low pH will adversely affect crop growth. Testing pH of soil, one calculates its hydrogen ions. pH values may range from 0 to 14. The neutral value is 7, lower levels are for acidity, and higher than 7 mean alkalinities. Acidic or alkaline fields are treated correspondingly. For example, pH can be raised with lime, and an accurate pH test helps determine its required quantity.
Soil Salinity Test
In saline fields, plants suffer from osmotic stresses due to poor water absorption. Soil salinity testing helps understand the suitability of lands for agricultural activities. Field salinity can be analyzed through:
• evaporation of total soluble salts (TSS) from the ground-water extract;
• measuring the electric conductivity (EC) of a saturated paste extract or a distilled water-earth dilution
Testing Soil For Pesticides and Contaminations
Pesticides help control any non-beneficial organisms that destroy crops. Chemicals effectively suppress weeds, manage crop diseases, or combat pests. At the same time, such substances poison non-target organisms and pollute nature. Highly aggressive substances leach into groundwater, remain in the land for many years, and harm humans and animals, accumulating in food. Chemical contaminants reduce the yield quality, so it is important to conduct testing soil for pesticides before seeding and plan subsequent crop treatment based on past field activities and productivity.
It is also recommended to check the presence of heavy metals during soil testing because some of them are very toxic.
Soil Moisture Testing
Water is essential for plant growth, and vegetation cannot develop properly under a lack of ground moisture. When the field’s surface is dry, it can be noticed visually; yet accurate water rates are measured with soil moisture sensors or in the laboratory. A soil moisture content test reports water availability for plants or their dehydration. High-temperature moisture evaporation from samples is the typical soil moisture test. The calculation of moisture rates in the samples is based on measuring their masses before and after evaporation.
Physical Soil Testing For Texture And Structure
Apart from the chemical content, agricultural soil testing also analyzes the soil type and its physical properties like texture, structure, and moisture.
The main components are clay, sand, and silt, and their proportions define the ground texture and its ability to retain nutrients with moisture. For example, sandy fields dry faster than clay ones, so a soil texture test helps in precision irrigation and fertigation planning.
Soil structure describes the size of its parts and pore spaces, which affect the flow of water and air in the earth. Clay fields are finer, and their pore spaces are small. Therefore, they are prone to compaction and require regular aeration.
It is important to monitor the moisture in the field before seeding and throughout the whole season to get high yields. EOSDA Crop Monitoring allows checking the surface and root-zone moisture levels remotely. Besides, historical data shows the moisture level at each plant growth stage. Based on this data, farmers can predict the moisture deficit and make proper decisions. Additionally, the NDMI index on EOSDA Crop Monitoring helps find critical zones, and further soil moisture sampling of these areas will show if they are indeed dehydrated.
How To Get The Soil Tested?
Deciding on how to conduct a soil test, you can choose any options:
1. Do it yourself with special kits.
2. Send samples for a professional analysis to a state or private laboratory. Soil test procedures in some local labs are free.
3. Hire a company that will cover the whole process from sampling to field amelioration recommendations.
Soil Testing For Agriculture
Timely field health analysis helps mitigate economic and ecological risks not only in farming but the whole agricultural sector:
• agriculturalists can avoid crop diseases and improve farm performance;
• agri-coops can monitor their members’ productivity;
• input suppliers can understand the demand in their products;
• crop insurance companies can track proper field maintenance when validating claims;
• bank institutions can decide on the expediency of granting agricultural loans.
Soil sampling and testing are also necessary when buying a new field or deciding on land use. The analysis of field nutrients helps maintain long-term field fertility, contributing to sustainable agriculture.