The Importance of Soil Testing

Don’t guess, soil test!

Soil testing is a critical part of producing a successful crop, whether that be fruits, vegetables, forages, turf, or ornamentals. A soil test informs us of the fertility of our soil by telling us the levels of several essential nutrients present, as well as the relative acidity or pH. These results aid us in selecting plants, preparing our soil, selecting and applying the correct fertilizers, and identifying problems. Overfertilization can cause excessive plant growth, increase diseases, lead to increased pollution, as well as just being costly. Soil testing gives you precise measurements, leading to better decision making and ultimately more productive plants.

When you are considering growing a crop, the first thing you should do is conduct a soil test. This can help you make appropriate decisions and prepare your land accordingly.

Soil testing is the only reliable way to test soil pH. Soil pH affects nutrient availability to the plant. Most nutrients are at their optimal availability to plants between a soil pH of 6 and 7. However, some plants such as blueberries require more acidic soils. A soil test will tell you the pH, as well as provide you with recommendations to modify the pH for your selected crop. Substances such as sulfur can lower soil pH, while substances such as lime will raise soil pH.

Soil testing can be done at any time, however, you will want to give yourself time to allow for adjusting pH before planting if that is necessary. Depending on the substance used, It can take 6 months or more for added lime to begin providing benefits. 

So you know why to test your soil, but how do you do it? Soil testing is a service provided by Virginia Tech. You want to sample your soil when it is not too wet. Sampling in the fall is usually best for farmers to allow for adjusting pH. You want to divide the area into units if the area or field is not uniform, or if different areas are unique (garden, lawn, flower bed, crop field, etc.) You want to obtain a good, representative sample of soil. Sample in a zig-zag pattern across the area. Samples should contain at least 5 subsamples from the area mixed together, with each subsample taken at a depth of around 6 inches for plowed land, or 4 inches for pasture or lawns. You may sample with tools such as a soil probe or spade.

Soil probe with a soil core sample

The soil information sheet must accompany any sample sent to the Soil Testing Lab. This sheet can be found online or at your local VCE office. Take time to fill in the blanks to the best of your knowledge. If you need assistance your Extension agent can help you. Make sure the sample identifier on the sheet matches that of the sample box, and that you fill out the correct plant code for the sample you submit.

Soil tests at Virginia Tech are $10.00 per sample for a routine package. Routine tests make recommendations for the following: P (phosphorus); K (potassium); Ca (Calcium); Mg (Magnesium) and five micronutrients, as well as pH. Commercial farmer samples are free of charge. Results are typically received within a week, unless there is a delay due to a large number of samples being sent in.

How Does My Farm Become USDA Certified Organic?

Organic production has been growing in popularity for many years. The actual term “organic” is a labeling term used to identify agricultural products that have been grown and processed according to certain standards. These standards incorporate cultural, biological, and mechanical processes that foster cycling of resources, promoting ecological balance, and diversity (National Organic Program). While you often hear of many farmers who choose to follow the practices of organic growing, there are actually regulations which determine whether or not you are allowed to label your product as “organic.”

According to the National Organic Program, all products that are sold, labeled, or represented as organic must meet all requirements in the USDA organic regulations. This program, the USDA National Organic Program, is in place to ensure that there are consistent standards nationally. Certified organic products must become certified by a USDA-accredited certifying agent, or third-party certifier.

For small operations, there is an exemption. Operations whose gross agricultural income from organic sales is less than $5,000 do not have to be certified in order to sell, label, or represent their products as organic. They must follow organic practices, and may use the word “organic,” but are not allowed to use the USDA organic seal.

What about the rest of us?  The certification process as a whole can take on average from 3 to 6 months, and the cost can range from $1,000 to $5,000, depending on your certifier and size of farm. The first step is to find an organic certifier. There are many, and a database can be found at https://www.ams.usda.gov/. Your certifier will help you get started and will be able to answer questions. In order for your land to become certified organic, farm land must have not had any prohibited materials applied to it for three years before becoming certified. Land that has had no prohibited materials applied may become certified immediately.

You will need to develop what is known as an organic systems plan. This plan is a detailed outline that explains how you intend to operate your farm or ranch to satisfy the requirements of the regulations (ams.usda.gov). An important part of this plan is the materials list, where you list out all of the chemical and other inputs that might be used. If you needed to adjust or add to this list, you would need to contact your certifier to make sure the input is approved and not a prohibited substance.  

As far as the types of practices you will need to put into place, organic crop production puts emphasis on land having no prohibited substances added. Soil fertility and crop nutrients are managed through tillage, crop rotations, and cover crops. Supplemental nutrients may be added with animal and crop waste as well as allowed synthetic materials. Crop pests including insects, weeds, and diseases must be controlled using physical, mechanical, and biological controls. If additional tactics are needed, only those that are approved may be used. Many products approved for organic production may have an OMRI label (Organic Materials Review Institute), meaning the product has been reviewed to determine if it is allowed. Pesticides derived from natural materials or living organisms are allowed as long as they do not contain synthetic additives or are not prohibited on the National List (ams.usda.gov). You must only use organic seed or plant stock when available, and the use of any genetically engineered material is prohibited.

While the certification process may seem daunting, Virginia Cooperative Extension is available to help you and provide resources as you work toward your certification.