Soil Testing - Now's the time!
Organic and conventional farmers alike see the value and importance of building soil and maintaining adequate nutrients in said soil to ensure that plants are able to grow well and produce each year. As you grow different crops each year, rotate them, change drainages, adjust for pests and diseases; your fields change and that change will be reflected in the soil. At times it’s hard to tell just what is going on in the ground and your plants can only tell you so much. That’s where regular soil testing can help you gain a much better understanding and produce a clearer picture of what your fields look like and what is brewing in that soil!
What will a soil test tell you?
Completing a soil test will give you an overall analysis of what the soil composition of your field/plot is as well as the nutrient availability in your soil which is essential for crop production. Soil tests focus on key areas such as soil pH levels, organic matter %, and levels of P, K, Ca, Mg, and other nutrients. One helpful part of getting your soil tested is that you can request that the lab provide recommendations according to what you will be growing in the area. This can help in accommodating heavy feeders or other crop specific preferences.
How to take one?
As you gather a sample for a soil test your objective is to get the most representative sample of your field. As any farmer knows, your soil can change drastically within a matter of feet. The sample that the lab will use is pretty small so it's best to get many sub-samples in order to create a good blend. You want to use tools that are clean to gather the samples so as to not influence the results in any way. The more spots within your field or sample area you gather from the better. Getting as many as 10 or more sub-samples to mix will give you a more accurate result. Be sure to take about the top 6-8” of soil in a slice. Your sample should be clean of sticks and large debris. You then combine and mix the sub-samples well and from that mix you scoop out the volume needed according to your soil testing lab. Make sure to label your samples and fields/plots properly so if you are having multiple locations tested you will be sure which result corresponds with which field.
What to look at on a soil test:
pH - your pH levels tell you the acidity or alkalinity of your soils. This is measured on a scale of 0 (acidic) to 14 (alkaline), 7 being neutral. The ideal pH for most crops is between 6.0 and 6.5. Some crops, like blueberries, love a more acidic soil. Soil pH directly effects the availability of nutrients, so it's important to ensure that your pH is in the appropriate range. To raise soil pH, liming agents are applied according to the soil report. If you need to lower the soil pH the standard amendment for organic growers is elemental sulfur.
Organic Matter % - this is one of the most important parts of your soil composition, crops are made from organic matter! A good target level is 5%. Organic matter is added to the soil through cover crops, crop debris, compost, manure and mulches. It is essential in creating better soil structure, helps with water management, holds on to nutrients better, and provides ample space for beneficial microbe activity and digestion. If a soil's OM% is low, we recommend including Humic acid with your pre-plant soil amendments.
N-P-K (Nitrogen-Phosphorus-Potassium) - These are the 3 most important nutrients needed for proper crop health and performance. Phosphorus and Potassium typically have their levels recorded on the soil test analysis while Nitrogen, known for its constant variability, is usually included in a general recommendation for amending according to your crop.
Micronutrients - Micronutrients play a vital role in keeping your soil and plants healthy and productive, even though they are present in much smaller quantities than some of the other nutrients on the test. Micronutrient deficiencies can limit a plant's productivity or growth, but be careful when amending with them because too much of a given micro can harm your plants.
Places to get your soil tested:
Here is a link from The Old Farmer’s Almanac listing all of the cooperative extension agencies across the country, and links to a couple of commercial soil testing labs. Your local extension office or a Master Gardener can also help you get a soil test.
Most labs will give recommendations in conventional fertilizers or specific nutrients. If you'd like help translating a lab's recommendations into the fertilizers we offer we would be happy to review your test results and make some recommendations suited to your farm and goals.