Digging further into soil health

Friday, January 2, 2015

With winter months midway, farmers take steps toward preparation for the 2015 spring planting season. Soil composition is a key attribute to the success in crop farming, giving soil testing prominence in deciding where, when, and what to plant.

Soil testing is essential to farmers success as it gives insight to soil type, which is highly variant. Depending on the types of soil, there are ranges of organic matter, leaving soil heavy, light and sandy, or anywhere in between.

Routine soil testing is imperative for crucial growing areas, and allows adjustments to be made for compatibility with specific crops.

With fertilizer costs rising, using the hit and miss method is far too expensive, leaving soil testing as a more viable resource. Knowledge of soil composition is becoming more valuable as it leads to more accurate fertilizer use in a society that is highly concerned with environmental damage.

Missouri is home to three soil testing laboratories, located throughout the state. Each lab is accredited through the Missouri Soil Testing Association accreditation program (MSTA) which is run by the MU soil testing lab. According to their website, MSTA is an organization established to ensure that the results provided by participating public and private labs are statistically allowable.

The MU soil testing lab director, who serves as the state program coordinator, evaluates data sent in from labs seeking accreditation to guarantee customers accurate results.

As a leader in Missouri soil testing, MU handles the majority of testing with two operating labs. The first lab is based in Mumford Hall at the University of Missouri and deals with samples from the northern half of the state, as well as the Kansas City Metro Area.

A second lab located at Missouri University's Delta Research Center in Portageville handles samples from the southern half of the state, including the St. Louis Metro Area. Both labs perform services other than soil testing; these services include: plant tissue tests, greenhouse/nursery soil-less growing media, compost tests, and water testing.

MU defines a soil test as that which measures the relative soil fertility levels -- a basic tool in planning a fertility program. When it comes to the season for soil testing, MU calls for winter, as it is the time when soil is lying idle, and leaves an adequate amount of time to plan for fertilizer and limestone application decisions.

For each sample given to MU, four crops of any combination may be chosen, along with their yields in terms of bushel per acre.

Tests that MU offers starts at the general analysis, which test for the soil's fertility. This package includes: pH tests, neutralizable acidity, phosphorus levels, potassium level, calcium level, magnesium, organic matter, and cation exchange capacity. Cost of the general analysis is ten dollars, but other tests on micronutrients, sulfur, and salt content are available to b added for costs ranging from four to twenty dollars.

A coring device is recommended by MU to be purchased in order to receive a quality sample. According to the MU soil testing website, the first step to taking a soil test is; to obtain a six to seven inch core with the coring device, then discard organic matter on top of soil, thirdly, put the six to seven inch soil core in sampling bucket, and finally discard soil below six to seven inches.

Samples should be collected from separate areas, selected by using a field map that may be obtained from FSA or a county soil survey.

There should be 15 to 20 separate core samples from the different cities, with a single representative for each site. For each composite sample, avoid sampling areas with obvious differences of soil color and texture, slope, crop rotation or fertilizer, lime and manure applications.

To create a composite sample, mix the 15 to 20 separate cores in a clean plastic pail, as metal pails contaminate the soil with micronutrients, keeping a one pint sample for the MU sample box, that can be obtained free from your local University Extension center. A composite sample should not represent more than 20 acres.

Once composite samples have been gathered and packaged, there are two options of submission.

The first, and preferred method, is to take the sample to a local county extension center. A second method for submitting a sample is to mail it directly to the sample directly to the MU labs. If mailing the sample, a package must include an information form. These forms should be filled out accurately for proper fertilizer recommendations and should include county name to mail the soil test results to the appropriate area agronomist or horticulturalist.

Samples should remain in boxes or bags that are permitted by MU, with a serial number found on the information sheet, written on the container. According to the MU website, turnaround time is within one to two business days once package is received.

Specific interpretation of results from a soil test can be found in the "Soil Test Interpretations and Recommendations Handbook," located on the MU website. It may include the soil test fertility results, general analysis results, sample identification and field information that was provided to the university.

Contact Ashton Clark at aclark@marshallnews.com