Soil testing for nutrients important for production

With the continued high price of fertilizer, 2009 is a year to pay particular attention to fertilizer cost as an important part of the cost of production. The only way to determine the fertility of a field and the actual fertilizer needed is to take a representative soil test and follow recommendations for the crop.

It is important to remember, however, that the results of the test cannot be better than the sampling procedure used to get the test. As you get out to take soil samples this spring remember this: since a pound of soil can represent several acres, you should take samples that depict the area on which you want fertility level information.

The County Extension Office has information on soil testing procedures, sample bags and soil probes you can borrow to take your soil samples.

To obtain a good representative soil sample you should take random core samples at a uniform depth throughout the area. Mix cores together well in a clean, dry plastic bucket; then fill the sample bag and bring it to the County Extension Office. The soil test analysis will be sent to the University of Kentucky Soil Test Laboratory in Lexington where it will be tested. You will receive research-based recommendations on lime and fertilizer requirements for crop or land use.

How many cores should be taken for a soil test sample? If you are sampling a five-acre area, take at least 10 cores; for a 10-acre area take 15 cores, for a 20-acre area take 20 cores. No single sample should represent more than 20 acres.

When sampling a large field, divide it into smaller areas based on soil type, cropping history, or problem areas. Label each area with a letter or number to make record keeping easier.

When collecting soil samples for a home garden or lawn, separate samples according to land use. Take separate samples for a garden, lawn, fruit trees, ornamental shrubs and azaleas because each may have different fertility, acidity or alkalinity requirements. Take at least 10 cores for each separate area and mix them together well.

How deep you go to take cores depends on the tillage system used. Cores from tilled areas should be taken to plow depth, usually 6-8 inches. Take cores four inches deep in no-till fields and pastures. In home lawns, collect cores at a depth of 4-inches. Take cores 6-inches deep for gardens, ornamentals and fruit trees.

Although you can take samples through much of the year, fall and spring are the best times to take them. Don’t take cores when soil is too wet because it is difficult to mix them well and they are hard to handle. The soil should be dry enough to till when you take samples.

When you bring the samples to the Extension Office for processing, you will need to know a brief history of the field and the crop you expect to grow. There is a charge for soil test analysis through the Extension Office. Fees are $4.50 per sample. The LaRue County office offers two samples tested for the same price as one. In other words, the charge for two samples is also $4.50. The fee pays for testing and postage costs. The turnaround time is normally 10-14 days from the date the sample is turned in until the recommendations are received. Turnaround time will depend on the time of year and the numbers of samples submitted to the state lab.

Local farm supply stores also offer soil-testing services. Get your soil tested.