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Wednesday, May 4, 2016

Avoid cooking a soil mess

Thursday, April 2, 2009

Generally there are two different types of attitudes when it comes to cooking.

Either throw the ingredients together by look, feel and taste to measure each ingredient precisely.

When it comes to cooking, it is fun to experiment.

However, soil is entirely a different scenario that can result in one or more season's of heart ache if you make soil amendment additions a guessing game.

A few weeks ago, lime was discussed and the fact that wood or other fire ashes are high in potassium (K) and result in soil pH elevations. It is critical to use care when incorporating soil amendments and to soil test rather than guess when adding fertility to soil.

Many like to add compost or other organic matter to soil to improve soil. At 5 percent organic matter, a soil is black. Most of our soils in the area are not black so there is less than 5 percent organic matter.

A strategy over time to increase organic matter in a soil from 2-3 percent is very significant in terms of soil improvement. Organic matter is responsible for a soil resisting soil compaction and its ability to hold nutrients and water. Like clay, organic matter has negative charge, thereby allowing it to hold nutrients that have a positive charge. One should never add sand to a garden spot as it, when mixed with our native soil types, increases the likelihood of soil compaction and sand is poor for holding water while being incapable of holding nutrients.

The carbon to nitrogen ratio is very important to consider when making soil amendments. When high carbon to nitrogen ratio items are added to soil, plants become nitrogen starved and will remain so for some time. In fact, it is possible that plants would be incapable of surviving.

A ratio of 25:1 or lower is necessary to stay out of trouble. Wood chips, saw dust, etc., has a very high carbon to nitrogen ratio typically 40:1 or more.

A common question is, "can I add mulch, wood chips or saw dust to my garden?"

As long as the material remains on the surface as a mulch weed barrier there should not be a problem. The problem occurs when one mixes this wood material into the soil and soil microbes starve the soil of nitrogen in an effort to decompose the wood product. Legume material is at or below the 25:1 ratio. Legume material would include soybean stover, alfalfa, or red clover materials. Straw has a higher ratio, although less than wood, so it would not be good to mix into soil.

Horse manure is one of the better manures to add to soil. Adding manure to soil for building organic matter requires that care be taken to not add weed seed from straw. Also, horse manure composing large amounts of wood shavings should not be mixed into the soil due to the carbon to nitrogen ratio issues already mentioned. Poultry manure is very rich with nitrogen and can actually burn plants.

The tag on a fertilizer bag has three numbers which are the amount of nitrogen (N), phosphorus (P), and potassium (K). Hence, a bag of 10-4-3 is 10 percent N, 4 percent P and 3 percent K.

Since soils have a negative charge and N is either in a negatively charged form or quickly converted by microbes to a negatively charged state, it is highly susceptible to loss from the soil.

Both P and K are not easily lost from soil if applied at proper rates.

Since one cannot determine by any of the five senses these soil levels, soil testing is critical to know what soil amendments are needed.

Find a list of certified labs at http://www.agry.purdue.edu/ext/soiltest.... and you can get instructions on how to soil test along with borrowing a probe from the local Extension office.

You can contact the local Purdue Extension Office by calling 829-5020 Ext. 14 in Owen County or 448-9041 in Clay County for more information or publication copies regarding this week's column topic or to RSVP for upcoming events. It is always best to call first to assure items are ready when you arrive and to RSVP for programs.