Bunkey used to have a war against ants, that is, until he did a little reading about them. He wanted to know how to get rid of them then found out how beneficial they actually are.

Ants represent almost half the insect population. (I wonder who counted). Ant nests cause a loosening of soil that increases soil aeration from all the tunnels they make. This increases water infiltration and heightens the soil moisture content. The result is that there is more moisture available for plants so they can increase their nutrient uptake. This helps the plant to have higher rates of photosynthesis and transpiration leading to a healthier plant. The increased soil aeration also promotes microbial activities in the soil.

Ants enrich the nitrogen in soil. Bacteria in the ant’s gut help to fix atmosphere nitrogen (ant poop?). During nest construction these gut bacteria are transferred to the soil thus making topsoil and subsoil high in nitrogen. We all know that nitrogen helps plant growth and development.  Leftover plant parts and decayed materials carried in for the ants for food and thrown out of the nest enrich the soil’s organic carbon and other organic matter.  The little stinkers also maintain neutral PH of the soil. Somehow they alter the soil chemically.

For decades, soil health has deteriorated under erosion cause by farming and other land use. Reduction in soil residue cover, deforestation and other factors reduce soil health. Ant nests can be used as a bio-indicator in rural areas to confirm the health of the soil. Many nests tell you that the soil is in good health.

Your local nursery and the big-box stores have piles of bags of composted manure. The nutrient content varies greatly. It depends on the animal, bedding storage and processing.  Poultry manure compost is usually higher in nitrogen. It is all good for your garden. The problems arise as to how much you should apply. Too little leads to nutrient deficiency and poor plant growth. Too much can cause excessive vegetation growth. If you are close to a lake, and it is nearly impossible in Otter Tail County not to be, runoff can cause nitrate leaching, phosphorus runoff and a nice thick growth of lake weeds.

Nitrogen content of composted manure can range from 0.5% to about 3% and only about 10% to 15% of that will be available the first growing season. The best results can be obtained by digging it in. If the compost has 1% nitrogen, apply 2 pounds of compost per square foot. The nutrient value should be on the bag along with recommended rates of application.

Dried manure may be available. It may be in pellets. It has been dried to temperatures of 150 to 175 degrees for at least an hour to reduce water content to 10% to 12 % or less. It has a higher nutrient value than the composted stuff but still may have a few pathogens in it.

Never use fresh manure. Not only can you “burn” your plants, the stuff is full of pathogens. Aged manure that has sat for a long time and is partly decomposed may still have pathogens in it.  Wear gloves and wash well before you eat lunch.

Even though ants can be a good thing, you still don’t want to share a house with them.  Watching a battalion of ants marching through the butter will put anyone off their lunch. They have dirty feet!   Spraying around the foundation usually limits invasions.


Bev Johnson is a Master Gardener with the University of Minnesota Extension. Her column appears in the Weekend Edition.

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