SAMUEL: The truth about soils nutrients and plant nutrition for deer


It’s bow season and so for the next few weeks I’m going to write about deer.

 Even though some of my deer hunting readers don’t believe in scientific research, I do, and so the articles will be based on the latest science.

 For those readers who don’t understand the last sentence let me give my thoughts.

 Some hunters only believe what they see in the woods. They might have only seen it once. They might have only seen it on their property, they might have seen it in mid-summer or late winter, but to them it is gospel and no science based on large data sets will change their mind. Actually I find that sad, but it happens a lot.

Hunters spend a lot of money putting soil nutrients on their hunting lands to improve the nutrients needed for growth of deer.

 Dr. Craig Harper is a professor at the University of Texas and knows more about this topic than anyone alive. He and his graduate students have done numerous research projects on how to manage forests for deer, especially studies on how to get good deer foods growing there.

He looked into the question of whether improving soil nutrients actually translates into better forage nutrition for deer.

 He looked at 11 deer forage plant species in 12 states with a wide range of soil quality. He was particularly interested in crude protein, potassium, phosphorus, and calcium.

 Did the availability of these nutrients in plants and the amount of growth of these plants vary with soils? I won’t go through the analysis, but the results were surprising and conclusive.

 Soil quality had almost no relationship to forage quality. Soil productivity did not alter plant nutrients in pokeweed, sumac, ragweed, and many other tested species. Soil nutrients are a weak predictor of forage nutrients.

 Who knew? The nutrients in those plants did not vary at all. Each plant species had the same macro and micro nutrients regardless of soil type.

What quality actually changes is the plant yield. So you can fertilize or add nutrients to the soil and it doesn’t change the plant nutrients, but it does change the amount of forage you get for each species.

 Farmers improve soils for their fields all the time, and this gives them more alfalfa, or whatever species they are growing.

Dr. Harper is a major proponent of managing forests and fields for forbs for deer. Forbs are not grasses, but rather are herbaceous flowering plants. Some are labeled as “weeds,” but deer love forbs.

 Forbs are non woody and usually have broad leaves. If it isn’t grass and if it doesn’t have woody stems, then it is probably a forb.

Bees love forbs and go to their flowers. Monarch butterflies go to milkweed, which is a forb.

 Ragweed is another common forb. Ragweeds are not a farmers friend, but in the summer deer eat a lot of ragweed. You can plant all the food plots you want, but if you improve your forest areas, you’ll get more pounds per acre of forbs than whatever you planted in the food plots.

Harper has done a lot of work with fire to improve forb yields for deer. Cutting trees can also do that.

 Just remove non-native trees and shrubs and more sunlight will hit the ground and forb yields will shoot up. This approach can also allow white oaks to produce more acorns for deer.

 Harper believes that it’s a lot cheaper to use fire to increase forest forbs than it is to plant food plots.

 It’s easier and cheaper and you get more high quality food for deer. The vast majority of eastern forests could stand to be improved for deer by adding skylights, and the same is probably true of most of the forested cover where you hunt.

Unmanaged forests quickly become shady and unproductive for deer.

You’ll be biting off too much at once if you dive in and try to apply timber improvements to every acre of forest you hunt. Be strategic. Select small stands or patches to tackle each year.

 Use this approach and Dr. Harpers idea of managing for high-quality forbs, rather than worry about soil minerals, relative to deer getting adequate nutrition works.

Dr. Samuel is a retired wildlife professor from West Virginia University. His outdoor columns have appeared, and continue to appear, in Bowhunter magazine and the Whitetail Journal. If you have questions or comments on wildlife and conservation issues, email him at