By Hollis Ayres
As hunters and managers become ever more knowledgeable about the sciences and practices of deer nutrition and management, they sometimes take for granted that folks who are just starting out understand the basics. Winning programs, whether they’re in sports, business or any other endeavor, all have at least one thing in common: periodically, they all go back and review the fundamentals—those things that serve as the bedrock of success. Let’s take a look at some basic terms in deer nutrition and management and what they mean.
As hunters and managers become ever more knowledgeable about the sciences and practices of deer nutrition and management, they sometimes take for granted that folks who are just starting out understand the basics. Winning programs, whether they’re in sports, business or any other endeavor, all have at least one thing in common: periodically, they all go back and review the fundamentals—those things that serve as the bedrock of success. Let’s take a look at some basic terms in deer nutrition and management and what they mean.
WHAT IS “DEER NUTRITION”?
I’ll start with this one for two reasons. First, it’s why as deer “managers” we do what we do. And we are managers, at least when our goal is to improve the quality of the deer we hunt. Second, it’s the longest one to explain. So, let’s get started.
“Deer Nutrition” in a Nutshell. For our purposes, “deer nutrition” simply means how we supplement the diet Mother Nature provides, and in specific ways, to help deer reach as much of their genetic potential as possible.
Whether we’re talking about humans, deer or any other animal, nutrition for our purposes can be generally defined as nourishment through food intake, or diet. And in humans and deer alike, there are two types of diets: general and specific. A general diet is just one that must provide enough nutrients to allow the animal to grow into adulthood and live a healthy, active life. The general human diet consists of three meals a day, each containing something from each of the “four food groups,” and most humans can get enough of what they need right from a grocery store to stay fat and happy. A specific diet is one that is goal-oriented and that goes beyond the general diet. Examples are the body builder who eats a highprotein diet following each workout, or the long-distance runner who eats a carbohydrate-rich meal before a marathon.
The “Goal” of Deer Nutrition. Generally speaking, the goal of deer nutrition is to supplement what nutrition Mother Nature provides in amounts, quality and availability needed for deer to maximize health, body size and antler size. There are two reasons why this is necessary in most cases if deer are to maximize their genetic potential: the specific physiological needs of deer, and shortfalls in naturally available food sources.
Specific Physiological Needs of Deer. Deer are “small ruminant” animals. A ruminant is an animal whose stomach has four chambers, one of which is the rumen. The rumen is home to millions of microorganisms that do the bulk of digestion. Cattle and deer are ruminants. However, the rumen of a deer is much smaller than those of cattle, and as a result a deer cannot effectively utilize stemmier, tougher forages the way cattle can. Compare the mouths of cattle and deer, and you’ll see a major difference: cattle have wide mouths, which are ideal for grazing, but deer have long, slender mouths, which allow them, as “concentrate-select feeders,” to pick and choose only the most tender leaves, shoots and buds that are compatible with their small ruminant digestive system.
Changing Nutritional Needs. Consider also that the nutritional needs of deer change during the year. For example, in the spring and summer, protein is the king of nutrients, and minerals might be considered the prince. Large amounts of protein and minerals are needed by bucks for antler growth and by does during the last trimester of pregnancy and later when they’re producing milk for newborn fawns. During fall and winter, though, energy takes top billing. Energy, which is actually a product of nutrients, is provided by fats, lipids and carbohydrates.
Shortfalls in Naturally Available Nutrition. To make matters even more nutritionally stressful for deer, the food Mother Nature provides is often of limited palatability and duration. The tender new growth of early spring quickly becomes stemmy and less palatable to deer, and at some times of the year may be totally exhausted. An example is the period from late winter until spring green-up before natural forages re-emerge.
While naturally available food sources are sufficient to keep deer alive in most cases (but not all), it’s usually just enough for them to get by. In our context, then, deer nutrition simply means providing deer with regular access to the specific nutrition they need throughout the year to not only remain healthy and active but also to maximize body weight and antler size.
Our goal is to help deer thrive as opposed to just survive.
WHAT IS “SOIL pH” AND WHAT DOES IT MEAN?
Of all the basic terms used in deer management, “soil pH” has historically been the least understood. Part of that is the fault of experts who unnecessarily complicate their explanation to folks who are just starting out in deer management. The good news is that for our purposes, “soil pH” is very easy to understand:
What Soil pH “Is.” Soil pH is a set of numbers from 1-14. The center of the range (6.5 – 7.5) is referred to as “neutral” soil pH, lower numbers indicate “acidic” soil, and higher numbers “alkaline” soil.
What soil pH “Means.” Most high-quality deer forages grow best in neutral soil pH. When planted in soils with a soil pH outside the neutral range, these plants cannot access all the fertilizer you put out. In other words, if you fertilize and plant in soil with low soil pH, some of the fertilizer you put out is being wasted.
Here’s an analogy that may open your eyes: think about your car or truck. Hopefully, the gas tank doesn’t leak. If it doesn’t leak, then all the gas you spend your money for is going to be used by the engine. If you poke a little hole in the bottom of the gas tank, though, some of the gas will leak out and be wasted. And if you poke a few more holes, the gas will leak out even more quickly and even more will be wasted. You might as well have bought the lost gas and poured it right down the drain for all the good it will do you.
Soil pH works means the same thing, but applied to your food plot. The farther out of neutral your soil pH, the more fertilizer is being completely wasted because the plants can’t access it.
How do you correct the problem before you plant? Read on.
WHAT KIND OF LIME AND FERTILIZER SHOULD I USE?
The way to raise the soil pH of the soil in a plot with acidic soil is to add and incorporate lime into the seedbed by disking or tilling. By “lime” I mean natural, mined Calcitic or Dolomitic limestone in either “ag” form (rough crushed) or “pelleted” form (more finely ground, and suspended in clay balls for ease of use in a broadcast spreader). More and more, we’re seeing new products come on the market and other “lime substitutes” that purport to raise soil pH as well as limestone, and in far less quantities pound-for-pound than limestone. Some of these may have merit. Others almost certainly do not. And still others present risks not associated with lime.
Other products we’ve seen purport to raise soil pH and fertilize the seedbed correctly, all out of the same bag! Some of these are also suspect, first in that they suggest that a comparatively tiny amount of liming material can substantially raise soil pH, and second because the fertilizer portion is a fixed blend, meaning that you can’t adjust nitrogen, phosphorous or potassium individually, which may cause you to go either low or high on one or two elements, wasting the excess to get enough of the other.
So, how much lime do you need to add if your soil pH is below 6.5-7.5, and how much and what blend of fertilizer do you need to add? Lime works to raise soil pH by acting in particle-to-particle contact with the soil. That’s why you often see lime recommendations in soil test reports expressed in tons of lime per acre; there are a lot of dirt particles in the top few inches of an acre! As for fertilizer, different types of plants have different fertilizer requirements. There’s only one way to know specifically how much lime and fertilizer you may need: with a soil test performed by a qualified soil testing laboratory.
Again, if you get nothing else out of this article, please at least get this: Performing a laboratory soil test is the most important thing you can do to ensure a successful planting and save money. A soil test performed by a qualified soil-testing laboratory costs only about $10. For that $10, the lab can tell you whether you need to add lime and fertilizer, and if so exactly how much so that you don’t waste money, and exactly what blend of fertilizer to use to optimize forage growth. Again, only a laboratory soil test gives you all that. Inexpensive do-ityourself testers may not be consistently accurate, are prone to user error, and cannot provide exacting recommendations for that specific plot.
Let me put it this way: Would you spend $10 if you knew you’d likely make a few hundred dollars back? A laboratory soil test can save you literally hundreds of dollars in needless lime and fertilizer expenses. And if you do need lime and fertilizer, it can keep you from buying anything more than exactly what you need. And this doesn’t even mention the greatly improved growth and attraction of a food plot planted after following the recommendations of a real soil test.
MOST IMPORTANT INFORMATION ON A LABORATORY SOIL TEST REPORT
Although the scientific process for generating the information on most laboratory soil reports is similar, the form in which that information is provided is not. To help you wade through your report, realize that some of the information is critically important to you as the planter, and other information is only important to the lab.
The most important information to you as the planter are (A) the lab’s readings of your soil’s soil pH and nutrient content, and (B) the lab’s recommendations for correcting soil pH and adjusting nutrients when necessary.
Soil types differ from one plot to the next, and some acidic soils, for example, are able to “hold” neutral pH longer than others once lime has been incorporated. Likewise, not all forages have the same fertilizer requirements. Recommendations can also be affected by the amount of organic matter in the soil, CEC reading and other factors. The point is that soils differ, and only a lab can give you a recommendation based precisely on the type of soil in your plot.
WHAT DO THE NUMBERS ON A FERTILIZER BAG MEAN?
When you look at a bag of fertilizer in a store, you’ll see (usually right on the front) three numbers separated by dashes. Examples are “13-13-13” and “6-24-24”.
What the Numbers Stand For: From left to right, these numbers stand for nitrogen (N), phosphorous (P) and potassium (K). These are the “big three” — farmers often refer to these as their “NPK requirements,” and they’re usually the only nutrients you’ll need to concern yourself with when planting and maintaining a food plot. (Lime is arguably even more critical, but it is not a nutrient.)
What the Numbers Mean: Each number represents the amount of that nutrient (N, P or K) in 100 pounds of that fertilizer product. For example, if you see a 50-lb bag of “6-24-24,” you’ll know that inside that bag are three pounds of N, and 12 pounds each of P and K.
How That’s Useful To You: Just knowing that can help you select a blended fertilizer product, or multiple blends together, to meet the recommendations specified in your soil test report. And in some cases, it can even help you save money. For example, let’s say you will be planting Imperial Whitetail Extreme, and your soil test says you need to fertilize at planting with 40 lbs. of N, 40 lbs. of P and 40 lbs of K. When you go to the store, you see that they have “10-10-10” and “20-20-20.” Which one should you buy?
Since you know that each number represents the pounds of that component in 100 pounds of the fertilizer blend, you know that by putting out 400 pounds of 10-10-10 you will be putting out 40 pounds each of N, P and K (4, as in 400 pounds, times 10, the content of each component in the blend). But, you can do the same thing with only 200 pounds of 20-20-20 (2, as in 200 pounds, times 10, the content of each component in the
blend).
Realize also that while you want to be as precise as possible, you don’t have to be mathematically perfect — just get as close as you can, and if you have to go “over” on one component to get the needed amounts of the other two, it’s usually okay to go a little over on nitrogen if you are fertilizing in the fall.
WHAT DOES IT ALL MEAN?
It’s been over 20 years since the Whitetail Institute started the whole food plot and deer nutrition revolution. Since then, the sciences and practices we now refer to collectively as quality deer management have proved a huge success. According to the record books, hunters today are five times more likely to harvest a record-book trophy buck than they were in the late 1980s. As advanced as deer management has become, and will likely continue to be in the future, it always pays to make sure your basis is solid. If you have any questions about these, or any matters related to deer, deer nutrition, food plots or deer hunting, call the experts at the Whitetail Institute at (800) 688-3030.
