Deer Holding Capacity
I get asked at times how many food plots one should plant. The answer I provide comes after taking a number of factors into play. Here are the areas I look at.
Where are you located? Growing season length varies by location in the US. Heat units also vary according to planting zones.
What is your current deer numbers? If one has 5 deer per square mile versus 100, that is a huge difference in forages needs.
What is planted on adjacent properties? If your neighbors or corn and soybean farmers, that reduces the needs for summer and early fall forages. If the neighbors plant alfalfa and hay fields, that reduces the 365 day nutrition on our properties. If the neighbors don't plant anything, when you do, that will exponentially increase your forage planting acreages.
What is your soil texture? There is a big difference in production capabilities on soils that are sand based versus loam based.
What is your experience? That isn't quite as important and the ability to be flexible and be open minded in one's approach.
A deer will consume between 2.0-3.5% of their body weight in feedstuffs depending on season. A 125 lb whitetail will eat around 3.75 lbs of "dry weight" per animal per day. In a 365 day year that results in around 1600 lbs of total "browse" needed to sustain. This can come from acorns, soybeans, weeds, fruits, food plots and any browse. What I use as a default is 1/3 of a deer's diet from food plots in areas with average browse and average deer numbers. What that means is we need about 500-450 lbs of dry matter from food plots per deer per year. If we are an average food plotter who produces an average level of forages per acre (4000 lbs) you will be able to feed about 9 deer per acre. In areas with larger body weight deer you would feed less than that 9. In areas of the south with much smaller body weights you would be able to feed 11-12 deer per acre.
My goal with clients is to plant smarter and more efficiently. First maximize capacity before doing more. Why plant 3 acres when 2 acres might be enough if you plant smarter. Here is some things to consider. Grains like oats produce 2 ton of forage dry matter per acre. Alfalfa and some annual clovers produce 5-8 ton per acre. Many common brassicas 2 ton per acre where as other multigraze and higher yielding brassicas produce around 3.5-4 ton of forage dry matter per acre.
In the end, you only get out of it what you put into it. An analogy would be with corn. If you provide only enough nitrogen to yield 100 bushels of corn (100 lbs of N), there is no way you will produce 200 bushel corn. If you only put down 200 lbs of 10-10-10 fertilizer on your brassicas, you would be mining your soil even with these lower demand forages.
Nutrition comes from soil fertility not the air. Roots uptake nutrients. If the nutrients are not in the soil, they will not be in the plants. Deer eat to meet their energy requirements. The more nutritious the forages the less total lbs of forage dry matter needs to be consumed per day. This is called efficiency. It is not rocket science but yet it is overlooked by most. A bite of oats is different than a bite of winfred brassica. A bite of balansa clover is different than a bite of berseem clover. My 3rd book will be called the next bite. For those who care to do better, this will be getting to the "root" of deer science.
Food for thought. Be well.