Does soil quality affect deer size

[BenAllgood]

Interesting podcast covering some of the more recent studies regarding soil quality and deer size. Skip to about 19 minutes to get to the meat of it.
http://huntingtheland.podbean.com/e/64-does-soil-quality-effect-deer-size-a-review-of-science/

 

[SwampCat]

I dont have unlimited data - so give the cliff notes please. I thought a number of studies proved years ago that soil fertility was a dig determining factor related deer size

 

[yoderjac]

Overlay the soybean and corn production map with the P&Y and B&C record locations and you will find a huge correlation. If you are talking about body size, there are other considerations. Before we started moving deer around, large bodied deer were found in the north and small bodied deer were found it the south. This is largely a genetically based phenomenon as deer evolved to match their environment. Large bodies retain heat better in the winter and small bodies cool quicker in the summer. This is known as Bergmann's rule.

Of course, this has to be balanced with nutrition. Nutrition is largely driven by soil fertility.

Thanks,

Jack

 

[BenAllgood]

I dont have unlimited data - so give the cliff notes please. I thought a number of studies proved years ago that soil fertility was a dig determining factor related deer size

Basically, they talked about nutrition being a major factor on size. And, correlation does not necessarily equal causation.

Recent studies sampled forages across a large portion of the whitetail's range. They found that the nutritional level of the same forages to be pretty much equal across the range for the same plant species. So, a new leaf on a ragweed plant has the same nutritional quality no matter what soil it grew on.

The quantity of highly nutritious plants is higher in better soil quality regions, but the quality of the same exact plants are the same.

Soil does not determine the quality of the plants nutritional level. Soil determines the quantity of those high quality nutritional plants.

Put wild deer in pens from different soil quality regions, and in a few generations, the size of those deer is pretty much equal after being given the same diet.

So, areas that have high quality soils do typically produce larger deer, but not because of the soil itself. It's because of the quantity of nutritional forage available.

That's all I can think of right now.

 

[Native Hunter]

Great summary Ben.

 

[weekender21]

I dont have unlimited data - so give the cliff notes please. I thought a number of studies proved years ago that soil fertility was a dig determining factor related deer size

Basically, they talked about nutrition being a major factor on size. And, correlation does not necessarily equal causation.

Recent studies sampled forages across a large portion of the whitetail's range. They found that the nutritional level of the same forages to be pretty much equal across the range for the same plant species. So, a new leaf on a ragweed plant has the same nutritional quality no matter what soil it grew on.

The quantity of highly nutritious plants is higher in better soil quality regions, but the quality of the same exact plants are the same.

Soil does not determine the quality of the plants nutritional level. Soil determines the quantity of those high quality nutritional plants.

Put wild deer in pens from different soil quality regions, and in a few generations, the size of those deer is pretty much equal after being given the same diet.

So, areas that have high quality soils do typically produce larger deer, but not because of the soil itself. It's because of the quantity of nutritional forage available.

That's all I can think of right now.

Putting more hunting myths to bed. Gotta love research. Of course there are some that will never believe any of that information.


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[SwampCat]

Putting more hunting myths to bed. Gotta love research. Of course there are some that will never believe any of that information.


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I dont know that it put a myth to bed if they are still saying deer are generally larger in areas of better soil. They have been saying that for years. Maybe they are changing the specifics, but it sounds like the end result is still the same?

 

[Natty Bumppo]

What myth did it put to bed? Sounds like the research supports what has largely been said all along.

Besides the trends Ben summarized...1) two different plants of same species growing in poor vs. good soil will have the same nutritional value and 2) better soils do produce higher quality plants....better soils also have higher turnover. That is, even though a ragweed leaf on poor soils is as nutritious as one on good soils, good soils can produce 10x the amount of those leaves in the same time period as those on poor soils.

 

[BenAllgood]

The research promotes what we're doing as habitat and wildlife managers. We can't do a broad scale, all inclusive soil quality change across our entire piece of ground. But, we can manipulate the landscape so the "quantity of quality" is greater. It can make us take a closer look at our landscape to see if we're squeezing all of the wildlife benefit out of it that we can. Those forgotten corners of our habitat charge can be improved upon. We can ask ourselves if the nutritional plane of our grounds can be raised by some type of habitat manipulation.

I don't know how many people have done or witnessed a browse survey before. A line is placed for a certain distance across a random area. Plant species and amount of browse are determined. Under a closed canopy, that transect line looks a lot different than in an area that has had recent TSI work done.

 

[FarmerDan]

I couldn't listen to the podcast. Ben did a good good of summarizing. Yoder did a good job in his summary.

Sometimes the "facts" we use to understand what goes on around us, these might be true or not. If they are true, we will often assume a straight-line connection. If we do this then that will happen. I'm not sure, but maybe the myth here is, if we improve our soils we can grow bigger deer, however you want to define bigger. Fact or myth?

That you will find bigger deer where there are better soils is a fact. There is a correlation, but, it's not necessarily true that high quality soils (alone!) cause bigger deer.

For those who ask what's the point of the research, its simply to add to the understanding of something we might already know - or not know. I didn't listen to the podcast and I don't know how the presenters framed the issue.

NRCS is the agency responsible for mapping soils and determining characteristics related to a whole host of land uses. Soils are classed as "prime" if they are superior for agriculture production. If we made a map of those prime soils and put on top of it a map where the big deer live, you would see the two are connected, or correlated. But, you would also see prime soils are located where suburban development is high.

While high quality soils are necessary to produce high quality forage, there are whole host of other conditions required to improve the probability of finding a big deer.

https://www.arcgis.com/home/item.html?id=9708ede640c640aca1de362589e60f46

https://en.wikipedia.org/wiki/Prime_farmland

 

[bigbendmarine]

Somewhat a repeat of what Ben shared, but at the end of the audio they shared these 3 recap points. I share again only because they speak a bit to herd size management that I didn't pick up in Ben's post (and beg pardon if I overlooked it!).

1) If you're in a region with good soils and crops, you'll be able to support more healthy deer per square mile due to higher quantity of available biomass

2) If you're on a site with poor soils you can impact the size of your deer by increasing nutrition through sound land management practices AND by decreasing the number of deer in the local herd so you're increasing the amount of biomass available to a smaller amount of deer

3) It takes time / generations for changes (body size and horns) to be seen in deer herd -- as much as six years. The first generation to receive increased nutritional gain see a relatively modest level of body weight gain (9 pounds weight / 5 points or so of antler changes), whereas the 2nd generation receiving optimal nutrition gained approx 30 lbs, and the deer in the poorer soil quality area gained up to 30 or so antler point improvements, evening out antler size with deer from rich soil areas.

 

[Baker]

Somewhat a repeat of what Ben shared, but at the end of the audio they shared these 3 recap points. I share again only because they speak a bit to herd size management that I didn't pick up in Ben's post (and beg pardon if I overlooked it!).

1) If you're in a region with good soils and crops, you'll be able to support more healthy deer per square mile due to higher quantity of available biomass

2) If you're on a site with poor soils you can impact the size of your deer by increasing nutrition through sound land management practices AND by decreasing the number of deer in the local herd so you're increasing the amount of biomass available to a smaller amount of deer

3) It takes time / generations for changes (body size and horns) to be seen in deer herd -- as much as six years. The first generation to receive increased nutritional gain see a relatively modest level of body weight gain (9 pounds weight / 5 points or so of antler changes), whereas the 2nd generation receiving optimal nutrition gained approx 30 lbs, and the deer in the poorer soil quality area gained up to 30 or so antler point improvements, evening out antler size with deer from rich soil areas.

Between you and Ben this is a good summary. I have not listened to this particular podcast but I'm familiar with the information. What can it mean to us as managers?
Thru habitat manipulation and food plots we can increase the density of nutrition even in poor soils. This creates the opportunity for carrying capacity to increase. Then the incredible power of mathematics comes in to play. If hypothetically , 10% of the bucks in an area have the potential to reach 160" and because of lessor availability of effective nutrition there are only (10) bucks, then only one might reach 160. By increasing carrying capacity where now there are 30 or 40 bucks...its easy to see what happens. This also shows how vital high fawn recruitment is.

And I believe historically this is what has had a big impact on the correlation between B&C bucks in the soybean belt. Higher deer numbers on quality nutrition equals more trophies. Interestingly with management being employed on a larger scale around the country we are seeing more top end trophies popping up everywhere. There are microcosms of big bucks consistency popping up across the country where managers have increased the carry capacity by improving a greater % of the property.

 

[Mortenson]

Crops are probably pretty key. I don't think the soil quality has to be very good, just good enough. Top A+ dirt doesn't seem to be all that important. Look at the far South Central area of Iowa, considered maybe the best trophy deer spot in the world. It also has the worst soil in the entire state. But it has good terrain, and the dirt is good enough to grow crops. I think the myth busting mentioned here is that the deer aren't getting all loaded up on better minerals from the plants grown on that soil. Just more plants. That's how I see it anyway, but I didn't listen to the podcast yet. I've actually never listened to one.

 

[weekender21]

What myth did it put to bed? Sounds like the research supports what has largely been said all along.

Besides the trends Ben summarized...1) two different plants of same species growing in poor vs. good soil will have the same nutritional value and 2) better soils do produce higher quality plants....better soils also have higher turnover. That is, even though a ragweed leaf on poor soils is as nutritious as one on good soils, good soils can produce 10x the amount of those leaves in the same time period as those on poor soils.

Have you never heard someone say that "our deer are bigger due to restocking efforts from XXXX big buck state"? That, at least from a scientific perspective, isn't accurate. Maybe it would be for a year or two but that big antler genetic perspective won't be realized if nutritional demands can't be met. There are obviously many factors that contribute to genetic potential in a given deer herd or specific neighborhood. However, it's nice to know that you can have an impact by improving the quality of your habitat. And, that impact can be magnified if 1) you control a lot of land and/or 2) your neighbors are onboard.

 

[Natty Bumppo]

Have you never heard someone say that "our deer are bigger due to restocking efforts from XXXX big buck state"? That, at least from a scientific perspective, isn't accurate. Maybe it would be for a year or two but that big antler genetic perspective won't be realized if nutritional demands can't be met. There are obviously many factors that contribute to genetic potential in a given deer herd or specific neighborhood. However, it's nice to know that you can have an impact by improving the quality of your habitat. And, that impact can be magnified if 1) you control a lot of land and/or 2) your neighbors are onboard.

Ah, I see what you're saying. No, I have never heard that myself. I live in an area of US that has some of the poorest soil in the country, and where most hunters have a "if it brown it's down" mentality. Seeing and/or taking big deer is a rarity.

 

[S.T.Fanatic]

I don't agree with this 100%. Do some research on what BRIX is and how to increase it. The higher the brix level the more nutrient dense the food will be. More nutrient dense food leads to healthier animals. Animal health leads to heavier or lighter animal as well as bigger or smaller antlers. Fields with high brix level crops will also be free from pests. When a plant has a high brix level it keeps the nutrients in the plant and/or puts it back into the soil through the secretion of sugars through the roots that feed the microbes. Crops with low brix levels secrete enzymes through the leaves in turn losing plant nutrition and attracting pest to the plants.

Nitrate management is huge when it comes to "sweeter" crops. Lower available nitrogen leads to increased levels of sugar. This is why in production sugar beet fields they want the beets to be starved of nitrogen before they harvest.

 

[Baker]

I don't agree with this 100%. Do some research on what BRIX is and how to increase it. The higher the brix level the more nutrient dense the food will be. More nutrient dense food leads to healthier animals. Animal health leads to heavier or lighter animal as well as bigger or smaller antlers. Fields with high brix level crops will also be free from pests. When a plant has a high brix level it keeps the nutrients in the plant and/or puts it back into the soil through the secretion of sugars through the roots that feed the microbes. Crops with low brix levels secrete enzymes through the leaves in turn losing plant nutrition and attracting pest to the plants.

Nitrate management is huge when it comes to "sweeter" crops. Lower available nitrogen leads to increased levels of sugar. This is why in production sugar beet fields they want the beets to be starved of nitrogen before they harvest.

Interesting consideration. I use a brix refractometer in my garden all the time and can measure increases in nutrient density from soil inputs. Seems logical same would be true in habitat at large. I wonder if the comparisons were done on native forbes which may respond to soil differently than introduced cultivars? Once again though supports the idea that we can manipulate habitat even in areas of poor soil to achieve the same outcomes as areas naturally stronger.

 

[SD51555]

I don't agree with this 100%. Do some research on what BRIX is and how to increase it. The higher the brix level the more nutrient dense the food will be. More nutrient dense food leads to healthier animals. Animal health leads to heavier or lighter animal as well as bigger or smaller antlers. Fields with high brix level crops will also be free from pests. When a plant has a high brix level it keeps the nutrients in the plant and/or puts it back into the soil through the secretion of sugars through the roots that feed the microbes. Crops with low brix levels secrete enzymes through the leaves in turn losing plant nutrition and attracting pest to the plants.

Nitrate management is huge when it comes to "sweeter" crops. Lower available nitrogen leads to increased levels of sugar. This is why in production sugar beet fields they want the beets to be starved of nitrogen before they harvest.

There could be a lot to that, and it's worth considering. I had a buddy send me an article a few weeks back talking about how CWD prions can be killed or stifled in humus or humic rich soils. It got me to pondering if the CWD endemic zones don't overlay primarily ag areas.

 

[yoderjac]

The research promotes what we're doing as habitat and wildlife managers. We can't do a broad scale, all inclusive soil quality change across our entire piece of ground. But, we can manipulate the landscape so the "quantity of quality" is greater. It can make us take a closer look at our landscape to see if we're squeezing all of the wildlife benefit out of it that we can. Those forgotten corners of our habitat charge can be improved upon. We can ask ourselves if the nutritional plane of our grounds can be raised by some type of habitat manipulation.

I don't know how many people have done or witnessed a browse survey before. A line is placed for a certain distance across a random area. Plant species and amount of browse are determined. Under a closed canopy, that transect line looks a lot different than in an area that has had recent TSI work done.

I like that "Quantity of Quality" perspective. It helps us get a better handle on what is realistic and deflates the commercialized trend that food plots are the answer to bigger, healthier, larger antlered deer. First, if one does not have sufficient scale, forget trying to impact the herd. Simply focus on making your ground more "huntable", whatever that means given your personal goals.

If you do have sufficient scale, large scale project that are budget neutral or positive have the largest impact in general. Timber management is key. Creating timber management units of different successional stages of timber and using tools like controlled burns creates income while having the largest "quantity of quality" impact on the herd. Keeping in mind that deer are browsers, and a small portion of their diet is tied to our food plots, it is clear that the underlying dirt is the limiting factor in most cases. Timber management can maximize the "quantity of quality" food produced by this dirt and the majority of their diet.

The primary role of food plots in deer management is to cover specific gaps left by the cyclic quality of nature. We know that in the south many native quality foods dry up in the heat of summer and in the north quality food becomes scarce during the worst of winter. We can help fill some of the dips in nature, but we can't defeat the limitation based on our soils.

In most areas the first limiting factor for antler size is age. That is why we let young bucks walk. But how large/old should we let them get before harvesting them? Again, it goes back to the quality of your dirt. Rather than selecting some arbitrary size, we can take inventory and say that we are going target the top 5%, 10%, or 15% depending on the goals for your property. This keeps hunting interesting with a realistic chance of harvest, recognizing the limits of ones dirt, while allowing a nature age structure to redevelop.

Thanks,

Jack

 

[weekender21]

Good points Jack, we’re definitely missing the boat entirely if we jump strait to the food plot conversation. I’d be interested to know what percentage of landowners overall (not this forum) spend any time or give any thought to “managing” deer outside food plots and corn feeders. I’d guess that number would be shockingly low.


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