How Crop Conditions Affect Whitetail Activity

How Crop Conditions Affect Whitetail Activity
Crop rotation, plant growth cycles and other factors affect how deer relate to agriculture in an area. And those factors are constantly changing. Photo Credit: Joe Ogden

I stepped out of the truck as the sun crept over the horizon, lighting up the stillness of the countryside. Frost had settled hard through the starry overnight. It was Thanksgiving morning, and as I headed into the timber to pull several trail cameras, I was simply enjoying the morning while being mindful of life’s blessings.

I gazed at the bean field, which sparkled as if encrusted in diamonds. As I rounded the corner of a woods line, I noticed a farmer’s hulking red Case combine parked parallel to a stand of half-harvested double-crop beans. My mind wandered to the life of this farmer who was having trouble finishing the harvest. Rain, freezing temperatures, wind damage and death in his family had made field work trying.

If you’ve hunted whitetails long, you’ve likely seen the importance of being able to read the agricultural “tea leaves.” Here in Illinois, the type of crop planted in a given location in a given year greatly influences when and where deer feed. That, in turn, affects numerous strategic choices I make throughout the season.

Nutritional Value

The term total digestible nutrients (TDN) of a given feedstuff is a basic cornerstone of measuring nutritional value. The higher the TDN, the more energy it provides the animal consuming it.


Because whitetails are concentrate-selective browsers, this term can get overwhelming in its pure calculated form. Suffice it to say TDN can be calculated by adding up the digestible simple carbohydrates, digestible crude fiber and digestible crude protein/crude fat.


In respect to such agricultural crops as corn, soybeans, alfalfa and clover, TDN will change drastically from the day the plant emerges from the ground to the day it’s combined at harvest or mowed for hay. This change is natural and is part of the annual crop cycle.


Another way to think of TDN is a reflection of a plant’s maturity. The older a plant gets, the less digestible it becomes, due to fiber formation. Of course, a whitetail’s TDN requirements also change through the annual cycle. A lactating doe in late summer needs a different nutrient mix than a rutted-down buck heading into the doldrums of winter.

Summer Crop Strategy

Hot weather, growing grain crops and velvet racks all go hand in hand here in the Corn Belt, and summer is usually the first time I make contact with mature bucks. Inventorying specific deer is the name of the summer game, and crops in the area let me make some strategic choices.


To establish visual contact with a mature buck in farm country, look for first-crop soybeans next to timber edges that catch evening shade near sundown. Sometimes a heavy browse line can be seen in the beans in these shaded areas. Either stake out such locations with reliable trail cameras or watch them from long distance, utilizing an observation tree stand or a ground hide. Quality binoculars and/or a spotting scope will be helpful. If trophy bucks live on this farm, they should show themselves in these spots.

Once a big buck has been seen feeding in the beans regularly, study him. Go nightly and “hunt” with your optics or video camera. You might not kill the buck in that location in November, or even opening week of bow season, but you can sometimes get useful information by watching him enter and exit the beans in summer.


Most of the time I view summer corn for the structure or cover it provides, not its food value. I love to place trail cameras on the edge of standing corn where the end rows make a right angle. This is an excellent camera site and is even better if deer are using it to travel to a lush bean field. You can get some jaw-dropping velvet photos in these areas.

whitetail velvet buck feeding in soybean field
In soybean country, during hot weather one of the best spots to scout is a shaded field edge far from human activity.

Corn also helps me access areas of beans or hay without giving away my entry/exit for evening observations. If I have a small field I want to scout from long range, standing corn usually hides me well enough that I can slip in and out, making reconnaissance repeatable without fear of pressuring deer.

Summer forages such as alfalfa and clover offer other excellent inventory opportunities for bachelor bucks. One factor to consider with these perennials is the harvest cycle. Alfalfa is usually mowed or chopped for silage about every 30-40 days, and deer use will typically peak about two weeks into a fresh growth cycle, when TDN of the plant is superior. At sunset in July, nothing looks prettier or smells better than a field full of velvet bucks with freshly mowed alfalfa hay in windrows.

A common summer crop rotation not to be overlooked is the harvesting of winter wheat and the planting of double-crop beans. In my neck of the country, most winter wheat has been harvested by Independence Day. I’ve noted bachelor groups of bucks flooding into the wheat stubble even as the combines are still cutting. The bucks seem to do this out of curiosity, for the most part. These double-crop fields that grow late-maturing, green soybeans will house every hungry buck in the area in August.

Noting these rotational trends well ahead of time provides the hunter ample sources of data to observe from during the velvet months. This is a critical portion of my summer plans when I decide to target a certain buck or two that might have my interest.

September

We’ve all been there. We ogled a giant pounding the beans all summer, got tons of trail camera photos of him and even told our taxidermist to get the knife ready. Then . . . poof. He gone.

September is when this crisis seems to occur. What drives the shift? A lot of it is blamed on shifting of home ranges from hormonal changes associated with velvet peel and the impending fall. But for my money, it’s all agriculture-based.

Food preferences have shifted by now. The TDN of brown soybeans drops off. Corn dries up. It appears the big bucks are all gone, but they aren’t — they’re just lollygagging in the timber, eating greenbriar and falling mast, including white oak acorns and persimmons.

Don’t panic. If your season opens in September, a great early tactic is to move in on bucks holding true to those older summer food sources. Find the shade, find the green, late-planted beans and find the bucks.

If corn is being shelled now, stake out the edges of timber and from a distance, watch the deer pour into the fresh stalks. Then move in for the kill once you’ve spotted a target buck.

October

My October hunting strategy revolves significantly around which crops are left and which ag practices are occurring. By now most grain crops are mature, and the plants have dried. This means the final TDN destination for the crop has arrived. Several other factors that influence farmers also can affect deer hunters this month. Timing of spring planting is a huge factor, as it influences harvest dates. Of course, so does weather during the crop cycle, including copious rainfall and any droughts in late summer or early fall.

In October, I love taking a packable hang-on stand and climbing sticks and running them into areas that hunt very small after the corn comes out. The ninja corn moves can help cover your entry and exits, help dampen noise on entry, and give the mature animals we all dream of a perception of security. If I can find some edge trees in those shaded summer inside-corner camera sites, I’ll crash the party and hunt them.

Does it work all the time? Not even close. Can it work? Indeed. October has long been lamented as having a “lull” for killing mature deer. Hogwash. If there’s standing corn, you can kill. My best archery buck was killed over standing corn on Oct. 10. He was an animal I’d isolated to 4-acre patch of timber surrounded by crop. He lived in this “timber island’ in a sea of standing corn, and the corn helped me kill him.

Another tactic I like to try is what I call the “boomerang buck.” It revolves around standing corn in October usually. If I have a particular buck in mind and if I have had a difficult time locating him after September’s velvet peel and range shift, I watch for combines harvesting in his area. Once harvest begins, and we have all seen it or heard about the farmer who sees it from the combine cab: once the dust begins to fly and corn being shelled, the buck you have been worried about is liable to show up while harvest is going on. I see this a lot. It’s almost like they can’t help themselves. I’ll set up to get a broad overview of the farm as harvest is being completed or going on actively. Usually, this is done with a quality spotting scope and a tripod and chair. If the buck you’re targeting is here, he will usually hit these fresh shelled corn stalks in the first few evenings and “boomerang” back into your life. This works well at also identifying new bucks to make a play on. Patience and mobility are keys here.

As much as I utilize corn in October, I all but abandon standing beans then. Not saying I couldn’t shoot a mature buck over mature, brown beans. It can happen. But I’m more likely to simply disturb the deer.

By October, most all beans have ridden the TDN cycle and are no longer the lush mecca they were for bachelor bucks. When you place your tree stand over beans, you’re likely committing to summer pattern and will often be disappointed in October results. I’ve learned this firsthand.

Nor do beans offer the cover corn can give you for sneaking in close. At dusk, if you exit through a dry bean field, you’ll blow deer all over the place as you snap stalks and trip in planter tracks and stumble in drainage ditches. I’ve seen October deer use brown beans more for shady bedding cover than food. That said, if you can find late-planted double crops that are still green, they can hold some drawing power. But even these beans are all about to be brown soon. Remember this before you commit too deeply.

Farming practices in October can also pinch your hunting plans a bit. In my area, wheat is being sowed, and fertilizer is getting added in those fields. Once the beans and corn are out, a lot of farmers around me will till under their stalks and stubble. This also poses a few negatives for us deer hunters. It’s frustrating to pull into a shelled corn field you’ve staked out and hung stands over, only to have a tractor and chisel plow doing laps till dark.

farm equipment harvesting crops
Crop harvest not only can spook deer, it can radically alter their food supply. Be a step ahead of this predictable shift.

The longer-term effect of tilling under corn stalks and bean stubble is also negative for deer. It renders most fields nearly worthless in winter, compared to non-tilled fall crops. And if you’ve never sneaked through a ripped-up, muddy corn field in late October, it can be a fair workout. Bring your boot scraper!

November

Around the rut, ag practices and crop rotation don’t seem to have a huge impact on bucks here in Illinois, but they affect the does. So if you can find where does are feeding out in the open, a mature buck is apt to get himself killed walking about in daylight scent-checking them. If I crop hunt during November, it’s usually during our firearms season. I’ll sit back and wait on some does to approach a destination cornstalk field to feed and lead one of a few target bucks I might have in a given area in front of me. I’ve taken numerous bucks during the early Illinois gun season using this method.

Crops such as alfalfa can work well for doe attraction as well, unless an early frost has bit the green growth. Once that happens, many forages become far less desirable as food. I’ve seen deer walk through brown alfalfa to get to small, recently logged woodlots that were chock full of greenbriar. The deer in these cases were simply selecting for better TDN in a species of plant that to us might not appear desirable.

Winter Crop Strategy

The final destination of our yearly “farm tour” lies in the rigors of late season. By December and especially January, the rut has dwindled. Bucks and does are tired, have lost weight, and now face bitter cold. All these factors make them desperate for thermal cover and caloric intake. It’s in these two months that local farming practices can be huge positives or negatives for the buck hunter with a tag still in hand.

First and foremost, I find that the location of an ag crop now is exceedingly important. Other factors in the equation are the presence or absence of fall tillage, harvesting efficiency and unexpected weather events that can create what I call a “pop-up” food source. These areas attract bucks because of the simple availability of concentrates during the most energy-demanding time.

The first order of business in late season should be to locate red-hot food sources. I’ve observed mature bucks shifting their winter ranges two to three miles to reflect a food change. A buck’s range will expand a bit now or shift to where he can feed while maintaining close contact with thermal cover. Check any available corn stalks that haven’t been tilled under. Finding a farmer who still runs an older, less-efficient combine is a smart play, as well.

Also be on the lookout for places where flooded fields or crops downed by wind damage have hindered harvest efforts. Any of these factors can combine to form an intense “pop-up” winter feeding area, creating a great opportunity to shoot a mature buck slaving to his stomach. Corn now is king, but don’t neglect beans. A partially standing bean field in late winter can be a focal point for a big winter buck.

Shed hunting is becoming increasingly popular, and the same principles of crop food sources hold true here. If you want to find sheds, look hard at these fields. Cornstalks are of course difficult to locate sheds in, but given the right location, such fields can be paydirt to the person willing to grid-search them.

Last winter, I found a 40-acre patch of corn that had been flattened by wind prior to harvest, leaving thousands of bushels on the ground. Once shed season was in full swing, that field yielded 10 sheds. One was an 80-incher with a 16-inch G-2 tine.

In Conclusion

The sight of that frosty Thanksgiving morning sunrise and the big red combine ready to finish a bean field got me thinking about how difficult farming is. There’s always uncertainty as to how the crop will turn out. In that sense, it isn’t all that dissimilar from our own dreams of shooting a big buck.

No deer season is ever simple, and no season is ever a carbon copy of the last. A farmer’s success is measured in bushels per acre, while a hunter’s can be measured in inches of antler or pounds of venison. Either way, there’s a lot of effort involved — and a lot to be thankful for.

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