Lucky, you are right. I'm not at all opposed to the responsible use of herbicides as one tool to control weeds but my general approach has been evolving over time. Let's start with a definition for the word "weed". A simply one is "a plant out of place". Something growing where you don't want it to grow. So, weeds are very subjective and really depend on your objective.
Farmers traditionally use tillage or herbicides or some combination to control weeds to maximize the yield of a monoculture they are growing. If the yield increase per acre X the price is more than the cost of weed control, the farmer has met his objective (at least in the short run). We sometimes think of ourselves as mini-farmers. There is a lot we can learn from them, but our objectives can be different.
So, my primary objective is to manage to improve the health and age class of the deer herd balanced with managing for turkey and timber income. Another objective is introducing new hunters to the sport. So, in my case there is some overall balancing to do, but for purposes of this discussion, I'll focus on feeding deer.
Deer are browsers, not grazers. Free ranging deer have an amazingly diverse diet and any food plots we plant will only be a fairly small fraction of the deer's overall diet. What I try to do is look for holes; time periods when the vast array of native foods diminish. In the north, this is usually winter and in the south summer. I'm in zone 7a, so our major stress period is summer but we also have some stress in during the winter.
When I first started, I wanted to maximize yield like a farmer. The reality is that given I plant sufficient acreage, unless fields are wiped out completely, the yield is sufficient. Yield still plays a role with me, but not in the way it used to.
Starting with my summer stress period, I tried planting warm season annuals. All the normal stuff. Without the use of herbicides, between heavy browse pressure and heavy summer weed competition, for most plants, a seed turned into a single bite of food for a deer. Basically foods that were attractive did not produce sufficient yield even with 7 acres of warm season annuals. So, here is an example where herbicides save the day for me. I started with Eagle RR forage beans with a light mix of corn (7:1). At smaller acreage, the deer would keep the beans naked all summer but they couldn't seem to kill the Eagle beans. The deer would eat a leaf and the plant would push a new one. By the time I got to 7 acres of it, the beans would canopy, get 6' tall and produce many (but small) pods. A couple years ago, we got our population under control and I've been able to plant ag beans. Last year they canopied. This year our numbers have bounced back a bit. The ag beans did not grow fast enough to canopy so they are full of summer grasses and weeds, but there are plenty of beans in the fields. Many browsed heavily but many not touched. Regardless of the field covered with weeds there is plenty of soybean forage in it. Keep in mind if someone were planting beans for pod production up north, one would need to evaluate whether the weeds stopped sufficient yield of pods for the winter. Here, deer mostly ignore my pods unless there is a complete mast crop failure so pods don't matter much to me for deer.
When we turn to fall, I have small harvest plots and some larger plots. These all have a clover base. The 7 acres of beans have a cover crop surface broadcast into them when they yellow which provides fall/winter food. So, lets talk about clover. I used to want beautiful monocultures of clover. It was expensive in both time and money but they looked great. It was all fluff. I've found that many of the broadleaf weeds in my clover are great deer food. Therefore , those are not weeds to me. Since my beans cover our major stress period of the summer, I count largely on the clover for spring and fall. I do my best to start with a clean field when planting clover. I like to use buckwheat to get good control of weeds during the summer and then surface broadcast Durana clover with a nurse crop of Winter Rye. I use the throw and grow approach Crimson N Camo discusses. This is good for the soil (I'll talk about that later) but it does not bring up more weed seed into the germination layer. Durana is slow to establish so timely spring mowing is important. Each time the WR reaches about a foot, I'll mow it back to 6". Once established, I treat my clover very differently. I mow it once in the spring to release it from the weeds. I then let the summer weeds take over. Sometimes my clover fields have 6' tall weeds during the summer. They shade the clover from summer heat. Right before our season, I'll mow them back to 6". There is lots of great clover growing under the weeds. The weather now favors the clover and it takes over the field again.
I'm now beginning to look at clover fields as wildlife openings with native weeds forbs and clover. Eventually I'll rotate the field thorugh buckwheat and back to clover.
Thanks,
Jack