Since no one has responded, I'll give you my .2 cents worth.

It's going to be very difficult to compete with the soybeans and corn your farmer is planting. Not knowing if the rest of the surrounding area outside the fenced 100 acres is hardwoods or farmland as well, I'll assume its both like what you are hunting on.

Deer in general, more so with bucks, want a thick cover to bed in, so you need to scout and see if that is being provided. Just because you have the 30 acres of woods, does'nt mean its good cover. So I would look into finding the bedded area, or create a sanctuary so deer can go to and feel safe. This will help to keep the deer on your hunting parcel. Keep in mind that deer will bed in the corn field also, but depending when the farmer harvests the corn, that will soon be gone and the deer will disperse.

The deadliest ambush site on a farm is undoubtedly a funnel that channels deer from one wooded site to another. Deer are really attracted to edge habitat, ones that are soft or have a buffer zone such as a ring of saplings that seperate an abandoned field from a woodlot. Look for these.Deer will weave back and forth between these two types of habitat all season long.

The farmer has a great source of summer food, you may want to look into enhanceing native forage. Native forage enhancement can be defined as, "The art of manipulating native habitat to augment the nutitional quality for wild inhabitants", in this case, deer. One technique is to cut down some none valuable timber to allow sunlight to reach the forest ground floor and allow native grasses, brush forage to grow. If you do this in strips, this will attract deer to utilize as a trail and you can also plant various seed blends such as clover, chicory etc. in these stripes or just fertilize the strips, increasing both density and nutritional value of the herbaceous layer.

The creek is a good water source for the deer, walk it and look for trail crossings and areas that deer may gather for drinking.

Along with any clearing that you can do within the woods, you can create a "Honey Hole", "Harvest Plot" or "Hotspot" that you can hunt over during hunting season. Many of the commercial seed companies sell such seedblends that you can plat in the fall, around Aug. and have the crop ready to hunt. (depending on you hunting season) WTI has Secret Spot, Biologic has Hot Spot, Plotspike has Quick Stand, Evolved Habita's has Easy Plot and so on.

Don't forget to put down supplements in the spring and summer in the wooded area. This will also attract deer and possible with the right formula of thick cover, farmer crops, natural enhanced vegatation and your own 1/4 honey hole(s) food plots, may retain the deer in your area.

One last tid bit, it's very difficult to manage a deer herd with only 100 acres, I have 92. The best you can hope for is to attract them and offer them an sancutary to hide once the pressure of hunting season starts.

Good luck.