I guess my question is, if your TnMing twice a year, mowing dense, healthy vegetation each time, and not tilling, how do you avoid having a thatch layer? You’re completely at the mercy of the decomposition rate, no?
Exactly! That is what I want. With the right mix of C & N you are essentially composting and building OM from the top down. This supports the microbiom that improves nutrient cycling and reduces (or even eliminates) the need for fertilizer. A good balance is important for decomposition. That is why we mix or rotate legumes and grasses.
Unlike a farmer who is trying to maximize yield to maximize profit, objectives for deer managers are quite different. Food plots are a small part of a deer's overall diet. We are trying to select crops that provide good nutrition for deer during times when nature is stingy to even out the dips. In late spring when things are lush in my area, it doesn't matter if a deer is eating my food plots or native poke berry. In the middle of the summer when native foods dry up in my area or the dead of winter when only low quality browse is available, food plots can play an important role.
With a good mix of grasses, legumes, native forbs and weeds, decomposition will occur building OM. Let's start in the spring. I will soon be T&M a mix of buckwheat, sunn hemp, and then using a no till drill to drill sunflowers into that mix. That will cover our summer stress period. By fall, these warm season annuals will be dying naturally. I when then broadcast a cover crop mix of Turnips, Winter Rye, Crimson Clover the summer crops will still be standing. There will be plenty of bar soil under the canopy. I will then spray and mow the field. That just mowed will form a mulch for the seed just broadcast and have all fall, winter, and early spring to decompose. Next spring when I plant some of the fall crop, the previous years summer crop should be decomposed. The fall planted crop will need to be terminated.
What I do the follow spring depends on what happens over the winter. If we have a good mast crop and deer don't eat all the turnips, I'll probably use a tiller set high so it barely touches the top inch. Turnips don't terminate well with gly, but the tiller terminates them easily. This is not enough to disrupt the Crimson Clover or Winter Rye. They will continue to grow and provide food in early spring until I'm ready to plant again in may. WR and crimson will terminate easily. If we don't have a good mast crop I will not need to terminate turnips, the deer will have done that.
If for some reason you don't get the decomposition you want with your crops, you can do the same thing with a tiller. On the old QDMA forum this min-till technique was written about an a thread called "Thirt" - a mix of thatch and dirt. Microbes in the soil speed decomposition. It takes very little soil thrown on dead vegetation to speed decomposition.
Match your technique to your tools and situation.
Thanks,
Jack