That's a lot of questions. Let's see what I can help you with. Seed comnepias are always searching for varieties that do better in particular conditions. There are so many variables to consider. Some plants do better on certain soil types. Some are more resistant to specific diseases than others. It's all about putting the right seed on the right piece of ground. Test plots are very common tools used to determined which hybrids do best in a particular situation. I'm not a sweet corn grower, but I'm sure you can buy heritage or heirloom seeds.There are many ways we can protect soil. Changes in tillage practices have gone a long way towards keeping soil in place. This is partly why we aren't experiencing another Dust Bowl with the current drought like we did in the 1930s. We aren't doing nearly as much clean till as we used to. By clean I mean working the ground until all the previous crop residue is buried. Many farmers are doing minimum or reduced tillage now. This leaves some residue on the soil surface which helps water infiltrate the soil instead of running over the top during a heavy rain. No till is popular especially as you head into the plains states, but it is gaining in popularity in the Midwest where I farm. We do some no till, and I would like to do much more even to the point of not doing any tillage on our entire farm. This year we are trying for the first time. A cover crop grows after harvest until the first hard freeze or until you kill it off prior to planting. Different covers have different uses. The main goals are to build soil organic matter (which improves nearly every soil attribute), reduce erosion, improve soil structure, and capture nutrients.I think most of the soil you buy at retail stores in good topsoil. I can't say what's been done to it other than being bagged. It will come with some weed seed in it. I used to work at a store and we sold thousands of bags of top soil each year. I had my employees go outside and pull weeds growing through the bags on a regular basis. You can buy soil test kits for fertility and pH levels and should be able to find them at the store that sold the soil. If there is a particular safety concern you could either call the vendor or find a lab that tests soil.Each year before we plant we want to be sure the soil temperature is high enough for germination. Above 50F. You don't want to have seed sitting in cold soil, especially moist soil, if it's cold because it could spoil in the ground.I have to ask a friend of mine about apples. Most of the year I work 8-5, but during planting and harvest I might work 10-15 hour days. I don't mind that at all because I love being in the field. All I can say about bookwork is that it's necessary!