I watched the Victory Garden today and some of the old ways are now reversed when it comes to planting. Trees in particular and their soil. Most of us now know not to lop branches flush with the trunk and paint them (as was the old way) and now the concensus is to plant the trees in non-amended soil. I mentioned this to Dave some time back, how the National Arboretum's advice was to plant trees in ordinarly un-amended garden soil while they are quite young. It seems they are far hardier and less prone to disease. Also the Victory Garden guy (sorry can't remember his name) said it used to be that we were told not to fertilize trees in the fall because it would produce new growth which might be killed back by frost. It appears that this too has changed and we are to feed the trees in the Fall with a slow release fertilizer which will continue till the Spring. I can't say I'm happy about the last piece of advice.
The advice your got from the program has been in general use by professionals for some years now. New advances in soil and plant management happen often, but it take years to get the information out to most gardeners. Lots of books just get cosmetic changes and get reprinted. Articles in magazines often just regurgitate old stuff.
Most plants do well enough in average garden soil and do not need specially amended soil. Very sandy soil and very clay soil might need improvement, but it is better to amend the area rather than just the hole.
Research on how woody perennials grow has shown that substantial root extension happens in the fall while in the spring shoot/stem extension dominates. So fall fertilizing with slow release material mimics natural processes of leaf fall, slow break down, and more rapid decomposition from spring into summer.
Many time release fertilizers are temperature-sensitive. Depending on the prill coating, nutrients start releasing in the presence of moisture when the soil temperature reaches, for example, 65F or 72F. There are special coatings for colder regions where nutrient release starts at lower temps.
Organic materials start to decompose at about 40F but really takes off when the temperature reaches the mid to upper 60sF.
Thanks so much Marsh - you are such a blessing and minefield of knowledge. I'm glad you posted because I was going to post a question for you this morning. I have never worked with clay soil before as you know and have amended the beds at the front of the house and done it very well - i.e. took out about 12inches of clay and replaced it with good soil and compost etc. However upon reading an old book of mine on drainage and in particular about roses the advice was to lay drains in the subsoil after it had been broken up. Now we are too long in the tooth for that kind of exercise but a thought came to me. Why don't I plant my roses in the septic drainfield!! Does this make sense or not?
The root grow whenever the temperature and soil conditions are warm enough but put on a burst after stem extension and before the ground fully freezes up. Different kinds of trees have different timing but generally the deciduous fruit trees and subtropical evergreen fruit trees follow this pattern.
If you want to move a tree in the Spring, you root prune in the early fall to allow time for new side roots to develop so that the soil ball is stronger and the plant better able to withstand transplant.
When, oh so many years ago, I studied plant and soil ecology, we didn't spend much time on microbiology but did study forest litter ecology. In Wiscosin Maple-Beech forests, a minimum of three years of leaf fall was commonly present. In conifer forests a minimum of 5 years litter could be identified.
So, think in terms multiple-year, sustained yield system. Also remember that if a fruit orchard gets stressed from drought or poor nutrition, the following year's (sometimes two) productivity falls off.