@Setanta,
One theory in the "evolutionary development of ag" was one of "Protection of plant resources within a fixed migration zone". This one seems reasonable because we know that, as a population of hunter gatherers increased, they either had to range farther and wider or elseget a sense of "Seasons" and the natural bounty presented in those areas. So migration patterns of paleoliths included the "protection" of fruit groves and sources of fruits.
It is clearly evidenced that fruits were the first ag product based upon "coprolite" (doo doo) depsits in shelters and caves where humans lived.
Seeds and grains and beans came much later since the normal carp coating of a seed is a toxic family of chemicals called
LECTINS. Lectins make grains and beans unpalatable because they induce gastric distresses and vomiting. It was only when our ancestors dicovered that, when the grains were smashed and the beans cooked into submission would grains and beans become improtant crops. Stuff like
einkorn and emmer and wild lentils were exploited as some of the first grain products based upon their growth areas.
PEriglacial areas especially areas around terminal moraines and side moraines were made of fairly shitty soils. In fact, these areas we still call "Barrens" where the soils are rich n packed clays or leached alkalis, also the sandy barrens of the areas behind morines are some of the baddest soils for farming. SO actually the coming together of several features were needed to folks to dip a tentative toe into population sustaining ag. SOme of these needs were:
1larger growing population to make it necessary
2 a culture of "protecting fruit trees and berries" (concept of not dumping into the groves)
3 A climate not too doused with rain so that shrubs and margin forests and grasslands abound (sorta like savannahs)
4 wild populations of specific resource plants that could be exploited
5 a concept of smashing and cooking wild grains had to be developed
6 a concept of "Storage" of bounty
7. cooking smashed grains over a Fire and storage as agricultural concepts were probably local cultural features related to people changing from hunter gatherer to ag
Edaphic (environmental ) factors conducive to growth of exploitable plant materials is a need. They actually been revisiting the "lake dweller" theory as part of the neolithic revolution or the "hillside settlements" as starting areas for ag.
-------------------------------------------------------------------------------
A really good example of ag development can be seen right here in PA.
About 12000 to(even 20000K BP Dr Atavasio of Pitt feels that hes got evidence for 20000 year old settlements in PA) about 6000K, we had Paleo Indian tribes that milled around the periglacial areas of PA(In pA, the latest glacial advances only came as far south as Allentown). The rest of the land to the BAys were typical periglacial tundras and peat swamps with lotsa game.
AS the PAleo period began winding down into the "transitional phase", we could see the evidence of settlements in the higher ridge areas and in the more dried out areas like the limestone valleys that sweep through central PA. These areas were rich in NUTS. In Pa, the first attempts at ag were the exploitation of NUTS. The Indians then used techniques to strip bark and "girdle trees" to create plots where they could grow stuff like pumpkin (wild gourds and melons were a common wild plant), beans (ya gotme where they got beans ,Ill have to do some further research into Paleoindian cultivation of beans). A series of grain crops called Maranth and millet were common grains , easy to grow in this area. Evidence abounds from the proto Susquehannock camps along the tribs of the SUsquehanna and Ohio, that Cooking Pots, made of clay were a cultural feature that was either exchanged, traded, or self developed (I believe in the exchange of cultural features because weve seen projectile tips change remarkeably fast all over the countryside)
As the population transitioned into the "old woodland culture" Ag was clearly firmly established. Archeologists have found exampes of storage areas and bins in long house structures .Also, several of the Pallisaded "Indian Forts" of the 1000BC time pwriod were demonstrating ag practices that were quite advanced.