I have that book and I think it is a very good one. What puzzles me regarding velvetleaf is the varied situations where it becomes a problem.
Few examples that I have experinced recently (organic):
10 acres silty-loam soil, last year of convetional farming was 2020
2020 vine rootstocks (I am not sure about the correct term, rootstocks grafted?), a lot of chemicals and soil compaction in the fall
Febraruary 2021 cover crop of cereal rye + common vetch
June 2021 soybean on minimum till. A good stand of soybean and an excellent stand of velvetleaf, many days of handwork to get rid of it (after seed setting for many plants)
March 2022 mimimum till after sprying some biologicals
May 2022 Sunflower with no fertilizers, very very low population of velvetleaf. Why? Because sunflower and velvetleaf had similar root systems, so the soil does not need velvetleaf to improve overall fertility? Maybe in part yes, but in other sunflower fields velvetleaf did not suffer too much. Because of the biologicals? I left an unsprayed spot, and there was no more velvetleaf than treated areas. Because of rye the year before? Maybe, but not so convinced. Because of the velvetleaf that has fixed in one year the soil fertility problem, maybe extracting some nutrients and making then available?
I am very interested in cover crop – crop combinations that may have had an effect on controlling velvetleaf. And to come back to the post title, does velvetleaf prosper best at low soil Eh values? I realize that the question cannot be easily answered, but what I like to think is that its seeds germinate at low Eh values (Charles Walters, ethane forming conditions), and maybe the right cover crop can change that value to a non forming ethane one.
The observation on liquide manure and velveltleaf maybe is pointing to the same Eh problem.