jujus are tough indeed! Btw, i am not partial to nitrogen when growing fruit trees, and not just for jujubes. I would rather be using a higher ratio of p and k to n than the other way around. And this desert earth, it seems to be the default setting! We don't even fertilize our trees. Grass clippings, wood chips/mulch and kitchen refuse are all they've been getting.
it is yes and no, as we bagged shanxi's this summer and it produced fruit, but not as densely as open-pollinated branches, and the fruits were smaller but at least were of the same quality as the unbagged ones.
while it was a "true positive" finding of being self-fertile, i am afraid they might be sub-par when grown by their lonesome. Of course, you could always graft other varieties and/or let your rootstock flower if you're not satisfied with your future shanxi's performance.
forgot to add, there seems to be more than one cultivar being sold as 'shanxi li'. Ours is the globe type(not the slender type have seen from other posters) we obtained from Roger M.