L/D -Bell vs Eliptical spanload?
1)So if we have plane with 3000kg and we must have best L/D and if wingspan is not constrain,then we must choose bell span-load so our new wing will be 22% longer and it will have 11% smaller induced drag?


All other parameters except span held constant this is true. 


  2)Why Al Bowers talk like weight and wing bending moment are same thing?If some plane have bigger wing bending moment,that dont neccesery mean that it has larger weight than plane with lower wing bending moment...


Wing root bending moment corelates to the load factor N * weight. Also spar cap sizing is done with REF to the the root bending moment which in turn drive the wing weight. 


  3)Why all gliders use elliptical span-load if bell span-load has better L/D?


To be precise, all gliders do not use elliptical span-load. However, it's not wrong to say all gliders tend to use span-load distributions which are very close to elliptical loading. What elliptical span-load gives is the lease induced drag per given span. Say you start with an airplane with a given span and increase the span by 22%. Yes, you will get 11% decrease in induced drag but if you use elliptical loading on that increased span, your induced drag will be even smaller. (32% decrease)


  4)What do you think,when will aircraft industry switch to the bell span-load solution(if ever)?


I am not qualified and/or knowledgeable to answer this. 
Just for the info, there are many more viable and attractive solutions available with lower risks involved, such as the ones investigated in the NASA N+3 program.