Asparagus Problems

[Plot22]

My Asparagus is now 5 years old and cropping  well. I have followed all the guidelines in previous years as regards cutting and each winter have heavily mulched with farmyard manure. My problem is some of the crop is woody compared to previous years and I have double the usual quantity of pencil thin ones than in previous years.
Any thoughts would be appreciated

[Plot22]

[goodlife]

Could you draw some surrounding soil on top of the crowns..it might be that the plants are  in too shallow soil,,,even with the mulching as manure will disappear almost next to nothing when it rot down.
Or if you can bring some soil over from elsewhere from the garden.

[ACE]

A grower  I  worked for as a yoof, knew when rushed through the watering because the crop got woody. Don't scrimp on the watering, it has been a bit dry this last few weeks.