SEATTLE — Gov. Jay Inslee has signed legislation making Washington the first state to approve composting as an alternative to burying or cremating human remains. The measure signed Tuesday allows licensed facilities to offer “natural organic reduction,” which turns a body, mixed with substances such as wood chips and straw, into about two wheelbarrows’ worth of soil in a span of several weeks. Loved ones are allowed to keep the soil to spread, just as they might spread the ashes of someone who has been cremated — or even use it to plant vegetables or a tree. …Supporters have said the method is an environmentally friendly alternative to cremation… and conventional burial… taking up land.