3 adjectives to describe crumble

There in front 'tis rent asunder, And the cloudy bastion crumbles Underneath the deafening thunder; There I see the scarlet gleaming!

The soil of this plain is a brown clay, which in the dry weather crumbles into small pieces, so that the horses sink deeply into it; but in the wet season the whole is deep mud; it, however, appears to be very fertile, and produces an abundance of grass; the trees consist of bauhinia, acacia, and some eucalypti.

The deep ruts of the rainy season dry up and the once muddy earth crumbles into thick heavy dust, into which the feet of the wayfarers sink.

3 adjectives to describe  crumble