Relation of soil texture to bulk density (BD) Soil class Sand BD gm/cc 1.6 Sandy loam Loam 1.5 1.4 Silt loam Clay loam Clay 1.3 1.2 1.1 In the figures above, sandy soil have greater BD than clayey soils. This means that in the dry condition, the sandy soil has less volume occupied by pore space. Why is it then that the rate of water movement in clay which has a lower BD is slower than sandy soils which has higher BD values?