Pregnancy Weight Gain: Facts. 1  For women who were a normal weight before pregnancy with a BMI of 18.5-24.9 the recommended weight gain guideline is 25-35 pounds. 2  Women who are underweight pre-pregnancy with a BMI of less than 18.5 should gain between 28-40 pounds unless your health care provider says differently.
Tilth generally refers to the physical condition of the soil as it relates to plant growth. Favorable tilth implies good conditions for seed germination and root proliferation, allowing crops to thrive.
Soil liquefaction describes a phenomenon whereby a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress, usually earthquake shaking or other sudden change in stress condition, causing it to behave like a liquid.his is because a loose soil has the tendency to compress when sheared, generating large excess porewater pressure as load is transferred from the soil skeleton to adjacent pore water during undrained loading. As pore water pressure rises a progressive loss of strength of the soil occurs as effective stress is reduced.