Infiltration and permeability describe the manner by which water moves into and through soil. Water held in a soil is described by the term water content. Water content can be quantified on both a gravimetric (g water/g soil) and volumetric (ml water/ml soil) basis. The volumetric expression of water content is used most often. Since 1 gram of water is equal to 1 milliliter of water, we can easily determine the weight of water and immediately know its volume. The following discussion will consider water content on a volumetric basis.
Available water is held in soil pores by forces that depend on the size of the pore and the surface tension of water. The closer together soil particles or aggregates are, the smaller the pores and the stronger the force holding water in the soil. Because the water in large pores is held with little force, it drains most readily. Likewise, plants absorb soil water from the larger pores first because it takes less energy to pull water from large pores than from small pores.
Saturation is the soil water content when all pores are filled with water. The water content in the soil at saturation is equal to the percent. porosity. The volume of soil voids that can be filled by water and/or air; inversely related to bulk density. Porosity is also known as "pore space.".
The relationship between these different physical states of water in soil can be easily illustrated using a sponge. A sponge is just like the soil because it has solid and pore space. Obtain a sponge about 6 x 3 x 1/2 inch in size. Place it under water in a dishpan, and allow it to soak up as much water as possible.
It also serves as the storage compartment for water. Infiltration. Water movement in the soil. Pore space in soil is the conduit that allows water to infiltrate and percolate (downward movement of water through the soil).
Plant available water or available water capacity is that portion of the water holding capacity that can be absorbed by the plant, and is the amount of water held between field capacity and wilting point. The volumetric water content measured is the total amount of water held in a given soil volume at a given time.
Most soil organic matter comes from previously living organisms. Temperature and moisture are the two main factors affecting its development. , especially crop residue and decaying roots, promotes aggregation so that larger soil pores develop, allowing water to infiltrate more readily. Permeability also varies with.
Experts now explain how soil texture, soil structure, and gravity influence water movement. In the basic water cycle, water falls on the land in some type of precipitation (rain or snow). It either is soaked into the ground or runs off into a body of water -- storm water or natural. Eventually, it returns to the atmosphere.
In the basic water cycle, water falls on the land in some type of precipitation (rain or snow). It either is soaked into the ground or runs off into a body of water – storm water or natural. Eventually, it returns to the atmosphere.
According to James Hartsig, a soil scientist with Duraroot Environmental Consulting, soil particles are either sand, silt, or clay. The relative amount of sand, silt, and clay in a given area makes up the soil texture. And, different textures of soil will have different size pores between particles. "These pores exist in gaps where soils particles ...
And, different textures of soil will have different size pores between particles. "These pores exist in gaps where soils particles come together. The large pores of a sand-dominated soil, where the particles are larger might allow more water flow than the micropore space in a clay-dominated soil, where particles are smaller and held together tightly."