Plants cannot get enough water to stay healthy then

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plants cannot get enough water to stay healthy, then the soil is said to be at the wilting point . Whether you are a farmer, a gardener or just have a potted plant in your room, you want to monitor the soil moisture and add water before the soil gets to the wilting point. 18.3 Groundwater As gravity water flows down, it will reach a point where all of the pore spaces are filled with water. Then it is called groundwater . The amount of groundwater held in an area is determined by the porosity and permeability of the material where the water is found, usually sediments or rock. If subsurface material has high porosity and permeability and therefore can hold plenty of groundwater, it is called an aquifer . If subsurface material has low permeability, so that water cannot flow through it easily, then it is called an aquiclude . The upper limit of groundwater is called the water table . Above the water table the pores have both air and water, while below the water table the pores have only water–it is saturated with water. Capillary water Gravity water Soil Particle
GEOG 1401 Physical Geography 18—138 Ó Jeffrey A. Lee Figure 18-4. Groundwater terms. In some cases, aquifers are found under aquicludes and under the right circumstances, the water will flow freely from a well because the water is under pressure–the well top is lower than the water table. Figure 18-5. Artesian well. In nature, water tables may fluctuate both seasonally and over longer time periods. but when people pump groundwater, water tables may change considerably. When a well is dug and water is pumped out, a cone of depression often results. This is because pumping is faster than the aquifer's ability to recharge the area near the well; this recharge is based on the permeability of the aquifer. Unsaturated Zone/Zone of Aeration (water and air in pore spaces) Groundwater/Zone of Saturation (only water in pore spaces) Aquiclude Ground Surface Water Table Rain (Side view) Aquifer Artesian well Height of Water Table Aquiclude Aquiclude Aquifer
GEOG 1401 Physical Geography 18—139 Ó Jeffrey A. Lee Figure 18-6. Cone of Depression. A cone of depression can lower the water table under neighboring wells, which can leave shallower wells dry. Lowering the water table is significant because the deeper a well is, the more expensive it is to drill and to operate because you need more energy to lift the water a greater distance to get it to the surface. Groundwater is a good example of a natural resource. We look at resources in terms of being renewable or non-renewable. We can use water from the Mississippi River and the next day there will be more water to be taken. That is a renewable resource . Solar energy is also renewable. Copper is an example of a non-renewable resource , because once you remove the copper from an area, there is no new copper that takes its place. Oil, too, is non-renewable. Groundwater can be renewable or non-renewable. If enough rainfall percolates down to replenish what is used, it is a renewable resource. If we use it faster than it is replaced, then it is non-renewable.

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