Friday, October 19, 2012

Sampling Wetland Pore Water

Water added to the soil by rainfall or irrigation percolates downward to groundwater unless it runs off to surface waters, evaporates, is taken up by plants, or remains within the soil profile Chemicals such as fertilizers or pesticides can move with the water if they are not first broken down into other chemicals, transformed into gases, retained by chemical interaction with the soil solids, or taken up by plants or soil organisms. Successful crop production depends on careful management of soils, water, and chemicals so that plant needs are met as they occur in the growing season. Meeting these needs efficiently may also help to protect the quality of underlying groundwater by reducing the amount of chemicals being carried downward by recharge waters.Water in the soil originates from precipitation, irrigation, or upward flow from groundwater in areas with shallow water. It can contain dissolved minerals derived from the soil or atmosphere, as well as soluble pesticides, fertilizers, and other chemical compounds used or disposed of at the land surface. When soils are not saturated with water, then the pores also contain a mixture of gases, including nitrogen, oxygen, and carbon dioxide (as in normal air) and more exotic types such as methane, phosphate and hydrogen sulfide. Soil gases are produced and assimilated by soil organisms, plant roots, and decay processes, and they are exchanged with gases from the atmosphere. Without adequate exchange of gases in soil pores, crop growth cannot occur because the oxygen needed by the plant roots would rapidly become depleted. Most water management in soil is aimed at providing sufficient water for plants without producing conditions of excess water that prevent proper gas exchange.

The link above is the link for the video of sampling the nitrate in the water from the pores in the wetland in Springfield, Ohio. The links below support that.

Zach Smith

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