Soil, calcium deposition

Vinegar is recommended for cleaning a variety of appliances and other items that may be stained by hard water deposits. Automatic coffee makers, steam irons, dishwashers, teapots, faucet heads, and shower heads — over time, all accumulate calcium deposits from hard water. Groundwater, that is, water that travels through soil and rocks, accumulates dissolved calcium ions as a consequence of the natural weathering of minerals that contain calcium such as limestone and calcite, shells, and coral. At the same time, carbon dioxide in the air dissolves in water to form carbonate ions that combine with calcium ions to form a white solid, calcium... 

Lying between the broad belt of the eastern podzols and the westeni chernozem soils are the prairie soils, often designated as the Corn Belt soils. As would be expected, there are all gradations between the two groups on either side. Most of these prairie soils received enough rainfall for considerable leaching to occur and for the removal of the calcium into the drainage waters. Calcium deposits in the lower horizons are seldom... 

Iron oxide may also increase the beneficial effects of organic matter (Chesters et al., 1957). McIntyre (1956) concluded from studies of soils in South Australia that the chief influence on the structure of these soils is iron acting through the medium of an iron-organic matter complex. In semi-arid soils calcium and magnesium carbonates may also act as cements. These materials are carried in the soil percolate and a portion is deposited on aggregates, or may form hardpans at lower levels. 

Consider a lake with a smaU watershed in a forest ecosystem. The forest and vegetation can be considered as an acid concentrator. SO2, NO2, and acid aerosol are deposited on vegetation surfaces during dry periods and rainfalls they are washed to the soil floor by low-pH rainwater. Much of the acidity is neutralized by dissolving and mobilizing minerals in the soil. Aluminum, calcium, magnesium, sodium, and potassium are leached from the soil into surface waters. The ability of soils to tolerate acidic deposition is very dependent on the alkalinity of the soil. The soil structure in the... 

The most evident damage from acid depositions is to freshwater lake and stream ecosystems. Acid depositions can lower the pH of the water, with potentially serious consequences for fish, other animal, and plant life. Lakes in areas with soils containing only small amounts of calcium or magnesium carbonates that could help neutralize acidified rain are especially at risk. Few fish species can survive the sudden shifts in pH (and the effects of soluble... 

In a second experiment, we attempted to determine which nutrient elements gave the same quantitative response as the complete mineral nutrient solution. Results of this experiment demonstrated that nitrogen (NO3), phosphorus, and calcium, the elements applied in the field study, were the ones needed to produce a growth response quantitatively the same as the complete mineral nutrient solution. The need for repetitive application of these elements suggests that one or more may have a dual role, first as a nutrient and second as a soil conditioner that might exchange or complex with an Inhibitory molecule deposited in the soil by the herbaceous weeds. 

Iodine is widely distributed in nature, found in rocks, soils and underground brines. An important mineral is lautarite, which is anhydrous calcium iodate found in nitrate deposits in Chde. The element also occurs in brown seaweeds, in seawater, and in many natural gas wells. Its concentration in the earth s crust is an estimated 0.5 mg/kg and in seawater 0.06 mg/L. 

It is an interesting fact that the two elements most necessary in the maintenance of soil fertility are the related elements nitrogen and phosphorus, which occupy adjacent positions in Group V of the periodic table. Phosphorus occurs in nature only in the combined form, chiefly as the mineral phosphorite [Ca3P04)2]. Impure calcium phosphate, known as phosphate rock, is mined extensively in Tennessee, Florida, Montana, and Idaho. Large deposits of this mineral are also found in Morocco and Tunisia in North Africa. 

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