CanxiCalcium is taken up by plants as the cation, Ca2+. Calcium functions in the plant in cell wall development and formation. Calcium is not translocated in plants and consequently, the deficiency of calcium will be observed first in the new, developing plant tissue. Calcium deficient tissue fails to develop normal morphological features and will appear to be an undifferentiated gelatinous mass in the region of new leaf development.The calcium ion is referred to as a basic ion because the element reacts with water to form the strong base calcium hydroxide, Ca(OH). Calcium is held tightly on the negatively charged clay and organic particles in soils and is abundant in soils that have developed in arid and semi-arid climates. Because of this, it is primarily responsible for maintaining these soils at or near a neutral pH. In addition to unweathered primary and secondary minerals, soils often contain calcium in the form of impure lime (calcium carbonate, CaCO3) and gypsum (calcium sulfate, CaSO4). Except in the production of peanuts on sandy, acid soils, calcium deficiency in Oklahoma crops has not been substantiated by research. However, because calcium absorption by the developing peanut pod is not very effective from soils with a marginal supply of calcium, peanut producers often apply gypsum over the pegging zone just before the plant begins to peg to assure the crop will be adequately supplied with calcium. For most soils, before the available calcium level reaches a critically low point, the soil pH will become so low that soil acidity will be a major limitation to crop production. Since the common correction of acid soils is to add lime in amounts of tons per acre, this practice will incidentally maintain a high level of available calcium for crops.
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