In nature, diatoms frequently grow under nutrients limiting conditions and although nitrogen and iron have been reported as
limiting nutrients; there is also evidence of phosphorus limitation (Girault et al., 2013).
In this study, one can speculate that boron is a possible candidate to main
limiting nutrient for these Cerrado native grasses, since it was the only nutrient that had its concentration increased in area 2 due to dung addition.
TN:TP ratio,
limiting nutrient and trophic state indexes
First, we consider input
limiting nutrient continuously.
Whatever runs out first--that's called a "
limiting nutrient."
N:P ratios ranged from 130:1 in Copacabana Bay, 124:1 in Cohana Bay, 110:1 in Tiquina, to 79:1 in Alaya, showing clearly that phosphorus is the
limiting nutrient in all cases.
In crop production, Liebig's law of minimum (Y = kX up to a plateau) and Mitscherlich's law of diminishing returns (Y = A[1 - [e.sup.kX]]) are well known response models to X, the growth
limiting nutrient, where Y is crop yield, A is maximum yield, and k is a proportionality constant (Trionfo, 2000).
When land applying manures and composts you also should calculate the phosphorus requirements of the crop, and land application rates should be calculated based upon the most
limiting nutrient. By applying based on the
limiting nutrient, we minimize the potential for over applying either nitrogen or phosphorus, both of which can cause over fertilization of lakes and bays leading to algae blooms.
The objective of this study, therefore, was to identify the most
limiting nutrient to production of the crop as the strategic entry point to effective management and subsequent formulation of rationalized packages.
In most aquatic systems it is found to be either phosphorous or nitrogen that is the
limiting nutrient. However, where the combination of nitrogen and phosphorous supply to waterways is very high, as in rich agricultural areas, the receiving rivers, lakes, and estuaries exhibit extreme eutrophication.
However, analyses of total nitrogen (TN) and total phosphorus (TP), the key parameters to determine the trophic status and the
limiting nutrient that controls algal growth, were not included.
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