These conversions are analyzed based on nitrogen and phosphorous balances using a mass balance approach.
Research based on nitrogen and organic carbon balance has shown that the restoration of a soil-groundwater system is a complicated process that usually requires changes in the extent and intensity of agricultural activities and consistent attention to the effects produced by natural conditions.
Most plant food is based on nitrogen, essential for leafy growth, phosphorus for healthy roots and shoots, and potassium to promote flowering and fruiting.
Crude protein was calculated based on nitrogen content in the biomass.
The treatments did not have significant effects on nitrogen balance, however, nitrogen intake, retained or excreted in faeces was higher with lucerne than sorghum hay.
Thus, although the data on nitrogen balance was measured on different days, the estimated "nitrogen gap" showed a wider margin for cafeteria diet-fed rats than for controls.
Pennino et al. (2016) examined the transformations of nitrogen derived from a wastewater treatment facility, based on the nitrogen mass balance and the δ15N and oxygen stable isotope ratios (δ18O) in the tidal Potomac River estuary from Washington, D.C., to the Chesapeake Bay.
Nitrogen balance was calculated based on administered nitrogen from protein and amino acids minus nitrogen in urinary urea without including other potential losses via, for example, skin and stool.
Protein adsorption could then be calculated based on a mass balance for nitrogen, with a nitrogen factor (NF) of 8.40 for Spezyme CP cellulase, 8.28 for Multifect xylanase and 3.25 for Novozyme 188 β-glucosidase [ 23, 24].
Nitrogen efficiencies, calculated based on the nitrogen stocks, provide useful and insightful information beyond the conventional eco-efficiency measures defined from the nitrogen balances.
