## 2.22.6. Leaching Losses of Nitrogen[¶](#leaching-losses-of-nitrogen "Permalink to this headline")
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Soil mineral nitrogen remaining after plant uptake, immobilization, and denitrification is subject to loss as a dissolved component of hydrologic outflow from the soil column (leaching). This leaching loss (\\({NF}\_{leached}\\), gN m\-2 s\-1) depends on the concentration of dissolved mineral (inorganic) nitrogen in soil water solution (_DIN_, gN kgH2O), and the rate of hydrologic discharge from the soil column to streamflow (\\({Q}\_{dis}\\), kgH2O m\-2 s\-1, section [2.7.5](https://escomp.github.io/ctsm-docs/versions/master/html/tech_note/Hydrology/CLM50_Tech_Note_Hydrology.html#lateral-sub-surface-runoff)), as

(2.22.8)[¶](#equation-22-17 "Permalink to this equation")\\\[NF\_{leached} =DIN\\cdot Q\_{dis} .\\\]

_DIN_ is calculated assuming that a constant fraction (_sf_, proportion) of the remaining soil mineral N pool is in soluble form, and that this entire fraction is dissolved in the total soil water. For the Century- based formulation in CLM5.0, the leaching acts only on the NO3\- pool (which is assumed to be 100% soluble), while the NH4+ pool is assumed to be 100% adsorbed onto mineral surfaces and unaffected by leaching. _DIN_ is then given as

(2.22.9)[¶](#equation-22-18 "Permalink to this equation")\\\[DIN=\\frac{NS\_{sminn} sf}{WS\_{tot\\\_ soil} }\\\]

where \\({WS}\_{tot\\\_soil}\\) (kgH2O m\-2) is the total mass of soil water content integrated over the column. The total mineral nitrogen leaching flux is limited on each time step to not exceed the soluble fraction of \\({NS}\_{sminn}\\)

(2.22.10)[¶](#equation-22-19 "Permalink to this equation")\\\[NF\_{leached} =\\min \\left(NF\_{leached} ,\\frac{NS\_{sminn} sf}{\\Delta t} \\right).\\\]

