Mean annual concentration of mineral nitrogen in soil water (mgN / kgH20) in the present day scenario

Definition: Mean annual dissolved concentration of mineral nitrogen in soil water (mg of nitrogen per kg of water), averaged for both soil layers. Interpretation: The dissolved N concentration is calculated as the ratio of the mineral N store to soil water store, which assumes that all the mineral N is in solution. Rainfall has a strong influence on the pattern of both these stores, but not on their ratio. The pattern of mineral N concentrations is explained by the effect of air dryness (saturation deficit) on the mineral N store (mainly controlled by NPP) which is greater than the effect of air dryness on the soil water store (mainly determined by rainfall or energy limitation). This gives a pattern of N concentration in soil water that decreases as the climate-average air dryness increases from temperate to semi- arid tropical environments. Notes: These are model-based estimates from the BiosEquil model. Results are given for the aBasea (pre-1788) and aAgrica (present day) conditions. The aAgrica case includes (1) current agricultural inputs of water from irrigation; (2) current agricultural inputs of nutrients (nitrogen and phosphorus) from fertiliser, legume crops, and legume pastures; (3) current nutrient offtakes by product removal (harvest, stock). NMnlConc0.Agric a Mean annual concentration of mineral nitrogen in soil water (mgN kgH2O-1) in the aAgrica (present day) scenario NMnlConc0.Base a Mean annual concentration of mineral nitrogen in soil water (mgN kgH2O-1) in the aBasea (pre-1788) scenario Data is in geographics and GDA94.

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