Modeling stream water nutrient concentrations and loadings in response to weather condition and forest harvesting

According to the assessments of the model simulations and the field measurements, the increased watershed soil nutrient losses through the stream exports after forest harvesting may not cause the decline of the watershed soil productivity because (1) the annual increments of the stream nutrient exports were small, with 2.34 kg ha−1 year−1 for NO3−-N, 0.93 for NH4+-N, 3.34 for Ca2+, 0.30 for Mg2+, and 5.21 for K+ and (2) the increased watershed soil nutrient losses occurred during the stage of forest regeneration when vegetation growth requires low soil nutrient supply.