عنوان مقاله [English]
Complexity, variety and improper management of agricultural contaminants and high volume of water losses due to improper design and management of irrigation and drainage systems increase share of agriculture in water resources, soil and environment contamination. Control and reduce pollution of the available nitrogen in the fertilizer is needed to understand the biological cycle in the ecosystem. The aim of this study was to simulate nitrogen cycle and evaluate the impact of soil moisture content on denitrificaton rate under furrow fertigation systems using HYDRUS model. In this regard, field experiments done under constant furrow fertigation in the furrow with 83 meters in length and clay-loam soil texture. The conversion coefficients of nitrogen cycle included dispersion coefficient and order conversions from the parameters of nitrogen cycle based on observational data, soil moisture and nitrate concentrations using inverse modeling techniques that were obtained. To study plant effect on the nitrogen cycle, the model is studied in presence and absence of plant. Statistical indexes such as RMSE and R2; model was used to evaluate the simulation results. The results showed that modified Van Genuchten method performance with statistical indexes RMSE=0.02879 and R2=0.9899, considering presence of plants better estimate of parameter values of nitrogen cycle concentrations in corn furrow irrigation. The maximum soil moisture where denitrificaton occurred, 50% of the saturation value is obtained and compared with the premise Williams (1995), using denitrificaton factor in the simulation of the nitrogen cycle in corn fertigation was led to improved results.