Experimental and Numerical Investigation of Nitrate Movement through the Soil in Sugarcane Farms

Sugarcane, a strategic and important crop having long duration of growth, has been classified as plant which requires high amounts of water and nitrogen fertilizer. However, nitrogen (N) also forms some of the most mobile compounds in the soil-plant-water system. There has been mounting concern about role of agriculture in nitrogen movement, in the form of nitrate, into the groundwater, as it represents the most used mineral fertilizer which is applied to the agricultural land. In this study the aim is to simulate nitrate leachate in furrow irrigation of sugarcane farmlands by employing HYDRUS-1D model. To this aim, nitrate concentrations of water samples, which are collected from drainage systems from time to time, are to be measured. Nitrate movement, during the period of sugarcane growth, is simulated using both linear and nonlinear modeling methods by application of equilibrium and non-equilibrium equations. Hydraulic parameters of soil are to be evaluated by using commercially available program Rosetta. The HYDRUS-1D model shows high sensitivity to the moisture parameter of Van-Genuchten equation (n), saturated hydraulic conductivity (Ks),and saturated moisture content (θs). Results demonstrated the validity of the model for simulating nitrate movement in sugarcane field, but concentration of nitratewas underestimated. Generally, application of linear method combined with equilibrium equation showed the highest accuracy with high correlation coefficient (94%) in simulation.

کلیدواژه ها:

Nitrate leaching ، sugarcane ، direct and inverse modeling ، HYDRUS-1D