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A four-year study was conducted in western Kansas on a deep, well-drained, loessial Keith silt loam (Aridic Argiustoll; fine silty, mixed, mesic) to develop a Best Management Practice (BMP) for nitrogen (N) fertigation for corn using subsurface drip irrigation (SDI).

Residual ammonium- and nitrate-N levels in the soil profile, corn yields, apparent nitrogen uptake (ANU), and water use efficiency (WUE) were utilized as criteria for evaluating six different N fertigation rates, 0, 90, 135, 180, 225, and 275 kg/ha. A BMP was developed indicating an N fertigation level of 180 kg/ha with the total applied N including other N-sources of approximately 215 kg/ha. The BMP also states that irrigation is to be scheduled and limited to replace approximately 75% of crop evapotranspiration (ETc).

Corn yield, ANU, and WUE all plateaued at the same level of total applied N that corresponded to the 180-kg/ha N fertigation rate. Average yield for the 180-kg/ha N fertigation rate was 13.4 Mg/ha. Corn yield to ANU ratio for the 180-kg/ha N fertigation rate was high (53:1). Results emphasize that high-yielding corn production also can be efficient in nutrient and water use. The BMP can be used for managing SDI fertigation of corn on the deep silt loam soils of western Kansas.