Comparative analyses of variable and fixed rate irrigation and nitrogen management for maize in different soil types: Part I. Impact on soil-water dynamics and crop evapotranspiration

Understanding the soil-water dynamics and maize evapotranspiration (ETc) under variable rate irrigation (VRI) fertigation (VRF) management with respect to soil spatial variability constitutes basis for developing effective water nitrogen strategies. This long-term research was designed quantify compare dynamics, including available (AW), ETc during vegetative reproductive growth periods of VRI, fixed (FRI) no-irrigation (NI) (FRF), VRF pre-plant (PP) in three different types [Crete silt loam (S1); Hastings silty clay (S2) (S3)] topography same field environmental conditions. The conducted Irmak Research Laboratory south central Nebraska, U.S.A., 2015, 2016 2017 (Zea mays L.) growing seasons a variable-rate linear move sprinkler system. No effect fertilizer on AW observed period. Overall, greater S3 as compared S1 S2 due lower elevation. Maize period significantly (P < 0.05) impacted by type all years treatment two years. 27 19 mm than S3, respectively, pooled data. During period, both were treatments, but differently Average FRI VRI 175 178 mm; 294 241 258 206 mm, respectively. Averaged across years, VRI; however, no significant difference > between any type. Similarly, 2017, S1. averaged PP had FRF. results indicate that primarily affected type, weather conditions (evaporative demand wetting) application timing. findings this showed is strong function not only practices (irrigation treatments), also physical properties, which need be taken into account VRF, FRF or types. quantified impact these can used guidance.