Contrasting corn yield responses to nitrogen fertilization in southeast coastal plain soils

Nitrogen (N) fertilizer recommendations based on yield goals are common and do not consider variability in soil N supply between fields. transformations soils dynamic may vary widely among different soils, climates, cropping systems, management practices, making it difficult to provide general recommendation rates for a region, state, or even county. To optimize fertilization corn ( Zea mays L.), eight field trials were conducted fields at the Edisto Research Education Center of Clemson University 2018–2021. The varied pH, inorganic N, practices (irrigate, dryland, cover, no-cover crop), climatic conditions (temperature precipitation). Six nitrogen rate treatments used during 2018 2019, 2020, five 2021 trials. Test sites each year except which same site but differentiated by multi-species crop treatments. was applied as complete one-time dose all several splits 2019 2020. yields generally increased with rates; however, strong variation up 4–11 Mg ha ?1 existed level Based responses, divided into two groups: low-yielding high-yielding sites. average produced 3.8 corn, 137% less than harvested from (9.0 ). agronomic use efficiency (AgNUE) almost double (32.68 kg N) compared (17.16 N), differences wider partial factor productivity (PFP economic optimum (EONR) remained below 300 no marked difference However, relative (ratio unfertilized control giving highest yield) comparatively lower (29.45%). Baseline precipitation identified major factors controlling responses fertilization. variations driven make challenging, indicating need site-specific southeast United States.