Nitrogen budget and environmental losses from irrigated corn in the Suwannee River Basin, North Florida

Nitrogen (N) fertilizer is pivotal for augmenting the yield of key crops like corn (Zea mays L.); nevertheless, its excessive use risks nitrate-N (NO₃-N) leaching, potentially polluting water bodies and posing environmental and health hazards. Implementing best management practices, such as splitting fertilizer-N and utilizing soil moisture sensor-based irrigation, can mitigate NO₃-N losses. This study, conducted through two small-plot trials at the North Florida Research and Education Center, Live Oak, Florida, assessed the impact of increasing N rates (from 0 to 392 kg ha^-1 in 78.5 kg ha^-1 increments) on the N budget and environmental losses in irrigated corn hybrid 'Pioneer 1870'. The analysis highlighted fertilizer-N and corn N uptake as the principal N inputs and outputs, respectively, with negligible gaseous emissions (8.7 % of total N inputs) observed. N leaching emerged as the dominant environmental loss channel, with losses ranging from 53.8 to 105.4 kg ha^-1. Adoption of best management strategies, including split urea applications and sensor-based irrigation, was shown to curtail further environmental N losses, and the early season of 2023 witnessed minimal N leaching loads (0-4.7 kg ha^-1), which was attributed to low precipitation and efficient crop N uptake. The findings underscore the need for further research on various facets of global fertilizer usage in corn cultivation, encompassing rates, sources, timing, soil types, and water management, to holistically evaluate the environmental repercussions of agricultural intensification.