Analysis of anthropogenic nitrogen loads and their impacts on nitrogen surplus and groundwater contamination in Palestinian agricultural systems

ABSTRACT This study assesses anthropogenic nitrogen flows from agricultural activities in Northern Gaza, focusing on citrus and olive orchards, and evaluates their environmental implications. The methodology combined field measurements, farmer surveys, and simulations with the FAO CROPWAT 8.0 model to estimate crop water needs and nitrogen inputs from fertilizers, irrigation, rainfall, and atmospheric fixation. Outputs were calculated from crop uptake, leaching, gaseous losses, and runoff using established coefficients. Findings indicate a substantial nitrogen surplus, reflecting inefficient nutrient use and heightened risks of groundwater pollution through nitrate leaching. Sensitivity analysis confirmed that adjusting manure applications and improving irrigation water quality could markedly reduce surplus levels. The results underscore the urgent need for more efficient nutrient management strategies to minimize environmental degradation while supporting agricultural productivity. The study highlights the importance of integrating nutrient and water management in semi-arid farming systems, particularly in fragile regions such as Gaza where water scarcity and environmental vulnerability intensify the challenge. These insights provide a foundation for policies and practices that can enhance fertilizer efficiency, protect water resources, and advance sustainability in the agricultural sector.