Long-term variation (1960-2003) and causal factors of non-point-source nitrogen and phosphorus in the upper reach of the Yangtze River

► This study updated the historical dynamics of N and P in the Yangtze River. ► The spatial patterns of N and P were characterized at a large basin. ► The causal factors were quantified to study their periodical contributions. ► The development of policy was addressed to explore the causes of NPS pollution. ► An IECM-RUSLE model was proposed for simulating NPS in a large basin.