Content Variation and Potential Runoff Loss Risk of Nutrients in Surface Water of Saline-Alkali Paddy in Response to the Application of Different Nitrogen Fertilizer Types

As the saline-alkali paddy area continues to grow, nutrient (e.g., nitrogen (N) and phosphorus (P)) runoff loss is becoming more serious in world. The N-fertilizer application affects risk paddy. Selecting suitable fertilizer types reduce beneficial agricultural sustainability. However, effects of are not clear. This study measured N P concentration surface water paddy, using various N—fertilizer treatments (i.e., urea (U), with urease—nitrification inhibitors (UI), organic–inorganic compound (OCF), carbon—based slow—release (CSF), no fertilization (CK)). Based on structural equation model, both phosphate (PO43−-P) total−P (TP) concentrations had a positive influence total-N (TN) regardless N−fertilizer applied. Potential risks ammonia—N (NH4+—N) nitrate—N (NO3−—N) losses were reduced UI treatment, but TN TP increased. At panicle-initiation stage, NO3−−N, TN, CSF OCF lower than U. can control during rice-growing season. should be suggested for