Effects of Different Irrigation Water Types, N Fertilizer Types, and Soil Moisture Contents on N2O Emissions and N Fertilizer Transformations in Soils

• Published in: Water, air, and soil pollution Vol. 227; no. 7; p. 1
• Main Authors: Shang, Fangze, Ren, Shumei, Yang, Peiling, Chi, Yanbing, Xue, Yandong
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.07.2016; Springer Nature B.V
• Subjects: Agriculture; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; Climate change; Climate change mitigation; Climate Change/Climate Change Impacts; Crops; Earth and Environmental Science; Emissions; Environment; Environmental monitoring; Fertilizers; Hydrogeology; Impaired water use; Irrigation; Irrigation effects; Irrigation water; Microorganisms; Moisture content; Nitrous oxide; Reclaimed water; Residues; Soil moisture; Soil Science & Conservation; Water Quality/Water Pollution; Water shortages; O losses; Reclaimed water; N fertilizer; N residues; O emissions; N; Water-filled pore space (WFPS)
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-016-2920-1

The use of reclaimed water (RW) for irrigation alleviates agricultural water shortages. However, N 2 O emissions and N fertilizer transformations in soils irrigated with RW under different N fertilizer types and soil moisture contents are poorly understood. A 216-h laboratory incubation experiment was conducted to evaluate the effects of irrigation water types (RW and fresh water, FW), N fertilizer types ( 15 N-labeled KNO 3 and (NH 4 ) 2 SO 4 ), and soil moisture contents at 40, 60, and 90 % water-filled pore space (WFPS) on N 2 O emissions and N fertilizer transformations in intact soil cores. The results showed that cumulative N 2 O emissions ranged from 3.78 to 36.30 mg N m −2 , and fertilizer-derived N 2 O losses accounted for 0.14–2.44 % of N fertilizers, while fertilizer-derived N residues (NO 3 − -N + NH 4 + -N) accounted for 10.16–26.95 % of N fertilizers. The N 2 O emissions at 40 % WFPS and fertilizer-derived N residues at 60 % WFPS in soils irrigated with RW were significantly (10.98 and 20.95 %, respectively) higher than those irrigated with FW, while fertilizer-derived N 2 O losses at 60 % WFPS in soils irrigated with RW were 10.26 % higher than those irrigated with FW. The N 2 O emissions and fertilizer-derived N 2 O losses in soils amended with (NH 4 ) 2 SO 4 at 40 and 60 % WFPS were significantly (26.61–178.84 %) larger than those amended with KNO 3 , while fertilizer-derived N residues in soils amended with KNO 3 were significantly (41.47 %) higher than those amended with (NH 4 ) 2 SO 4 . The N 2 O emissions significantly increased with increasing soil moisture content. Our results indicate that N fertilizer types and soil moisture contents are the two important factors regulating N 2 O emissions and N fertilizer transformations. When RW irrigation is used, controlling soil moisture contents within 41 and 60 % WFPS (the optimum is 46 % WFPS) and application of KNO 3 can reduce N 2 O emissions and fertilizer-derived N 2 O losses, and correspondingly increase fertilizer-derived N residues, which can contribute to climate change mitigation.