Finding the optimal fertilizer type and rate to balance yield and soil GHG emissions under reclaimed water irrigation

Yanbing Chi; Peiling Yang; Shumei Ren; Jing Yang

doi:10.1016/j.scitotenv.2020.138954

Finding the optimal fertilizer type and rate to balance yield and soil GHG emissions under reclaimed water irrigation

Sci Total Environ. 2020 Aug 10:729:138954. doi: 10.1016/j.scitotenv.2020.138954. Epub 2020 Apr 28.

Authors

Yanbing Chi¹, Peiling Yang², Shumei Ren¹, Jing Yang¹

Affiliations

¹ College of Water Resources & Civil Engineering, China Agricultural University, No. 17 Tsinghua East Road, Haidian District, 100083 Beijing, China.
² College of Water Resources & Civil Engineering, China Agricultural University, No. 17 Tsinghua East Road, Haidian District, 100083 Beijing, China. Electronic address: yang-pl@163.com.

PMID: 32387773
DOI: 10.1016/j.scitotenv.2020.138954

Abstract

Water and inorganic nitrogen fertilizer have a notable impact on crop yield and greenhouse gas (GHG) emissions from soil. Reclaimed water (RW) is widely used for irrigation when there are shortages of water resources. It is very important to control yield and greenhouse gas emissions by fertilization under reclaimed water irrigation (RWI). The study consisted of a continuous test that evaluated three types of fertilizer treatments (urea, amine, and slow-release fertilizer) and a no-fertilizer treatment under three-year RWI and four fertilizer levels (150, 200, 250 and 300 kg.N.ha^-1) under one-year RWI to determine the best fertilizer to support maize production and reduce GHG (CO₂ and N₂O) emissions from soil; further, the applicability of RWI in the DNDC model was verified. For many years, GHG emissions under RWI showed an increasing trend, but the effect was not significant. A strong correlation was found between the GHG emissions flux and fertilizer amount, and a threshold fertilization amount existed between 220 and 260 kg.N.ha^-1 that minimized yield-scaled N₂O emissions and the ratio of GHG cumulative emission to yield (GHG/Y). The results indicated that the optimal amounts of SF and UF under RWI were 240 and 225 kg.N.ha^-1 by second-order equation and the DNDC model, respectively, and the rate better balanced the yield and GHG emissions.

Keywords: DNDC; Fertilizer; GHG; Reclaimed water; Yield.