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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Publications at this Location » Publication #306790

Research Project: Developing Sustainable Cropping Systems to Improve Water Productivity and Protect Water and Soil Quality in Irrigated Agriculture

Location: Water Management Research

Title: Evaluation of factors affecting nitrous oxide emission and N transformation in a sandy loam soil

Author
item Cai, Zejiang - Chinese Academy Of Agricultural Sciences
item Gao, Suduan
item Hendratna, Aileen
item Duan, Yinghua - Chinese Academy Of Agricultural Sciences
item Xu, Minggang - Chinese Academy Of Agricultural Sciences
item Hanson, Bradley - University Of California

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/28/2014
Publication Date: 11/2/2014
Citation: Cai, Z., Gao, S., Hendratna, A., Duan, Y., Xu, M., Hanson, B. 2014. Evaluation of factors affecting nitrous oxide emission and N transformation in a sandy loam soil. Meeting Abstract. Abstract CD #248-13.

Interpretive Summary:

Technical Abstract: A better understanding of the complex factors affecting nitrous oxide (N2O) emission and potential mitigation practices will assist in developing strategies to improve the sustainability of agricultural production systems. Using surface soil collected from a pomegranate orchard, a series of laboratory experiments were conducted to investigate the effect of nitrogen (N) application rate, soil water content, temperature, biochar amendment, and N transformation inhibitors on N2O emission and associated N transformations. Treatments included several different urea application rates [0, 50, 100, 150 mg N kg-1 at 10% water content (w/w)], soil water content (5%, 10%, 20% and 30% with 100 mg N kg-1 applied), temperature (10, 25 and 40 degrees Celsius with 150 mg N kg-1 applied), incorporation of biochar (1%, w/w), an urease inhibitor (Agrotain® Ultra), and a nitrification inhibitor (N-Serve® 24) with 150 mg N kg-1 applied. All soils were incubated at 25 degrees Celsius except for the different temperature treatments. Soil mineral N concentrations and pH as well as N2O emissions were monitored. Total N2O emission rose significantly with increasing N rates and temperature. Higher soil water content at 20% and 30% resulted in much higher total N2O emission (11.63 and 13.01 mg N2O-N kg-1, or 11.6% and 13.0% of applied N, respectively) than that from 5% and 10% water content (0.26 and 0.33 mg N2O-N kg-1, respectively). Amendment with biochar, the urease inhibitor, and the nitrification inhibitor reduced N2O emission by 75%, 83% and 77%, respectively, as compared with unamended soil (1.04 µg N2O-N kg-1). Changes in soil mineral N and pH suggested a delay in urea-N hydrolysis with the urease inhibitor and the nitrification inhibitor. The results indicate that N2O emission is highly affected by the environmental factors, and biochar or N transformation inhibitors can be effective in mitigating N2O emission.