Journal Article

impact of nitrogen placement and tillage on NO, N2O, CH4 and CO2 fluxes from a clay loam soil

Mosier, A.R, Halvorson, A.D, Liu, X.J, Zhang, F.S

2006

Overview

To evaluate the impact of N placement depth and no-till (NT) practice on the emissions of NO, N2O, CH4 and CO2 from soils, we conducted two N placement experiments in a long-term tillage experiment site in northeastern Colorado in 2004. Trace gas flux measurements were made 2-3 times per week, in zero-N fertilizer plots that were cropped continuously to corn (Zea mays L.) under conventional-till (CT) and NT. Three N placement depths, replicated four times (5, 10 and 15 cm in Exp. 1 and 0, 5 and 10 cm in Exp. 2, respectively) were used. Liquid urea-ammonium nitrate (UAN, 224 kg N ha-1) was injected to the desired depth in the CT- or NT-soils in each experiment. Mean flux rates of NO, N2O, CH4 and CO2 ranged from 3.9 to 5.2 μg N m-2 h-1, 60.5 to 92.4 μg N m-2 h-1, -0.8 to 0.5 μg C m-2 h-1, and 42.1 to 81.7 mg C m-2 h-1 in both experiments, respectively. Deep N placement (10 and 15 cm) resulted in lower NO and N2O emissions compared with shallow N placement (0 and 5 cm) while CH4 and CO2 emissions were not affected by N placement in either experiment. Compared with N placement at 5 cm, for instance, averaged N2O emissions from N placement at 10 cm were reduced by more than 50% in both experiments. Generally, NT decreased NO emission and CH4 oxidation but increased N2O emissions compared with CT irrespective of N placement depths. Total net global warming potential (GWP) for N2O, CH4 and CO2 was reduced by deep N placement only in Exp. 1 but was increased by NT in both experiments. The study results suggest that deep N placement (e.g., 10 cm) will be an effective option for reducing N oxide emissions and GWP from both fertilized CT- and NT-soils.

• Publisher: Springer,Springer Nature B.V
• Subject: Agronomy. Soil science and plant productions / air temperature / Ammonium / Ammonium nitrate / Biological and medical sciences / Carbon dioxide / Chemical, physicochemical, biochemical and biological properties / Clay loam / clay loam soils / Climate change / continuous cropping / conventional tillage / corn / Cropping systems. Cultivation. Soil tillage / Emissions / Experiments / Fundamental and applied biological sciences. Psychology / gas emissions / General agronomy. Plant production / Global warming / Loam soils / methane / nitric oxide / Nitrogen fertilization / nitrogen fertilizers / Nitrogen, phosphorus, potassium fertilizations / Nitrous oxide / no-tillage / Organic matter / Physics, chemistry, biochemistry and biology of agricultural and forest soils / soil air / Soil science / soil temperature / Soil tillage / soil water / Soil-plant relationships. Soil fertility. Fertilization. Amendments / Tillage / Tillage. Tending. Growth control / Urea / Zea mays