Readme file for Khan_etal_2025_Nitrousoxide_Multispecies.xlsx

Title: Effects of grassland community composition and digestate fertiliser on nitrous oxide emissions from soil

Authors: Ali S Khan, John A Finn, Alexandre B de Menezes, Dominika J Krol

Corresponding email: Dominika.krol@teagasc.ie

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The associated Excel file contains data on nitrous oxide emissions, nitrogen yield scaled nitrous oxide emissions intensity, and nitrous oxide emissions factor for sown grasslands comprising four plant communities: perennial ryegrass monoculture; perennial ryegrass with white clover; perennial ryegrass with red clover, and; a six-species mixture of Perennial ryegrass, timothy, white clover, red clover, chicory, and ribwort plantain. These grassland communities received either high, low, or no nitrogen. When applied, nitrogen was in the form of digestate or calcium ammonium nitrate, and nitrous oxide emissions were measured using static chambers.

The experiment was established at Teagasc, Johnstown Castle, Wexford, Republic of Ireland (lat. 52.295364, long. -6.508217) in 2021.
Data was collected between April 2022 and April 2024
Date of file creation: 05/12/2024

Plant communities: Perennial ryegrass; perennial ryegrass with white clover; perennial ryegrass with red clover; and an equi-proportional mixture of perennial ryegrass, timothy, white clover, red clover, chicory, and ribwort plantain.

Nitrogen levels: In year 1, nitrogen application rates were 50 and 100 kg N per ha per year from CAN, and 25 and 50 kg N per ha per year from digestate. 
		 In year 2, nitrogen application rates were 50 and 100 kg N per ha per year from both CAN and digestate.

Nitrogen Sources: Digestate and CAN

These data support the research results presented in Journal of Environmental Management, https://doi.org/10.1016/j.jenvman.2025.127125

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Dataset contains:
-    120 observations (rows) + 1 row header

-    10 variables (columns)

-    Column delimiter = ,

-    Missing value = -

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Variables		Format			Explanation

Plot			numeric			Plot number as identifier of experimental units (plots in the field experiment)
Year			numeric			Two time periods; Year '1' is 2022-23 and Year '2' is 2023-24
Nsource			Alphabet		Nitrogen fertiliser sources with two sources ('Dig' = digestate and 'Inorg' = CAN) and 'None' to represent the control with no nitrogen application.
NLvl			numeric			Nitrogen application levels. 
							For digestate, 'LowN' = 25 kg N per ha per year in year 1 and 50 kg N per ha per year in year 2, 
							'HighN' = 50 kg per ha per year in year 1 and 100 kg N per ha per year in year 2. 
							For calcium ammonium nitrate (CAN), 'LowN'  = 50 kg N per ha per year and 'HighN' = 100 kg N per ha per year in both years) and 
							'ZeroN' = control that received neither digestate nor CAN.
Plantsp			Alphabet		Description of the different plant communities. 
							'PRG' = perennial ryegrass, 
							'PRG+WC' = perennial ryegrass with white clover, 
							'PRG+RC' = perennial ryegrass with red clover, 
							'MIX' = six-species mixture, which was sown as an equi-proportional mixture of perennial ryegrass, timothy, white clover, red clover, chicory, and ribwort plantain	
N2O			numeric			Cumulative nitrous oxide emissions in the study period (g N2O-N per ha per year)
N2O_SE			numeric			Standard error for nitrous oxide emissions, calculated across the replicate values for each treatment combination. The same SE value is presented for each treatment combination 
						(for presentation of error bars in the graphs) 
EI_NBIOM		numeric			Nitrous oxide emissions intensity. Values represent nitrous oxide emissions scaled by nitrogen yield (g N2O-N per ha per year/kg nitrogen yield per ha per year)
EI_NBIOM_SE		numeric			Standard error for nitrous oxide emissions intensity, calculated across the replicate values for each treatment combination. The same SE value is presented for each treatment combination 
 						(for presentation of error bars in the graphs) 
EF			numeric			Nitrous oxide emissions factor (%)
