Unexpected microbial metabolic responses to elevated temperatures and nitrogen addition in subarctic soils under different land-use

This repository contains all necessary raw data as well as the R code used to conduct statistical analysis and create figures of the publication Unexpected microbial metabolic responses to elevated temperatures and nitrogen addition in subarctic soils under different land-use
Julia Schroeder1, Tino Peplau1, Edward Gregorich2, Christoph C. Tebbe3, Christopher Poeplau1
1 Thünen Institute of Climate-Smart Agriculture, Bundesallee 68, 38116 Braunschweig, Germany2 Research and Development Centre, Central Experimental Farm, Agriculture and Agri-Food Canada, Ottawa, Canada3 Thünen Institute of Biodiversity, Bundesallee 65, 38116 Braunschweig, Germany
DOI: https://doi.org/10.1007/s10533-022-00943-7 
This study investigated how subarctic soils under different land use will respond to warming and increasing N availability to allow for better predictions of C cycling under global change. The short-term temperature sensitivity as well as N-input effects on microbial CUE, respiration, growth and turnover were assessed in a one-day incubation experiment according to the 18O-CUE approach. The warming and N response of SOM decomposition were assessed in a 50-days incubation experiment via measurement of cumulative respiration. Both experiments were conducted with the following three treatments: incubation at 10 °C, incubation at 20 °C, and incubation at 20 °C plus N-fertiliser addition at an amendment rate of 100 kg N ha-1. The response to warming or N addition were expressed as response ratios RRT = 20°C/10°C and RRN = 20°C+N/20°C for warming and N response, respectively.
The R code was developed under R v3.6.3 and adapted to work under version R v.4.1.2.
The repository includes the following files:

general_soil_parameters_per_sample.csv - general soil data for each field sample (n=27)
general_soil_parameters_per_plot.csv - general soil data assessed on pooled replicated field samples (n=9)
respiration_over_50d_incubation.csv - respiration rate and cumulative respiration for each time-point and laboratory sample over the 50-days incubation
sample_data.csv - data measured for each laboratory sample (n=81)

Warming_and_nitrogen_response_of_CUE_in_subarctic_soils.Rproj - Rproject (load project to work on provided scripts and data)
load_data_script.R - loads required data
absolute_values_script.R - summary of absolute ranges of parameters per land-use type and site
absolute_linear_mixed_effects_model_script.R - run statistical analysis
correlograms_absolute_soil_params_script.R - correlation analysis to identify what drives absolute values
plot_correlations_absolute_soil_params_script.R - plot drivers of CUE and cumulative respiration
RRT_RRN_calculation_script.R - calculates response ratios
plot_RRT_RRN_script.R - plot response ratios
RRT_RRN_linear_mixed_effects_models_script.R - run statistical analysis
correlograms_RRT_RRN_soil_param_script.R - correlation analysis to identify drivers of response ratios
plot_correlations_RRT_RRN_soil_params_script.R - plot drivers of response ratios
RRT_RRN_resprate_cumulresp_over_time_50d_incubation_script.R - plot response ratios over time course