## Seasonality & Sensitivity Of Microbial Decomposition in Semi-Arid Grasslands

Vanessa Pino(1), Amanda Graaf(1), Ella Gambrill(1), Alex McBratney(1), R. Willem Vervoort(1,2)

(1) Sydney Institute of Agriculture & School of Life and Environmental Sciences, The University of Sydney, New South Wales, Australia.
(2) ARC Training Centre in Data Analytics for Resources and Environments.
Corresponding author: Vanessa Pino (vanessa.pino@sydney.edu.au)



This dataset supports research on soil health and landscape restoration in semi-arid grasslands of northern New South Wales, Australia.
It integrates field measurements, laboratory analyses, and remote sensing data to evaluate microbial decomposition and environmental covariates under regenerative grazing practices.

### Tea Bag Index Study
The Tea Bag Index (TBI) method was used to quantify microbial decomposition rates across multiple paddocks. Standardised green and rooibos tea bags were buried for ~54 - 124 days to measure two key parameters:
- **k**: Decomposition rate constant
- **S**: Stabilization factor

These indicators reflect microbial activity and organic matter turnover, offering a responsive metric for soil function. The study examines how decomposition varies in response to soil moisture, temperature, vegetation indices, and land management, positioning TBI as a practical tool for monitoring soil health in dynamic landscapes.

### Landscape Rehydration Project
The Landscape Rehydration (LR) project aims to explore soil and ecological resilience as a function of water management in semi-arid systems. Implemented at Llaras Farm, the project uses rehydration strategies (e.g., contour banks) to slow water movement and increase infiltration. 
Treatments include:
- **Rehydrated paddocks**: Managed with contour interventions
- **Control paddocks**: No intervention

Soil moisture and temperature sensors and soil sampling were used to monitor changes in water cycling, microbial activity, and soil structure. The dataset includes variables such as soil moisture at multiple depths, temperature, vegetation indices (NDVI, EVI), and soil carbon data (CT).

Together, the TBI and LR components will provide a comprehensive monitoring view of how regenerative practices influence soil function and ecosystem resilience.



## *****************************************************DATA CREATORS*****************************************************

**CREATORS:** Vanessa Pino, University of Sydney
**CONTRIBUTORS:** Landscape Rehydration Project Team
**CONTACT:** Dr Vanessa Pino – Researcher
  Email: vanessa.pino@sydney.edu.au

## ********************************************************DATA FILES********************************************************

**FILE NAMES:**
- `SM5\_Tea bag index\_(TBI)\_plus\_soil and environmental covariates (table\_S7).csv`: Main dataset with decomposition metrics and environmental covariates
- `SM5\_Raw tea bag index from calculations (table\_S8)`: the raw tea bag index calculation from replicates (A, B, C, D).
- `SM1\_Data Dictionary\_(table\_S2).csv`: Variable dictionary with acronyms, units, and descriptions.
- `README.md`: Documentation file to data structure.

**ACRONYMS/LABELS:**
- ID	NAME_PROBE	NUM	PROBE_ID	REP_TREATMENT	TREATMENT	TREATMENT_TYPE	SITE	LATITUDE	LONGITUDE	INCUBATION DATE	INITIAL_INC_DATE	FINAL_INC_DATE	DAYS_INC	SET	mean_k	mean_S	sd_k	sd_S	cv_k	cv_S	mean_sm_v1	mean_smacc_v1	mean_sm_v2	mean_smacc_v2	mean_sm_v3	mean_smacc_v3	mean_sm_v2_v3	mean_smacc_v2_v3	sd_sm_v1	sd_sm_v2	sd_sm_v1_v2	sd_sm_v3	mean_rain_v17	mean_rainacc_v17	sd_rain_v17	mean_st_v18	mean_st_v19	mean_st_v20	sd_st_v18	sd_st_v19	sd_st_v20	VerticalCurvature	HorizontalCurvature	slope	hillshade	NDVI_stdDev	EVI_stdDev	DetailedQA_stdDev	sur_refl_b01_stdDev	sur_refl_b02_stdDev	sur_refl_b03_stdDev	sur_refl_b07_stdDev	ViewZenith_stdDev	SolarZenith_stdDev	RelativeAzimuth_stdDev	DayOfYear_stdDev	EVI	ET	amp	pha	depth	total_N_perc_2022	total_C_perc_2022	total_H_perc_2022	CN_ratio_2022	CH_ratio_2022	bd_cyl_gcm3_2022	wetness_cyl_2022	porosity_cyl_2022	vol_sol_cyl_2022	vol_wc_cyl_2022	vol_air_cyl_2022	clay_perc_2021	silt_perc_2021	sand_perc_2021	bd_cor_gcm3_2022	wet_cor_perc_2022	porosity_cor_perc_2022	aggregate_stability_2022	dsDNA_ug of DNA per 1 g of soil_2022	soil_pH_1_5w_2022	EC_dS/m_2022	evap_narrabri	rain_south	rain_wheat	relhumidity_south	relhumidity_wheat	solarrad_south	solarrad_wheat	temp_south	temp_wheat	tempmax_narrabri  tempmin_narrabri  ID_unique NAME_PROBE	ID_TBI	Replicate	Initial weight green tea including bag, cord and label Final weight green tea including dirty bag Initial weight rooibos tea including bag, cord and label Final weight rooibos tea including dirty bag	Decomposition_k	Stabilisation_S	Incubation time (days)	Fraction decomposed green tea	Predicted labile fraction rooibos tea Fraction remaining rooibos tea (Mt)	Fraction decomposed  rooibos tea SET
 
 

**FOLDER STRUCTURE:**
- `/data`: Contains `SM5\_Tea bag index\_(TBI)\_plus\_soil and environmental covariates (table\_S7).csv`, `SM5\_Raw tea bag index from calculations (table\_S8)`
- `/metadata`: Contains `SM1\_Data Dictionary\_(table\_S2).csv`
- `/docs`: Contains `README.md`

## *****************************************************DATA SOURCES*****************************************************

**WHERE:**
Semi-arid grasslands of northern New South Wales, Australia.

**WHEN:**
Data collected during seasonal campaigns between 2021–2024.

**HOW:**
- Tea Bag Index method: standardized green and rooibos tea bags buried for ~ 54 - 124 days following Keuskamp et al., (2013).
- Environmental data from MODIS, Landsat using Google Earth Engine (GEE) and weather stations.
- Soil data from laboratory analysis and in-situ sensors.

**RESOURCES:**
- MODIS LST and NDVI products
- Landsat-derived evapotranspiration
- Field measurements and lab assays

## ****************************************************DATA DEFINITIONS****************************************************

**VARIABLES DEMO: full list in SM1_Data Dictionary_(table_S2)**

| Acronym    | Full Name                              | Unit         | Description                                                 |
|------------|----------------------------------------|--------------|-------------------------------------------------------------|
| TBI_k      | Decomposition rate constant            | day⁻¹        | Rate of mass loss from tea bags over time                   |
| TBI_S      | Stabilization factor                   | unitless     | Fraction of material resistant to decomposition             |
| POXC       | Permanganate-oxidizable carbon         | mgC/kg soil  | Labile carbon pool indicating microbial activity            |
| LST_amp    | Land Surface Temperature Amplitude     | °C           | Seasonal amplitude of LST (sinusoidal fit)                  |
| LST_pha    | Land Surface Temperature Phase         | radians      | Timing of peak temperature (sinusoidal fit)                 |


**CODES:**
- `NA`: Missing data
- Site codes: Unique identifiers for sampling locations - see SM1_Data Dictionary_(table_S2).
- Treatment codes: Grazing regimes or landscape interventions - see SM1_Data Dictionary_(table_S2)

**UNITS:**
- All units specified in the SM1_Data Dictionary_(table_S2)
 

## **********************************************TECHNICAL REQUIREMENTS**********************************************

Not specific requirements.

**FILE FORMATS:**
- `.csv` for tabular data
- `.txt` for documentation
- `.doc` for documentation