Table 3. Analytical methods for measuring soil indicators.

Soil process	Soil indicator	Abbreviation	Methods	Reference
Physical	Soil bulk density	BD	Core method	Clancy et al. (2023)
	Soil water content	WAT	Gravimetric with oven drying method	Almutawa & Eid (2023)
	Soil porosity	POR	Core method	Manoj, Thirumurugan & Elango (2020)
Chemical	Soil organic matter	SOM	Potassium dichromate titrimetric method	Li et al. (2021)
	Total nitrogen	TN	Spectrophotometer method based on the modified Berthelot reaction with an Skalar San++ continuously flowing autoanalyzer	Page, Miller & Kenney (1982), Zhang et al. (2006)
	Available nitrogen	AN
	Total potassium	TK
	Available potassium	AK
	pH	pH	Electrometric method	Liu et al. (2018)
Biological	Urease	URE	10% urea, pH = 6.7, 37 °C, 24 h	Yu et al. (2017)
	Catalase	CAT	Permanganate titration	Johnson & Temple (1964)
	Invertase	INV	3,5-dinitro salicylic acid colorimetry, pH = 5.5, 37 °C, 24 h	Yu et al. (2017)
	Polyphenol oxidase	PPO	Pyrogallol colorimetry, pH = 4.5, 30 °C 2 h	Dogan & Dogan (2004)
	Microbial biomass carbon	MBC	Chloroform fumigation technique	Vance, Brookes & Jenkinson (1987), Brookes et al. (1985), Brookes, Powlson & Jenkinson (1982)
	Microbial biomass nitrogen	MBN
	Microbial biomass phosphorus	MBP