Aggregate Indices Method in Soil Quality Evaluation Using the Relative Soil Quality Index

Table 2

Converting hierarchy for assessing criterion to hierarchy for assessing SQ for the group of total content of bioelements.

Parameter	Criterion (%)	Hierarchy	Reference	Hierarchy for SQ ∈ [, ] (%)	SQ
SOM	>2.5	High		>2.5	Good
	1.25–2.5	Medium	Nguyen [8]	1.25–2.5	Moderate
	<1.25	Low		<1.25	Poor
Total N	>0.2	Rich		>0.2	Good
	0.1–0.2	Moderate	Nguyen [11]	0.1–0.2	Moderate
	<0.1	Poor		<0.1	Poor
Total P	>0.1	Rich		>0.1	Good
	0.06–0.1	Moderate	Le [9]	0.06–0.1	Moderate
	<0.06	Poor		<0.06	Poor
Total K	>2	Rich		>2	Good
	1-2	Moderate	Tran [10]	1-2	Moderate
	<1	Poor		<1	Poor