sqi_fuzzy: Soil Quality Index: Fuzzy Logic Method

In SQIpro: Comprehensive Soil Quality Index Computation and Visualization

Soil Quality Index: Fuzzy Logic Method

Description

Computes SQI using a fuzzy membership aggregation approach. Each scored variable (already 0–1) is treated as a fuzzy membership value, and groups are aggregated using either the arithmetic mean (equivalent to the linear method) or the fuzzy weighted average operator.

This approach is appropriate when variable importance is uncertain or when expert-elicited weights are available (Zhu et al., 2006; Torbert & Wood, 1992).

Usage

sqi_fuzzy(
  scored,
  config,
  group_cols = "LandUse",
  mds_vars = NULL,
  fuzzy_weights = NULL,
  operator = c("mean", "geometric")
)

Arguments

scored	A scored data frame from score_all.
config	A sqi_config object.
group_cols	Character vector of grouping column names.
mds_vars	Character vector of MDS variable names.
fuzzy_weights	Named numeric vector of fuzzy importance weights (sum need not equal 1; they are normalised internally). Defaults to equal weights.
operator	Character. Aggregation operator: "mean" (default) or "geometric" (product-based, penalises low scores on any variable).

Value

A data frame with group columns and SQI_fuzzy (0–1).

References

Zhu, A.X., Liu, F., Li, B., Pei, T., Qin, C., Liu, G., Wang, Y., Chen, Y., Ma, X., Qi, F., & Li, R. (2010). Differentiation of soil conditions over flat areas using land surface feedback dynamic patterns extracted from MODIS. Soil Science Society of America Journal, 74(1), 861–869.

Torbert, H.A., & Wood, C.W. (1992). Effects of soil compaction and water-filled pore space on soil microbial activity and N losses. Communications in Soil Science and Plant Analysis, 23, 1321–1331. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1080/00103629209368668")}

Examples

data(soil_data)
cfg <- make_config(
  variable = c("pH","EC","BD","OC","MBC","Clay"),
  type     = c("opt","less","less","more","more","opt"),
  opt_low  = c(6.0, NA, NA, NA, NA, 20),
  opt_high = c(7.0, NA, NA, NA, NA, 35)
)
scored <- score_all(soil_data, cfg, group_cols = c("LandUse","Depth"))
result <- sqi_fuzzy(scored, cfg, group_cols = c("LandUse","Depth"))
print(result)

SQIpro documentation built on April 20, 2026, 5:06 p.m.