Soil quality in ILF systems, pastures, and native Caatinga evaluated using the multi-trait stability index

Although the multi-trait stability index (MTSI) consists of a multivariate method that was developed for the classification of genotypes regarding performance and stability in multi-environment trials based on multiple traits, our study provides new insights into using MTSI to evaluate soil quality across various land use systems. The objective of this study was to evaluate the impact of converting native vegetation (NV) (dense Caatinga) into an integrated livestock-forestry (ILF) system with gliricidia (Gliricidia sepium) + Urochloa (Urochloa decumbens) (ILFug) under no-tillage, another ILF system with gliricidia + forage cactus (Opuntia cochenillifera) (ILFcg) under conventional tillage, improved pasture (ImpP), and degraded pasture (DegP) on soil quality utilizing the MTSI. Soil samples were collected to a depth of 1m. Soil physical [soil texture, bulk density, macroaggregates, mesoaggregates, microaggregates, soil degree of compactness (SDC), soil stability index (SSI), mean weight diameter (MWD), geometric mean diameter (GMD), aggregate stability index (ASI)], and chemical [pH, P, K, Na, Ca²⁺, Mg²⁺, Al, H, soil organic carbon (SOC), particulate organic matter (POM), and mineral-associated organic matter (MAOM)], were evaluated using the MTSI performed with the "metan" package in the R software. Land uses with lower MTSI values show higher average performance and stability across all the studied variables. The ILFug system achieved the lowest MTSI (5.44), followed by ImpP and NV, with values of 5.51 and 6.04, respectively. These results confirm that MTSI is effective for ranking soil quality in agricultural systems based on the average performance and stability of multiple soil properties across land uses.