Soil physical quality index under long‐term organic no‐tillage management in central Ohio

Understanding how long‐term organic inputs and no‐tillage (NT) management influence soil physical quality (SPQ) is essential for sustainable agriculture. This study assessed the impacts of compost, manure, and cover cropping on the soil physical quality index (SPQi) after 27 years of NT management under a long‐term cropping system in central Ohio. We hypothesized that compost would yield the highest SPQi due to its stable organic matter content and structural benefits. SPQi was derived from five key indicators: penetration resistance (PR), saturated hydraulic conductivity, plant available water capacity, water‐stable aggregates (WSA), and soil organic carbon (SOC), using principal component analysis to compute indicator weights based on their contribution‐derived importance to multivariate variance. These weights were subsequently used to normalize and integrate the indicators into a composite index that reflects overall SPQ across treatments and depths. Soil samples were collected from two depths (0–20 and 20–40 cm). Indicator weights were then used for normalization and classification of SPQi. Treatment effects were evaluated using analysis of variance and regression analysis. Compost‐treated plots showed the highest mean SPQi values at both depths (0.63 ± 0.12 at 0–20 cm and 0.64 ± 0.18 at 20–40 cm), followed by manure, while cover crop consistently exhibited the lowest values (0.26 ± 0.14 at 0–20 cm). SOC emerged as the primary driver of SPQi, showing strong positive correlations with WSA ( R 2 = 0.76, p < 0.001) and a moderate inverse correlation with bulk density ( R 2 = 0.32, p < 0.001). PR was highest under cover crop (1.88 ± 0.08 MPa), indicating surface compaction. These findings indicate that long‐term compost and manure applications under NT enhance soil physical function. SPQi proved effective in integrating multiple indicators, offering a robust tool for evaluating soil health. Compost, in particular, showed strong potential for optimizing SPQ in temperate NT systems.