Fig. 2: Effects of warming and management on soil attributes and soil health score at 0-5 cm soil depth.
From: Conservation agriculture improves soil health and sustains crop yields after long-term warming
a Two dimensions of Principal Component Analysis (PCA) for eigenvalues of the seventeen soil attributes, including MWD, R0.25, SM, BD, pH, DOC, SOC, NH4+-N, NO3--N, DON, TN, AP, TP, AK, TK, MBC, and MBN. All parameters were analyzed based on soil sampling in 2020 (n = 4 independent soil samples per treatment). b Effects of warming and management on soil health score. Data are presented with mean values ± s.e.m. Statistical analysis was performed using two-way ANOVA analysis. Soil health score was evaluated based on soil sampling in 2020 (n = 4 independent soil samples per treatment). c Estimates of the warming effects on soil attributes depending on management. The effect size was estimated by Cohen’ d. Data are presented with mean values ± s.e.m. Statistical analysis was performed using two-way ANOVA analysis (n = 4 independent soil samples per treatment). d–g Average of key soil attributes over eight years determined using a linear mixed model. Statistical significance is based on Wald type II χ² tests (n = 24 independent soil samples per treatment). Boxplots display the mean (horizontal line), the 25th and 75th percentiles (colored box), the minimum and maximum (whiskers). h–k Temporal changes of warming effects on key soil properties over time depending on management. The effect size was estimated by Cohen’ d. The solid line represents the significant linear regression (P < 0.05), and the gray shading indicates the 95% confidence interval (i.e., error bands represent slopes ± 95% confidence intervals). All reported P values result from two-sided statistical tests where *P < 0.05, **P < 0.01, and ***P < 0.001. Conserv-Amb, conservation agriculture without warming; Conserv-Warm, conservation agriculture with warming; Conven-Amb, conventional agriculture without warming; Conven-Warm, conventional agriculture with warming. MWD, mean weight diameter; R0.25, aggregate content with particle size larger than 0.25 mm; SM soil moisture, BD bulk density, DOC dissolved organic carbon, SOC soil organic carbon, NH4+-N ammonium, NO3−N nitrate, DON dissolved organic nitrogen, TN total nitrogen, AP available phosphorus, TP total phosphorus, AK available potassium, TK total potassium, MBC microbial biomass carbon, MBN microbial biomass nitrogen. Source data are provided as a Source Data file.
