Comparative Analysis of Agronomic Management Practices and Soil Physico-Chemical Health Among Smallholder Dairy Farmers Adopting Fodder Crops in South Western Uganda

<title>Abstract</title> <p> Smallholder forage production systems in tropical agroecosystems face severe soil nutrient depletion under continuous cut-and-carry fodder extraction. Evaluating how different soil fertility management regimes influence topsoil chemical and physical properties is critical for designing sustainable soil management interventions. This study evaluated the impact of three soil fertility management regimes Organic (n = 14), Inorganic (n = 16), and Unamended baseline controls on key soil chemical parameters (pH, Organic Matter [OM], Total Nitrogen [TN], Available Phosphorus [P], and exchangeable bases K ⁺ , Ca ²⁺ , Na ⁺ ) and physical parameters (Bulk Density [BD], Sand, Silt, and Clay fractions) across smallholder forage farms in Southwestern Uganda. Both heteroscedasticity-robust Welch’s ANOVA and classical Fisher’s One-Way ANOVA revealed complete statistical homogeneity across all evaluated topsoil chemical properties (p &gt; .306). Tukey’s Honestly Significant Difference (HSD) post-hoc pairwise comparisons confirmed the absence of significant chemical separation between management regimes (padj ≥ .239), indicating that current fertilizer applications occur at sub-threshold, micro-dosed rates that fail to elevate nutrient reserves above baseline levels or overcome native soil buffering and fixation dynamics. Conversely, physical parameter evaluation demonstrated selective, statistically significant structural separation. One-Way ANOVA indicated significant group variance for Sand (F _1,28 = 6.704, p = .015) and Clay (F _1,28 = 4.922, p = .035) fractions. Post-hoc analysis isolated this divergence specifically to the Sand fraction between Inorganic and Organic fields (Delta = +9.259%, SE = 3.571, padj = .032, 95% CI [+0.649, +17.869]), along with a corresponding inverse trend in Clay content (Delta = -6.402%, padj = .076). Bulk density (padj ≥ .227) and silt content (padj ≥ .551) remained invariant across regimes. Because particle-size distributions are recalcitrant pedological attributes, this textural separation reflects a strategic spatial allocation strategy by smallholders: commercial inorganic inputs are preferentially targeted to coarser, sand-dominated soils to offset low native nutrient retention, whereas bulky organic manure is concentrated on clay-rich fields near homestead kraals. These findings underscore that current soil management operates as low-dose input substitution rather than soil building, highlighting the imperative for Integrated Soil Fertility Management (ISFM) strategies that combine targeted mineral fertilization with organic additions to sustain long-term forage productivity. </p>