Phytosanitary practices, soil physicochemical quality patterns, and environmental risk assessment in pesticide-treated agricultural fields of Western Algeria

Pesticides remain central to crop protection and agricultural productivity, but inappropriate application practices may increase environmental and occupational risks. This study provides an integrated assessment of phytosanitary practices, soil physicochemical quality patterns, and Tier 1 environmental risk in pesticide-treated agricultural fields of western Algeria. A semi-structured survey was conducted in 70 agricultural fields across Oran, Mostaganem, Ain Temouchent, and Saida to document pesticide use patterns, active ingredients, treated crops, dose compliance, and safety practices. Soil physicochemical properties were assessed in 20 pesticide-treated plots and 20 corresponding untreated control samples. For each plot, one composite soil sample of approximately 1 kg was obtained from the 0–40 cm layer by pooling six subsamples collected along a complete zigzag transect. Tier 1 environmental risk was evaluated by estimating predicted environmental concentrations (PEC soil) and chronic toxicity-exposure ratios (TER) following EFSA guidance and the FAO Pesticide Registration Toolkit. Soil data were analyzed using descriptive statistics, paired treated-control comparisons, Shapiro-Wilk normality tests, paired t-tests or Wilcoxon signed-rank tests as appropriate, false discovery rate adjustment, Spearman correlation, and standardized principal component analysis. The survey showed a predominance of insecticides and fungicides, frequent noncompliance with recommended application rates, and limited use of personal protective equipment. Compared with the corresponding controls, treated soils showed significantly lower moisture and organic matter, higher pH, and lower silt content after FDR correction, whereas electrical conductivity, carbonate variables, available phosphorus, clay, and sand did not show robust paired differences. Multivariate analysis separated samples mainly according to moisture, pH, organic matter, carbonate status, texture, and available phosphorus. The Tier 1 assessment identified sites with potential chronic risk requiring further refinement or risk mitigation. These findings provide a regional baseline on phytosanitary practices, soil physicochemical patterns, and screening-level environmental risk in western Algerian agroecosystems.