Soil degradation poses a threat to agricultural productivity and environmental sustainability. Intensive use, mechanical disturbances, and inappropriate practices deteriorate soil structure, reducing its water retention capacity, resistance to erosion, and support for plant growth. A key indicator of this physical degradation is structural stability, assessed using the dispersion ratio (DR), which reflects the soil’s resistance to disintegration. The objective of this study was to evaluate the effects of the spatial distribution of soil structural stability, as well as the influence of management practices, in three land use systems (conventional, organic, and fruit) in La Molina, Lima, Peru. In an area of 120,000 m ² , 100 georeferenced points (0–20 cm deep) were sampled, analyzing particle size distribution, bulk density (BD), and DR. Spatial variability was characterized using geostatistical interpolation (kriging), generating gradient maps. Differences between systems were evaluated using the Games–Howell test, which is suitable for nonhomogeneous variances. The results showed sandy loam texture in all fields and significant differences in DR, with marked spatial dependence. Spatial trend analysis revealed a deterministic component, justifying the use of universal kriging (UK). The spherical (Sph) semivariogram model was the best fit. Cross‐validation (ME = −0.067; RMSE _ep = 7.13; MSDR = 1.3) indicated accurate and unbiased predictions. Soils under fruit crop fields exhibited greater structural stability, whereas soils under organic and conventional management systems showed medium to low aggregate stability. In addition, a negative correlation was observed between BD and DR, suggesting that BD is not a good indicator of aggregate formation. Spatial positioning and agricultural management significantly influence soil structural stability, with less intensive practices favoring its conservation.

Soil organic matter (SOM) is a key indicator of soil quality due to its impact on physical, chemical, and biological properties. The standardized method in Peru for determining SOM is wet oxidation, which requires the use of controlled chemical reagents; however, their improper disposal poses a risk of environmental contamination. As an alternative, the calcination method can be used, which is less polluting, although the operating temperatures have not yet been standardized nationwide. The aim of this research is to compare the calcination method at three different ignition temperatures with the standardized method. A total of 61 soil samples from various regions of Peru, exhibiting different SOM and CaCO₃ contents, were analyzed. Calcination temperatures were set at 400 °C, 500 °C, and 600 °C. The results compared SOM determined by wet oxidation and SOM determined by calcination using the Wilcoxon test, which showed significant differences (p < 0.05). Linear regression equations were developed to evaluate the correlation between both procedures, and SOM obtained by calcination at the three temperatures showed a strong linear correlation (adjusted R² = 0.88). Among the regression equations for each calcination temperature, the 400 °C treatment exhibited the highest correlation with the standardized method (adjusted R² = 0.92, p < 0.005). These findings suggest that the calcination method at 400 °C can be a useful approach to estimate soil organic matter content across different soil types.

Nitrogen fertilization in flooded rice systems can promote nitrate leaching and groundwater contamination, particularly where groundwater is used for human consumption. This study aimed to assess soil susceptibility to nitrate leaching toward groundwater in rice-growing areas of Rioja, San Martín, Peru. Sampling was based on a semidetailed soil map of the Rioja sector, from which 14 soil series were identified; one georeferenced point was established per series, with soil collected at two depths (0–20 and 20–40 cm). From these points, four representative soil profiles were selected through a Delphi consensus process and classified as Typic Endoaquepts (P1 and P2), a Typic Endoaquoll (P3), and a Fluventic Endoaquept (P4). The 28 saturated hydraulic conductivity (Ks) measurements were used to develop a local pedotransfer function, in which the inverse of bulk density was the main predictor of Ks. Profile-specific Ks estimates were incorporated into HYDRUS-1D to simulate nitrate transport under an identical fertilization regime over 10 years. Ks averaged 0.21 cm·h⁻¹ with high variability (CV = 84.12%), and the pedotransfer function explained 42.9% of this variability (R²adj = 0.383, RMSE = 0.127 cm·h⁻¹). Despite receiving identical fertilizer inputs, the four profiles showed simulated nitrate transport differing by up to 19.9%, driven by differences in soil hydraulic properties and profile structure rather than by management practices. Flow-weighted mean nitrate concentrations at the lower model boundary ranged from 48.33 to 57.96 mg·L⁻¹; two profiles (P4 and P1) exceeded the 50 mg·L⁻¹ WHO guideline, reflecting a greater leaching risk in soils that are more stratified and have higher hydraulic conductivity, while the profile with the highest organic carbon content (P3) showed lower susceptibility, likely due to greater denitrification. These findings indicate that local soil properties are a key control on nitrate leaching susceptibility, supporting the need for soil-type-specific nitrogen management to protect groundwater resources.

The method used to measure Cation Exchange Capacity (CEC) affects its interpretation. Soil labs often use potential CEC (pCEC) and effective CEC (ECEC) interchangeably, without clarifying their conceptual differences or the steps involved in each method. Analyses use solid fractions but do not distinguish between specific procedures or method variables. It is important to specify procedural differences—such as extraction pH, extractant used, and the cation quantified—and quantify their effects on CEC measurement and on the interpretation of the roles [...] ABSTRACT The method used to measure Cation Exchange Capacity (CEC) affects its interpretation. Soil labs often use potential CEC (pCEC) and effective CEC (ECEC) interchangeably, without clarifying their conceptual differences or the steps involved in each method. Analyses use solid fractions but do not distinguish between specific procedures or method variables. It is important to specify procedural differences—such as extraction pH, extractant used, and the cation quantified—and quantify their effects on CEC measurement and on the interpretation of the roles