Soil pH and its relationship with nutrient status from different soil types in black soil region of Jilin Province

Soil pH and nutrients are important indicators of soil quality and health, while clarifying pH and nutrient characteristics of different types of soils can provide a scientific basis for protecting soil resources. The five main types of soils in the black soil zone of Jilin Province-albic leached soils, typical Mollisols and Chernozem (all Isohumosols), meadow soils, and paddy soils-were chosen to study the relationships of pH with soil organic matter (SOM), total nitrogen (TN), and total phosphorus (TP), and their influencing factors. The results show that: soil pH in the black soil area of Jilin Province ranges from 5.31 to 8.30, with 47.3% of the slightly acidic grade and 35.2% of the neutral grade, and the mean value of meadow soil pH is 7.10% to 16.7% higher than that of other types of soils. SOM content ranges from 10.9 to 61.0 g·kg⁻¹, with 47.3% of the moderate grade and 46.2% of the richer grade, and the mean value of the typical black soil SOM content mean value is 5.90% - 36.4% higher than other soils. No significant differences of TN and TP contents are found among the five soils. Binary regression analysis shows that the pH of black calcareous soil and meadow soil fit with TN and TP highly (P<0.05), and the TN and TP contents both increase with the increase of pH. Pearson correlation analysis shows that the soil pH and the TN content are positively correlated, while SOM is positively correlated with TN and TP, soil pH is negatively correlated with rainfall amount and fertilizer application rate (P<0.01) but not significantly correlated with SOM content, TN is negatively correlated with rainfall amount (P<0.01). The pH value of the black soil area in Jilin Province is mostly in the slightly acidic and neutral class, and the increase of rainfall and fertilizer application promote soil acidification. Scientific regulation of soil water and fertilizer application system for albic leached soils, Chernozems and paddy soils are required to curb soil acidification and nutrient loss in actual production practices.