Abstract: In this work, 120 soil samples were collected from the Taige Canal valley, and the number of samples for paddy field, irrigated field, orchard land, forestland and wasteland were 45, 18, 25, 22 and 10, respectively. In order to enhance the soil farmland fertilizer management and non-point source pollution control, contents and spatial distribution characteristics of pH, soil organic matter (SOM), total nitrogen (TN) and total phosphorus (TP) under different land use types were analyzed by using mathematical statistics and ArcGIS technology. Results indicate that:(1) All the studied soils were acidic with an average pH of 5.36. The TN and SOM were abundant while TP was relatively deficient, which corresponded to the level two, level two and level five, respectively, according to the nutrient classification standards of the second national soil survey. In addition, the differences in soil pH, TN and SOM contents under different land use types were highly significant (P<0.01). The pH values were in the following sequence:wasteland > paddy field > forest land > irrigated land > orchard land; and TN content gave the following sequence:paddy field > irrigated land > orchard land > forest land > wasteland; whereas SOM content decreased in the following sequence of paddy field > orchard land > irrigated land > forest land > wasteland. These differences were probably due to the differences in type and application dosage of chemical fertilizers, planting system, vegetation coverage, and farming management. However, no significant differences were found in soil TP contents among the five land use types, which might be attributed to the single fertilization, soil phosphorus leaching and loss. (2) Spearman correlation analysis among soil nutrients show that TN had a negative correlation with pH value (P<0.05), but exhibited a significant positive correlation with SOM and TP. (3) Under different land types, the soil pH exhibited small variation to medium variation. TN and SOM showed moderate variation. TP for all the land types had high variation except for wasteland. The acidic soils were distributed widely and regularly in the Taige Canal valley. The high levels of TN and SOM were mainly concentrated in the middle and lower reaches of Taige Canal, while the high content areas of TP were concentrated in the south side of the middle and lower reaches.

Key words: Taige Canal valley, agricultural nonpoint source pollution, land use types, soil nutrient