摘要
Soil aggregate stability,an important index of the physical characteristics of a soil,can provide a good indication of a soil’s erodibility,and deserves special consideration in regions with cold climate.The objective of this study was to study the effect of freeze-thaw on soil water-stable aggregates in the black soil region of Northeast China.Samples of a typical black soil in the region were collected to measure water-stable aggregates after freeze-thaw under different conditions(i.e.,initial moisture contents,freezethaw cycles and freezing temperatures)by wet-sieving into eight particle size groups(>10,10–6,6–5,5–3,3–2,2–1,1–0.5,and0.5–0.25 mm).Freeze-thaw had the most effect on aggregate stability when the samples had an initial moisture content of 400 g kg-1.The water-stable aggregates of the four larger particle size groups(>5,5–3,3–2,and 2–1 mm)reached a peak stability value,but those of the two smaller particle size groups(1–0.5 and 0.5–0.25 mm)reached a minimum value when the soil moisture content was 400 g kg-1.Water-stable aggregates of the four larger particle size groups decreased while those of the two smaller particle size groups increased with the increase of freeze-thaw cycles.As temperatures fell,the water-stable aggregates of the four larger particle size groups decreased while those of the two smaller particle size groups increased.
Soil aggregate stability, an important index of the physical characteristics of a soil, can provide a good indication of a soil＇s erodibility, and deserves special consideration in regions with cold climate. The objective of this study was to study the effect of freeze-thaw on soil water-stable aggregates in the black soil region of Northeast China. Samples of a typical black soil in the region were collected to measure water-stable aggregates after freeze-thaw under different conditions （i.e., initial moisture contents, freeze- thaw cycles and freezing temperatures） by wet-sieving into eight particle size groups （〉 10, 10 6, 6-5, 5-3, 3 2, 2-1, 1-0.5, and 0.5-0.25 mm）. Freeze-thaw had the most effect on aggregate stability when the samples had an initial moisture content of 400 g kg-1. The water-stable aggregates of the four larger particle size groups （〉 5, 5 3, 3 2, and 2-1 mm） reached a peak stability value, but those of the two smaller particle size groups （1 0.5 and 0.5-0.25 mm） reached a minimum value when the soil moisture content was 400 g kg-1. Water-stable aggregates of the four larger particle size groups decreased while those of the two smaller particle size groups increased with the increase of freeze-thaw cycles. As temperatures fell, the water-stable aggregates of the four larger particle size groups decreased while those of the two smaller particle size groups increased.
基金
Supported by the National Natural Science Foundation of China(Nos.41071183 and 40601054)
