| 摘要 | Soil stability is a characteristic property and is frequently used as an indicator of soil quality. Considering the
large variation among stability tests, existing studies usually employ more than one stability test in order to
better understand soil behavior against various disruptive forces. The main purposes of this study were to
evaluate the impact of aggregate disruptive mechanisms (slaking, clay swelling, mechanical breakdown, and
cavitation) on soils developed under different plant species. We aimed as well to compare the results of three
renowned soil stability methods: modified Yoder (Yod), Le Bissonnais (LB) and Ultrasonic agitation (UA) on
surface (0–20 cm) and subsurface (20–40 cm) soils. Overall, soils of three plant communities developed under
eight plant species were investigated. These include forestland (Quercus wutaishansea, Pinus tubulaeformis, Pla-
tycladus orientalis, and Robinia pseudoacacia), shrubland (Sophora viccifolia, Hippophae rhamnoides, and Rosa
xanthina) and grassland (Stipa bungeana). The mean weight diameter (MWD) was used as a stability parameter for
modified Yoder’s and Le Bissonnais’ methods. In contrast, specific dispersion energies (SE) at the initial (10%, w/
w), middle (50%, w/w) and final (90%, w/w) stages of aggregate disruption were used as stability parameters by
the UA method. The results of MWD (Yod) indicated that surface and subsurface soils were in the range of
1.23–2.86 mm, which accounted for medium (0.8–1.3 mm) to very stable (>2 mm) soils. Among the three LB
tests (fast wetting (FW), slow wetting (SW), and wet stirring (WS)), the order of aggregate disruption was FW >
WS > SW, suggesting that FW was the most destructive among the three tests with the lowest MWD value (0.45
mm, unstable soil). SW showed the highest MWD values (0.82–2.82 mm), and most of the soils were ranked in
the stable (1.3–2 mm) to very stable (>2 mm) range. The MWD trend of WS was similar to FW test. Although the
range of SE at three levels was different: SE 10 (8.1–29.4 J g −1 ), SE 50 (53.0–193.4 J g −1 ), and SE 90 (176–642 J
g −1 ), they all showed a similar association with soil characteristics and stability parameters of other tests. The
strong positive correlation of soil organic carbon (SOC), total nitrogen (TN), fine root biomass (FRB), and clay
contents, and the negative correlation of soil water content (SWC) with the five tests, indicated that these five
factors were the major characteristics responsible for the resistance of the studied soils against different
destructive mechanisms (p < 0.05–0.01). Overall, the results of all five tests indicated that soil under Quercus
wutaishansea (QW) was the most stable, while that under Robinia pseudoacacia (RP) was the most unstable.
Although all methods were based on different breakdown mechanisms, initial and final soil fractions and pa-
rameters, they were strongly positively correlated with each other. This indicated that all these tests were equally
good at stability assessment, with some distinctions and limitations. |
修改评论