Aggregate binding agents improve soil aggregate stability in Robinia pseudoacacia forests along a climatic gradient on the Loess Plateau, China
JING Hang1, MENG Min1, WANG Guoliang1,2, LIU Guobin1,2,*()
1State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China 2Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Yangling 712100, China
The distribution of binding agents (i.e., soil organic carbon (SOC) and glomalin-related soil protein (GRSP)) in soil aggregates was influenced by many factors, such as plant characteristics and soil properties. However, how these factors affect binding agents and soil aggregate stability along a climatic gradient remained unclear. We selected the Robinia pseudoacacia L. forests from semi-arid to semi-humid of the Loess Plateau, China to analyze the plant biomass, soil physical-chemical properties, SOC and GRSP distribution in different sized soil aggregates. We found that from semi-arid to semi-humid forests: (1) the proportion of macro-aggregates (>0.250 mm) significantly increased (P<0.05), whereas those of micro-aggregates (0.250-0.053 mm) and fine materials (<0.053 mm) decreased and soil aggregate stability was increased; (2) the contents of SOC and GRSP in macro-aggregates and micro-aggregates significantly increased, and those in fine materials decreased; (3) the contribution of SOC to soil aggregate stability was greater than those of total GRSP and easily extractable GRSP; (4) soil properties had greater influence on binding agents than plant biomass; and (5) soil aggregate stability was enhanced by increasing the contents of SOC and GRSP in macro-aggregates and soil property was the important part during this process. Climate change from semi-arid to semi-humid forests is important factor for soil structure formation because of its positive effect on soil aggregates.
Received: 27 March 2020
Published: 10 February 2021
JING Hang, MENG Min, WANG Guoliang, LIU Guobin. Aggregate binding agents improve soil aggregate stability in Robinia pseudoacacia forests along a climatic gradient on the Loess Plateau, China. Journal of Arid Land, 2021, 13(2): 165-174.
Fig. 1Location of the study sites. SM, Shenmu City; SD, Suide County; AS, Ansai District; CH, Chunhua County.
Latitude and longitude
Tree height (m)
Locust, yellow rose
Table 1 Information of the study sites
Water content (%)
AMF infection rate (%)
Above-ground biomass (kg)
Root biomass (kg)
Total biomass (kg)
Table 2 Soil property and R. pseudoacacia biomass of the study sites
Fig. 2Distribution (a) and stability (b) of soil aggregates at the study sites. Different lowercase letters indicate the significant differences among the study sites for each parameter at P<0.05 level. Different uppercase letters indicate significant difference among different sized aggregates at P<0.05 level. SM, Shenmu City; SD, Suide County; AS, Ansai District; CH, Chunhua County; MWD, mean weight diameter; GMD, geometric mean diameter; macro-aggregates, >0.250 mm; micro-aggregates, 0.250-0.053 mm; fine materials, <0.053 mm.
Fig. 3Distribution of easily extractable glomalin-related soil protein (EE-GRSP, a), total extractable glomalin-related soil protein (T-GRSP, b) and soil organic carbon (SOC, c) in aggregates. Different lowercase letters indicate significant differences among the study sites for each parameter at P<0.05 level. Different uppercase letters indicate significant differences among different sized aggregates at P<0.05 level. SM, Shenmu City; SD, Suide County; AS, Ansai District; CH, Chunhua County; macro-aggregates, >0.250 mm; micro-aggregates, 0.250-0.053 mm; fine materials, <0.053 mm.
Table 3 Bivariate correlation between mean weight diameter (MWD) and binding agents in soil aggregates
Fig. 4Redundancy analysis (RDA) of binding agents, soil property and R. pseudoacacia growth index. N, nitrogen; P, phosphorus; SOC, soil organic carbon; AMF, arbuscular mycorrhizal fungi; EE-GRSP and T-GRSP are easily extractable and total glomalin-related soil proteins, respectively; macro-aggregates, >0.250 mm; micro-aggregates, 0.250-0.053 mm; fine materials, <0.053 mm.
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