Relationship Between Herbaceous Plant Diversity and Soil Factors at a Gully Head After Revegetation in Baicao Tableland

Abstract

[Objective] The changes in herbaceous plant diversity and the factors influencing those changes after revegetation at a gully head were studied in order to provide a relevant foundation for the assessment of the benefits of soil and water conservation in the loess tableland. [Methods] Herbaceous plant diversity at a gully head was measured and soil property indexes related to the topsoil (0—10 cm and 10—25 cm) were determined by selecting grassland gully heads with vegetation restoration periods of 5, 13, 18, and 22 years in the Baicao Tableland. Farmland was used as the control. [Results] The Patrick richness index initially increased with increasing number of vegetation restoration years, and then stabilized. The Shannon-Wiener index showed a continuously increasing trend, and the Shannon-Wiener index values in 18 and 22 years of vegetation restoration were greater than at 13 years of restoration. However, the differences were not significantly different. The Pielou evenness index exhibited a fluctuating trend of increasing, and then decreasing, then increasing again, reaching a maximum value (0.89) in 22 years of recovery. The soil bulk density in both the 0—10 cm and 10—25 cm layers reached a minimum value in 22 years of recovery, with significant decreases of 13.1% and 17.8%, respectively, compared with values observed for farmland (p<0.05). The soil organic matter content, water-stable aggregate content, mean weight diameter of aggregates, and saturated hydraulic conductivity in the 0—10 cm and 10—25 cm layers significantly increased with increasing number of vegetation restoration years, and soil factors between the two soil layers demonstrated significant differences at each restoration year. Correlation analysis indicated a negative correlation between herbaceous plant diversity indicators and soil bulk density, and a significant positive correlation (p<0.05) with soil organic matter content, water-stable aggregate content, mean weight diameter of aggregates, and saturated hydraulic conductivity. Redundancy analysis revealed that soil aggregate content was an important factor in explaining herbaceous plant diversity variation. [Conclusion] Vegetation restoration could significantly increase herbaceous plant diversity, and could play an important role in improving soil properties at a gully head in the loess tableland.

Keywords

• gully head
• herbaceous plant diversity
• soil property
• vegetation restoration
• baicao tableland
• loess plateau