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| DOI：10.13522/j.cnki.ggps.2019137 |
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| Vegetation Types Affect Responsive Change in Soil Moisture to Rainfall in under Karst Rocky Desertification Control Areas |
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JING Jiansheng, LIU Ziqi*, LI Yuan, WANG Jin, LUO Ding, CAI Lulu
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School of Karst Science, Guizhou Normal University/State Engineering Technology Institute for Karst Desertification Control, Guiyang 550001, China
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| Abstract: |
| 【Objective】The uniqueness in geomorphology and vegetation coverage in karst rocky desertification control areas makes water infiltration and plant growth in them differ from those in other areas. As plant growth relies on soil water in their root zone, it is important to understand how vegetation types affect the responsive change in root-zone soil moisture to rainfall. The purpose of this paper is to address this.【Method】We studied Zanthoxylum bungeanum land, Lonicera japonica land, Hylocereus undulates growing in land and wasteland. On each site, we measured rainfall and soil moisture content in 0~10 cm and 10~25 cm soil layers. These data were used to calculate soil moisture storage and its lagging response to rainfall, as well as effective recharge rate and recharge efficiency.【Result】①The responsive change in soil moisture content in the four vegetation types to rainfall was consistent, peaking in June, August and September. The soil moisture in top soil under the four vegetations was ranked in Hylocereus undulatus land > Hylocereus undulatus wasteland > Lonicera japonica land > Zanthoxylum bungeanum land. The variation coefficient of the soil moisture content was the least in Hylocereus undulatus land and the highest in Hylocereus undulatus wasteland. ②The responsive change in soil moisture content to sprinkle irrigation was not significant between the four vegetations, increasing only in the Hylocereus undulatus land by 11.97%. With the increase in rainfall, the change in soil moisture content was the least in Hylocereus undulatus land varying from 7.89% to 17.94%, followed by Lonicera japonica land varying from 0 to 45.09%, Hylocereus undulatus wasteland varying from 0 to 59.86%, and Zanthoxylum bungeanum land varying from 0 to 126.95%. The increasing rate in soil moisture content in Hylocereus undulatus land after heavy rain events was the least, while the increasing rate in other three treatments after light rainfalls and large torrential rainfalls was small. ③The response of soil moisture to rainfall varied significantly between vegetation types, faster to heavy rainfall than to small and moderate rainfall. The response of water in 0~10 cm soil layer was faster than that in 10~25 cm soil layer. The average lag in soil moisture response was 0.3 h in Hylocereus undulatus wasteland, 0.5 h in Hylocereus undulatus land, 0.9 h in Zanthoxylum bungeanum land, and 3.0 h in Lonicera japonica land. The order of the effective recharge efficiency was Hylocereus undulatus land (64.87%) > Hylocereus undulatus wasteland (38.16%) > Zanthoxylum bungeanum land (31.94%) > Lonicera japonica land (29.23%). 【Conclusion】Reducing irrigation and increasing vegetation coverage in Hylocereus undulatus land in wet season can reduce soil erosion, while in Lonicera japonica and Zanthoxylum bungeanum lands, efforts should focus on improving use efficiency of rainfall and water infiltration during dry seasons. |
| Key words: rocky desertification; vegetation types; soil moisture; rainfall |
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