Soil quality includes the assessment of soil properties and its processes related to the ability of soil, to function effectively as a component of a healthy ecosystem. Many approaches have been used to select soil quality indicators, and develop a soil quality index (SQI).
Xishuangbanna is one of the hot spots with rich biodiversity and the second largest natural rubber planting base in China. However, no studies have reported on the relationship between plant diversity and soil quality under different seasons in the rubber plantations in Xishuangbanna.
In a study published in Ecological Indicators, researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences tried to analyze the response of soil properties as indicators of soil quality in different plant diversity and seasons.
The researchers collected soil samples during dry and rainy seasons at zero to ten cm depth from four sites (Bubeng, Jingtai, Nabanhe National Nature Reserve and XTBG) in Xishuangbanna, southwestern China.
They analyzed 16 soil physical, chemical and biological properties to choose the best representative indicators of soil quality by employing principal component analysis. They also selected total nitrogen, total sulphur, total organic carbon, the mass of dry root and soil fauna abundance (nematodes and arthropods) as the properties for the minimum data set.
Results showed that the SQI values differed significantly among different plant diversity at different seasons. SQI values showed that soil quality significantly decreased from high to low plant diversity in its corresponding seasons. The increase of plant diversity resulted in a positive effect on soil quality, and the highest values of SQI occurred in the dry season.
Total organic carbon, total nitrogen, arthropod abundance, the mass of dry root, nematode abundance and total sulphur were identified as key soil quality indicators. Among them, the total nitrogen and total organic carbon are the most important contributors to soil quality.
"Compared with monoculture rubber plantation, the natural understory vegetation as well as agro-forest management systems retain a higher concentration of soil properties. Therefore, we could not ignore them. Management of natural understory vegetation would be beneficial for the maintenance of soil quality in the rubber plantations of Xishuangbanna," said YANG Xiaodong of XTBG.
