Vegetation in karst terrain of southwestern China allocates more biomass to roots

Abstract

Abstract. In mountainous areas of southwestern China, especially Guizhou province, continuous, broadly distributed karst landscapes with harsh and fragile habitats often lead to land degradation. Research indicates that vegetation located in karst terrains has low aboveground biomass and land degradation that reduces vegetation biomass, but belowground biomass measurements are rarely reported. Using the soil pit method, we investigated the root biomass of karst vegetation in five land cover types: grassland, grassscrub tussock, thorn-scrub shrubland, scrub-tree forest, and mixed evergreen and deciduous forest in Maolan, southern Guizhou province, growing in two different soil-rich and rock-dominated habitats. The results show that roots in karst vegetation, especially the coarse roots, and roots in rocky habitats are mostly distributed in the topsoil layers (89 % on the surface up to 20 cm depth). The total root biomass in all habitats of all vegetation degradation periods is 18.77 Mg ha −1 , in which roots in rocky habitat have higher biomass than in earthy habitat, and coarse root biomass is larger than medium and fine root biomass. The root biomass of mixed evergreen and deciduous forest in karst habitat (35.83 Mg ha −1 ) is not greater than that of most typical, nonkarst evergreen broad-leaved forests in subtropical regions of China, but the ratio of root to aboveground biomass in karst forest (0.37) is significantly greater than the mean ratio (0.26 ± 0.07) of subtropical evergreen forests. Vegetation restoration in degraded karst terrain will significantly increase the belowground carbon stock, forming a potential regional carbon sink.

Effects of soil management techniques on soil water erosion in apricot orchards

“…The reason for the decrease in soil erosion rates as a consequence of vegetation recovery is because the vegetation reduces or avoids the rainfall erosivity (Cerdà, 1998;Keesstra, 2007;Ni et al, 2015;Taguas et al, 2015), improves soil properties and reduces runoff and soil losses. Keesstra et al (2009) found that vegetation recovery reduced sediment losses in Slovenia.…”

Biomass of karst evergreen and deciduous broad-leaved mixed forest in central Guizhou province, southwestern China: a comprehensive inventory of a 2 ha plot

“…The results showed that the AGB of this old-growth karst forest was significantly lower than that of other typical evergreen broad-leaved forests at similar latitudes (Yang and Cheng 1991;Zhu et al 1995;Yu et al 2002). Belowground biomass of different vegetation restoration stages at the same site has also been estimated using specific sampling method of digging four soil pits around an averaged sample tree (Luo et al 2010), as well as through normal soil pit method with 10 soil pits in a plot (Ni et al 2015). These sampling methods revealed higher BGB and root-shoot ratio of the karst forest than that of typical evergreen broad-leaved forests in subtropical China.…”

Groundcover influence on physical and chemical soil properties, runoff and nutrient loss and grape yield and quality in semiarid Mediterranean vineyards

“…However, the cover % of CB and CS were almost the same (Table 1.3). Therefore, the larger size of stems and root systems of the different species of spontaneous vegetation had a decisive effect on reducing the runoff and nitrate loss, as found by other authors recently (Ni et al, 2015;Ola et al, 2015;Shaw et al, 2016).…”