Variation of soil physicochemical properties of different vegetation restoration types on subtropical karst area in southern China.

To carry out differentiated ecological restoration activities and formulate appropriate environmental conservation strategies for karst regions, it is essential to investigate the impact of ecological restoration and forest management strategy differences on soil properties. The karst region in Xiangxi, Hunan province, China was selected as the study site. Here, we determined soil physical and chemical differences in soil profiles of karst areas with ecological restoration activities. The results showed that (1) the soil properties showed a significant difference between the restoration vegetation and uncultivated land, especially in soil physical properties. The soil moisture conversion coefficient (83.0%) and soil bulk density (1.37g/cm3) of Liriodendron chinense (Hemsl.) Sarg reached the highest value among 12 vegetations. 2) The topsoil was more sensitive to ecological restoration. Soil physical properties in the topsoil samples from the forest management areas were significantly higher than uncultivated lands (P < 0.05). (3) Redundancy analysis showed that the soil chemical content differed significantly among the types of forest vegetation restoration and different soil layers. Among the nutrients analysis, Mg, Zn and K were the main factors affecting soil properties in the rocky desertification areas. Therefore, our results recommend planting the broadleaved deciduous forest as the preferred forest among three different forest types to enhance soil fertility and water conservation functions, especially in subtropical karst areas ecosystems, which provided for making scientific forest restoration management in the karst region.

[Effect of organs biomass by drought stress on the leaf growing stage of Angelica dahurica var. formosana].

OBJECTIVE: To study the effect of natural drought stress conditions on Angelica dahurica var. formnosana vegetative organs biomass accumulation and allocation in leaf growing season. To discuss the changing law of Angelica dahurica var. formosana vegetative organs biomass in different drought stress conditions. METHODS: Measured Angelica dahurica var. formnosana leaf and leafstalk's biomass, all aboveground biomass and the ratio of root biomass, leaf biomass, root/shoot ratio etc. in the growing season under the natural drought stress condition. RESULTS: Slight drought stress condition was good for organs' biomass accumulation, medium and serious drought stress conditions were bad for organs biomass accumulation. Slight and medium drought stress conditions were good for biomass transit to the root in the leaf growing season and serious drought stress condition was not good for that. CONCLUSION: Suitable drought stress can improve the root biomass ratio in Angelica dahurica var. formosana leaf growing season and get a better yield.