Biogenic VOCs emission inventory development of temperate grassland vegetation in Xilin River Basin, Inner Mongolia, China

Given the key role of biogenic volatile organic compounds(VOCs) to tropospheric chemistry and regional air quality, it is important to generate accurate VOCs emission inventories. However, only a less fraction of plant species, in temperate grassland of Inner Mongolia, has been characterized by quantitative measurements. A taxonomic methodology, which assigns VOCs measurements to unmeasured species, is an applicable and inexpensive alternation for extensive VOCs emission survey, although data are needed for additional plant families and genera to further validate the taxonomic approach in grassland vegetation. In this experiment, VOCs emission rates of 178 plant species were measured with a portable photoionization detector(PID). The results showed the most of genera and some families have consistent feature of their VOCs emission, especially for isoprene, and provide the basic premise of taxonomic methodology to develop VOCs emission inventories for temperate grassland. Then, the taxonomic methodology was introduced into assigning emission rate to other 96 species, which no measured emission rates available here. A systematical emission inventory of temperate grassland vegetation in Inner Mongolia was provided and further evidence that taxonomy relationship can serve as a useful guide for generalizing the emissions behavior of many, but not all, plant families and genera to grassland vegetation.

Response of Grassland Vegetation to Air Temperature and Precipitation in Minqin Desert Region

[ Objective] This paper aims to analyze response characteristics of desert grassland vegetation to climate change. [ Method] The responses of grassland vegetation in desert region to air temperature/precipitation changes were analyzed by phenological observations since 1974, observation data conceming vegetation samples and meteorological data during the same period. The changing trend significance was denoted by linear trend line and its regression significance. The interrelation between the two variables was indicated by correlation coefficients. Data were analyzed by the software SPSS 13.0. [Result] （1） The rising rate of annual average temperature in the Minqin desert area since 1961 was greater than both the global level and Ghina＇s level over the past century. （2） Desert plants＇ response to temperature changes were mainly displayed as the advance of spring phenology, the delay of autumn phenology and the extension of growing duration. Plants＇ main response to precipitation changes was that vegetation coverage and pure coverage were decreasing along with precipitation reducing. （3） Both the vegetation coverage and pure coverage mainly had a positive correlation with the annual precipitation. Plant density mostly had a positive correlation with the precipitation in September. （4） The impact of rising temperature on plant phenology in spring was greater than that in autumn. [ Conclusion] The effects of temperature changes on desert grassland plants were the advance of spring phenology, the delay of autumn phenology, the extension of growing season and longer plant growing period than that in other reports. The responses of desert grassland vegetation to precipitation changes were that both vegetation coverage and pure coverage were decreasing along with precipitation reducing, and plant density fluctuated along with precipitation change.

Application of Self-pressure Sprinkler Irrigation Technology to Grassland Vegetation Restoration in Alpine Arid Areas

To study the application of self-pressure sprinkler irrigation technology to vegetation restoration of grassland in alpine arid areas,three treatments including fenced grassland(FG),fencedirrigated grassland(FA),and free grazing grassland(CK) were compared in respect of primary productivity.The results showed that the community coverage of FA was only 35.96% higher than that of FG and 152.69% higher than that of CK;the plant height of FA was only 76.71% higher than that of FG and 155.77% higher than that of CK;the productivity of the community in FA was only 24.10% higher than that of FG and 110.00% higher than that of CK.It indicates that the self-pressure sprinkler irrigation technology has certain demonstration and promotion potential in vegetation restoration of grassland in alpine regions and can provide a new way for the sustainable development of grassland animal husbandry in Tibet.

Variations in the Volatile Organic Compound Emission Potential of Plant Functional Groups in the Temperate Grassland Vegetation of Inner Mongolia, China

Abstract: The biogenic volatile organic compounds (VOC) emitted by the vegetation of a terrestrial ecosystem play a key role in both regional air quality and tropospheric chemistry. To describe the general emission properties of VOC of different plant functional groups (PFG) in a typical temperate grassland in Inner Mongolia, China, we randomly selected 175 plant species and measured the quantities of isoprene and monoterpene in situ. Results showed that most plants had low VOC emission potential at the species level, especially for some dominant plants, such as Leymus chinensis Tzvel., Stipa grandis Smirn., and Agropyron cristatum Gaertn. At the PFG level, the lowest VOC emission potential was found for perennial rhizome grasses, a major PFG in a typical temperate grassland ecosystem. The effects of overgrazing and subsequent vegetation succession on the emission of VOC by different plant life form functional groups (PLFG) were also discussed.