Effects of climate change factors on plant-microbial intereactions in Tibetan and Yellow Loess Plateau grasslands Research project
Hu, Shuijin
Description:During my sabbatical leave at Nanjing Agricultural University in 2014-2015, I helped design two long-term (planned for 10 years if funding is available) global change factor manipulation experiments, one each on the Tibetan Plateau Alpine (Maqu, Gansu Province) (33°59’N, 102°00’E, c. 3538 m a.s.l.) ) and Yellow Loess Plateau (Guyuan, Ningxia Hui Autonomous Region) (106°21′–106°27′E, 36°10′ – 36°17′N, altitude 1800–2000 m), northwest China. The two experiments have an identical design and treatments in field but they are under very different environmental conditions (alpine meadow vs. semi-arid grassland). Each field manipulation experiment involves three levels of precipitation (precipitation reduction by 30% (PR), ambient, precipitation increase by 30% (PI)), two levels of warming (ambient, warming) and two levels of N (ambient, 12 g m -2 yr -1 added N). Randomized block design was used with 4 replicates. In total, we had 48 (3 precipitation levels × 2 warming levels × 2 N addition levels × 4 blocks) plots at each site. The plots were 4 m × 4 m in size and 1.5 m away from each other in each block. The distance between each block was 5 m. We used open top chamber (OTCs) with a maximum basal diameter of 150 cm, following the International Tundra Experiment (ITEX) protocol (Papanikolaou et al. 2010; Waldrop & Firestone 2006), to increase air temperatures of the plots of the warming treatment. Nitrogen (206.9 g urea in total) was added as urea solution twice each year (half each in May and June). In each PR plot, we installed a rain shelter which was designed to prevent approximately 30% of precipitation in the plot. The rain shelter consisted of seven v-shaped transparent plexiglass and an iron hanger, which was 1 meter above the soil surface in the south side and 1.5 m on the north side. Intercepted rainfall in each PR plot was collected and then added into the nearest PI plot.
Each year, students, postdocs and young teachers from Nanjing Agric University stay on each site starting on early May to early October to maintain the field plots. It is really tough for them because of high elevation and poor field facilities (for example, no warm water on site but it is quite cold there).
Plant and soil samples have been collected or will be collected once or twice a year, pending on the manpower and funding availability.
I will mainly provide advice on sampling scheme, data analyses, and manuscript writing.
I strongly believe that it will be a significant contribution to the scientific community if we can maintain this long-term experiment. Because these sites locate in the region that is very sensitive to the ongoing climate change, we may obtain some unique results for the climate change community across the world. Some ecologists from US have visited these sites, including Dr. Scott Collins (Professor, U. of New Mexico, former president of Ecological Society of America), Dr. Valerie Eviner (Professor, UC Davis, former vice president of Ecological Society of America), Dr. Steven J. Hall at Iowa State and several professors from other universities in US.
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Dates:
05/01/2015 - 10/31/2024