Periodic Reporting for period 2 - RACe (The impact of climate change on the uptake of arsenic into rice)
Période du rapport: 2018-03-30 au 2019-03-29
The main results of the project were:
- The availability of arsenic in the soil increased due to future climatic conditions.
- Iron(III) and arsenate(V) reducing microbial communities are responsible for shifts in arsenic mobility in the soil.
- M206 grain yields decrease by 42% due to combined climate and soil arsenic stress compared to yields at today’s climate and arsenic soil concentrations.
- Future climatic conditions cause a nearly twofold increase of grain inorganic arsenic concentrations compared to today's climatic conditions.
- Soil arsenic is the stronger determinant of rice yield compared to climatic condition.
- A shift to future climatic conditions adversely affect grain arsenic levels even at low soil arsenic concentrations.
- Temperature increases soil arsenic bioavailability, elevated CO2 as well, though combined they increase arsenic bioavailability in between.
- Temperature decreases grain yields, elevated CO2 increases grain yield, jointly they decrease grain yield.
Part of the data was published (Muehe et al., Rice production threatened by coupled stresses of climate and soil arsenic, Nature Communications, 2019) and more manuscripts are in preparation. The data was also presented at several conferences, and invited scientific and general audience talks.
Furthermore, the current data presented two intriguing observations that led us to start two originally not planned projects. First, when tracking the dynamics of arsenic in the pore water, it was imminent that the first eight weeks of plant growth are important for later arsenic impacts on yield and quality. Thus, we constructed rhizobox experiments to better understand and spatially resolve what happens geochemically and microbially in the rhizospheres of rice plants exposed to different climates and arsenic conditions. This work has shown interesting results, indicating that the mineralogy of formed iron plaque around rice roots and the type of arsenic that is retain differs under different climatic conditions. We are currently writing up these results for publication.
Second, we observed differences in greenhouse gas emissions due to the presence of arsenic in the soil under different climatic conditions. Also here, we are currently preparing manuscripts.