Effect of climate change on nutrient cycling depending on plant community compositions
Dr. Muhammad Sana Ullah, Dr. Yakov Kuzyakov
Climate change in the 21st century will
impact many aspects of the human and natural world, including agriculture
sector. Under drought conditions,
soil or atmospheric water deficits cause reduced stomatal conductance and leaf
water potential, which restrict photosynthesis, leading to lower growth and
yield. Besides carbon (C) input, soil moisture is also an important factor
affecting ecosystem C exchange and soil organic matter decomposition. Taking
action through traditional breeding or biotechnology to develop crops that are
better adapted to future growing conditions will be aided by understanding the
mechanisms driving crop responses to climate change.
Although C allocation strongly influences plant and
soil processes, yet short-term C allocation dynamics in ecosystems and their
responses to environmental changes are still poorly understood. We will
investigate how drought stress may affect belowground C translocations,
microbial communities and nutrient cycles, depending on plant community
composition. To achieve these goals, we will conduct pot experiments under
controlled conditions and following techniques will be used to these scientific
questions:
·
Repeated
14CO2 pulse labelling of monocultures and mixture of
maize and sorghum along with natural 13C abundance.
·
Plant
physiological and biochemical parameters including stomatal conductance, transpiration
and photosynthetic rates.
·
14C incorporation in plant parts, soil, microbial
biomass, soil respiration (CO2 fluxes) and dissolved organic carbon
(DOC).
·
Priming
effects
·
Determination
of isotopes by using IRMS (13C and 15N) and
Scintillation (14C and 33P) techniques.
·
Isotopic
labelling with 15N and 33P and usage of Rb and Sr to
study plant-microbial competitions for major nutrients (N, P, K and Ca)
uptakes.
·
Soil
physical fractionation including density and particle-size fractionation.
·
Microbial
community composition and activities with determining total microbial biomass,
PLFA, Extra-cellular enzyme activities and soil zymography with 14C
imaging.