Impacts of heat stress on soil-plant phosphorus dynamics and yield of chickpea (Cicer arietinum L.)

Evaluating the impacts of high temperature-mediated changes in soil-plant systems is crucial in sustaining the productivity of heat-sensitive crops like chickpea (Cicer arietinum L.). Currently, the impact of a high temperature environment on soil processes and crop nutrition, particularly phosphorus (P), remains uncertain in tropical alkaline soils. Therefore, an open-top chamber-based experiment with ambient temperature [a(Temp)] and elevated temperature [e(Temp)] (+2 degrees C over ambient) aimed to investigate the impacts of high temperature environment on plant physiology, soil plant P dynamics, and yield of chickpea in a moderately-alkaline Vertisol of sub-tropical climate. The e(Temp) reduced Olsen-P (available-P) and NaHCO3-Pi at the flowering stage by 12% and 32%, respectively, as compared to a(Temp) treatment. The e(Temp) treatment markedly reduced KMnO4-oxidizable carbon (-25% to 42%), but did not alter water-soluble carbon. Alkaline phosphatase and ss-glucosidase activities were reduced under the e(Temp) treatment, while acid phosphatase activity remained unchanged. The elevated temperature had a significant impact on chlorophyll-b content (+18%), stomatal conductance (+5%), transpiration rate (+8%), and photosynthetic rate (-22%). The e(Temp) treatment did not alter total P uptake rather altered its distribution in grain (-16%) and stover (+17%) parts, resulting in a lower internal P use efficiency (-12%) and P harvest index (+15%). The e(Temp) treatment caused 12% yield loss compared to a(Temp) treatment. Therefore, this is concluded that retardation in P-mineralization along with terminal heat stress could impair P nutrition, physiological activity, and yield of chickpea.