Temperature dependent effects of Terrenova amendment on soil microbial properties and plant biochemical and physiological responses

Abstract Understanding how temperature fluctuations and soil amendments such as Terrenova affect soil microbial activity and plant health is crucial in context of climate change, yet their interaction remain poorly understood. This study aims to investigate (i) the effects of temperature, and (ii) the interactive effects of temperature with Terrenova on soil microbial properties and plant growth, including biochemical and physiological responses. A completely randomized design with 4-treatments were used: H (High temperature), L (Low temperature), H + t (High temperature with Terrenova), and L + t (Low temperature with Terrenova), each with three (n = 3) replications. Our findings showed that higher temperature reduced microbial diversity (e.g., SDI) and soil respiration, while lower temperature had the opposite effects. In plants, lower temperature activated stress-responses with increased nitrate reductase activity, soluble proteins and polyphenols, whereas higher temperature promoted biomass accumulation. Physiologically, higher temperature enhanced stomatal conductance, intercellular CO2 concentration and transpiration, reflecting heat-stress response. Terrenova improved microbial diversity at higher temperature and reduced soil respiration under both conditions. Its effects in plant properties were temperature-dependent, boosting soluble proteins at higher temperature while reducing proteins and polyphenols at lower temperature. Additionally, Terrenova enhanced gas exchange and water regulation under both temperatures, although it reduced chlorophyll concentration at higher temperature, suggesting an energy allocation trade-off. Notably, it boosted photosynthetic capacity under both temperatures, contributing to improved plant productivity. In conclusion, soil amendments like Terrenova could play a significant role in mitigating temperature-related stresses on soil microbial properties and plant productivity, contributing to more resilient agroecosystems under climate variability.