Nutrients addition regulates temperature sensitivity of maize straw mineralization

Purpose The study aimed to determine the interactive effect of temperature with nutrients on maize residues decomposition in soil. Materials and methods We conducted an incubation of 87 days by applying maize straw (delta C-13 value of -11.2 parts per thousand) to soil (delta C-13 value of -26.3 parts per thousand) with low (N-0), medium (N-M), and high (N-H) level of nutrients addition, at two temperature levels of 5 degrees C (T-L) and 25 degrees C (T-H). We measured the cumulative CO2-C efflux, residues decomposition, temperature sensitivity (Q(10)), and extracellular enzyme activities. Results and discussion Increased temperature significantly increased cumulative CO2 efflux and straw decomposition, with an enhanced rate of active (K-a) and slow (K-s) pools of soil and residues C. The mean values of Q(10) ranged from 1.4 to 1.6 for the total CO2 efflux and 1.4 to 1.7 for maize straw decomposition. The outcome might be due to temperature-dependent microbial activation at 25 degrees C. The activities of beta-glucosidase, alpha-glucosidase, cellobiohydrolase, and beta-xylosidase enzymes were positively correlated with cumulative CO2 emissions at 25 degrees C suggesting microbial regulation on SOM decomposition. We found a U-shaped pattern of nutrients regulation on the temperature sensitivity of maize straw decomposition, with the lowest Q10 under N-M. Conclusions Our findings suggest that nutrients regulated the temperature effects on residue C decomposition by adjusting microbial activity (extracellular enzyme activities). Consequently, it may lead to soil C sequestration under the current climate change scenario.

Automated summary

The study investigated the interactive effect of temperature with nutrients on maize residues decomposition in soil. The results showed that increased temperature enhanced CO2 efflux and straw decomposition, possibly due to temperature-dependent microbial activation. Nutrients were found to regulate the temperature sensitivity of residue C decomposition, potentially affecting soil C sequestration in the context of climate change.