Effects of nanocarbon and nano-calcium carbonate on soil enzyme activities and soil microbial community in wheat (Triticum aestivum L.) rhizosphere soil

Background: Nanofertilisers can enhance the efficiency of nutrient utilization in crop production. Nevertheless, it is unclear how soil microbial and enzyme activities are affected by the application of nanofertilisers to wheat inter-root soil.Aims: The study aims to investigate the influences of nanocarbon (NC) and nano-calcium carbonate (NCC) on soil enzyme activities and microbial community in the open field setting.Methods: The effects of nanofertilisers on soil wheat rhizosphere soil were studied through the evaluation of soil microbial quantity, enzyme activity, and microbial diversity.Results: The findings revealed that the combined utilization of nanofertilizers and compound fertilizers (CF) led to an augmentation in the diversity of the soil microbial community. When comparing the effects of 100% composite nanofertilizers (100% CF + 50% NC + 50% NCC) with the control (CK) (100% CF), it was observed that the activities of urease (EC 3.5.1.5), catalase (EC 1.11.1.6), alkaline phosphatase (EC 3.1.3.1), sucrase (EC.3.2.1.26), as well as the number of fungi, actinomycetes, and bacteria, increased by 22.4%, 7.7%, 17.8%, 9.3%, 35.9%, 27.7%, and 26.0%, respectively. Similarly, the employment of 70% composite nanofertilizers (70% CF + 35% NC + 35% NCC) also resulted in an enhancement of these aforementioned indicators. The magnitude of increase over the 100% CF was 19.0%, 6.6%, 13.6%, 6.2%, 26.8%, 21.3%, and 23.5%, respectively. Notably, there was no significant difference observed between 100% CF + 50% NC + 50 % NCC and 70% CF + 35% NC + 35% NCC within the 0-35 d after anthesis. Furthermore, both 100% CF + 50% NC + 50% NCC and 70% CF + 35% NC + 35% NCC contributed to an improvement in the species uniformity and operational taxonomic unit abundance of wheat rhizosphere microorganisms, while also increasing the abundance of Proteobacteria and Actinobacteria compared to the CK. The relative abundance of Bacteroidetes and Actinobacteria was found to be elevated in the nanomaterials-treated groups, both at 0-7 d and 14-21 d after anthesis, and positively correlated with soil enzyme activities and soil microbial populations.Conclusions: These results indicate that the application of composite nanofertilizers can enhance the soil microenvironment in wheat fields, particularly under reduced fertilization conditions.