Jiayin Shaoa, Xiting Lia, Xiaojue Zhanga, Yuxin Wanga, Simone Raposo Cottab, Maurício Roberto Cherubinb, c, Lucas P. Canisaresb, Zhouping Shangguand, Weiming Yand, Lei Dengd, Yangquanwei Zhonga, e
a Shaanxi Key Laboratory of Qinling Ecological Intelligent Monitoring and Protection, School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, PR China
b Luiz de Queiroz College of Agriculture, University of São Paulo, Pádua Dias Av, 11, Piracicaba, SP 13418-900, Brazil
c Center for Carbon Research in Tropical Agriculture (CCARBON), University of São Paulo (USP), Piracicaba 13416-900, SP, Brazil
d State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, PR China
e Shenzhen Research Institute of Northwestern Polytechnical University, 518063, PR China
b Luiz de Queiroz College of Agriculture, University of São Paulo, Pádua Dias Av, 11, Piracicaba, SP 13418-900, Brazil
c Center for Carbon Research in Tropical Agriculture (CCARBON), University of São Paulo (USP), Piracicaba 13416-900, SP, Brazil
d State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, PR China
e Shenzhen Research Institute of Northwestern Polytechnical University, 518063, PR China
Highlights
- Long-term N fertilization significantly reduced SMF in the topsoil layer.
- Lower soil pH and C-acquiring enzyme activity decreased EMF.
- Abundant bacterial diversity plays a dominate role in SMF.
- Relationships between the microbial community and SMF were decoupled under N fertilization throughout the soil profile.
Abstract
Nitrogen (N) fertilization is widely implemented in agricultural ecosystems to increase crop yields. However, the long-term overuse of N poses a challenge to the sustainability of soil multifunctionality (SMF). Despite its importance, the impacts of long-term N application on soil properties, microbial communities, and SMF in the soil profile, as well as their relationships, remain poorly understood. Here, we investigated the enzyme stoichiometry, microbial communities, and SMF in a wheat field under continuous N application (0, 180, and 360 kg N·ha−1) for 19 years. Our findings revealed that long-term N fertilization reduced SMF by 32.95 % at a rate of 180 kg ha−1 and 57.13 % at a rate of 360 kg ha−1 in the topsoil layer (0–20 cm) (p < 0.05). However, no significant changes were observed in the subsoil layer (20–60 cm) among the treatments (p > 0.05). The decrease in SMF under N fertilization is primarily attributed to the inhibition of the activity of C-acquiring enzyme. This inhibition is driven by changes in abundant bacterial diversity, which are primarily affected by a decrease in the soil pH. Our results indicated that rare microbial taxa were more sensitive to N fertilization, while abundant microbial taxa played a crucial role in maintaining SMF. Additionally, the relationships between microbial communities and SMF throughout the soil profile were decoupled, primarily owing to the inconsistent responses of SMF and soil microbes to long-term N fertilization on the soil properties. Overall, these results indicate that long-term N fertilization significantly altered the soil properties, enzyme stoichiometry, and microbial communities; reduced SMF in the topsoil layer and weakened the link between microbial communities and SMF across the entire soil profile. Therefore, optimizing N fertilizer use is essential for reconciling food production with soil health and sustainable development.
Keywords
Soil microbes; Soil quality; Soil multifunctionality; Enzyme activity; Nitrogen fertilization
