Response of plant-bacteria-soil system to phosphorus addition under simulated nitrogen deposition: evidence from a dryland ecosystem

AimsIncreased atmospheric nitrogen (N) deposition can alter plant growth and soil properties, thereby exerting many potential effects on soil microbial diversity and functionality. However, how phosphorus (P) addition regulates the responses of the plant-soil-microbe system to N deposition in dryland ecosystems remains unclear.MethodsTwo-year nutrient addition experiments, i.e., P addition rates ranging from 0 to 16 g P m(-2) yr(-1) combined with 5 g N m(-2) yr(-1), were performed to determine the effects on plant traits, soil properties, and bacterial communities in an alkaline desert steppe of Northwest China.ResultsUnder 5 g N center dot m(-2)center dot yr(-1), the low-dose of P addition rates (< 2 g m(-2) yr(-1)) can help maintain higher aboveground biomass and diversity. A C-3 herb (Artemisia scoparia) became progressively dominant with increasing P rates, accompanied by the loss of Fabaceae and Amaranthaceae species. Moreover, increased P rates had important implications for plant nutrient characteristics and soil properties under simulated N deposition. Notably, the alpha-diversity and structure of the soil bacterial community exhibited no significant response to nutrient addition, suggesting that the bacterial community was more resistant to nutrient addition than the plant community, which was relatively more sensitive. Furthermore, the bacterial community composition was jointly influenced by plant traits and soil properties.ConclusionsOur results suggest that dryland prokaryotic microbes are more resistant to P addition under simulated N deposition than plant communities.

Automated summary

The effects of phosphorus addition on plant growth and soil characteristics in response to nitrogen deposition in a dryland ecosystem were studied. The results showed that phosphorus addition had significant effects on plant traits and soil properties, but had no significant effect on soil bacterial communities.