Differences in soil properties and food web structure following 75 years of high-input wheat versus no-input harvested prairie meadows in Kansas

Background/Question/Methods

Soil ecosystem properties and processes which simultaneously maintain native fertility and sustain plant yields are of principal interest in sustainable agriculture. Native prairies in Kansas are relevant in this context, as they have been annually hayed with no fertilization or detectable decline in yield or soil fertility. In contrast, intensive wheat production has resulted in significant reductions in soil fertility and now requires intensive inputs to maintain yield. The objective of this study was to identify major differences in soil bacterial and nematode communities between these prairies and adjacent annual wheat fields in order to gain insight into possible mechanisms driving nutrient and energy efficiencies in prairies. 
Results/Conclusions

T-RFLP analyses and microscopic identification revealed major differences between bacterial and nematode communities between these two systems. Nematode communities indicated greater fungal decomposition pathways, less plant parasitic nematodes, and greater food web complexity and stability than found in annual wheat fields. In addition, free-living, nitrogen fixing bacterial community structure was strongly shaped by differences between prairies and annual wheat sites. These collective differences in soil biology suggest greater N mineralization rates and synchrony with plant nutrient demand in hayed prairie sites and may help explain the greater efficiencies observed in these systems.