Agroecology research in the LTER-Row Crop at KBS focuses on understanding the principles of resilient cropping system design and biologically-based management. This includes investigating the multi-functional role of accessory crops such as cover crops in mediating nutrient efficiency, soil function and healthy crop roots. A particular area of interest in Sieglinde Snapp’s lab is the feedback loops in nitrogen and phosphorus availability, mediated by plant species composition, associated microbes and enhanced duration of plant growth over the year.
LTER and Living Field Laboratory Long-term Trials at KBS
- Plant and soil community feedback mechanisms at different time scales; and
- Plant functional traits and assemblages that are drivers in nutrient and water cycling efficiency, and system resilience.
Predicting nutrient availability and tradeoffs between mineralization and assimilation processes are important questions addressed through LTER research collaborations and working with farmers in organic and low input production systems on coarse soils.
The LTER-row crop main plot experiments are producing findings of relevance to cereal based agroecosystems in Alfisols around the globe. Improved, nutrient efficient management principles apply to cereal-legume rotation sequences such as corn-soybean-wheat and sorghum-peanut ystems in the temperate Great Lakes Upper Midwest and semi-arid to sub-humid tropics of West and Southern Africa. Enhanced nutrient use efficiency through diversification with legumes and enhanced duration of living cover has been shown to improve fertilizer efficiency, reduced variability in productivity over the long-term and enhanced labile soil C, N and organic P pools. The findings are critical to designing cropping systems that are appropriate to limited resource farmers.
Understanding the ecosystem traits that build resilience in these cropping systems will improve our ability to ‘build in’ adaptation to biotic and abiotic stress. This is of central importance to farmers facing increasing risks from the threat of epidemics, and variable weather associated with climate change. Upper Midwest farmers and land managers throughout North America require improved understanding of how to enhance system properties of resilience and positive feedbacks, to reduce negative environmental impacts while maintaining economically viable options for farming and related livelihoods. Smallholder farmers on sandy soils at the Sahel margins and Lower Rift Valley in Sub-Saharan Africa have even more limited options, but are starting to use the same principles of replacing large doses of external inputs with integrated nutrient and crop management strategies, based on biological principles to improve efficiency and cropping system resilience.