Crop diversity and human nutrition

Human health depends on the intake of a range of key nutrients. Yet food and agricultural policy has long been driven by caloric production (e.g. crop yield), which is only one dimension of the nutritional profile of crops. With Fabrice DeClerck, Ruth De Fries, Ro Remans, and Cheryl Palm we are studying how incorporating ecological diversity metrics into food systems can improve production targets for nutrition and minimize the amount of land needed for agriculture.

Microbial diversity and functional capacity on smallholder farms in Kenya

Increasing nutrient inputs to smallholder farms is an important strategy to increase crop yields. These inputs, however, may negatively impact soil biota and their ability to carry out ecological processes important to the sustainability of agricultural systems. In collaboration with Mark Bradford, Jack Gilbert, Shahid Naeem, Cheryl Palm, Joe Zhou, and others we are studying the response of soil microbial communities to mineral fertilization and agroforestry on smallholder farms in western Kenya to understand how efforts to increase yields impact the sustainability of agroecosystems.

Nutrient cycling and leaching in agroecosystems

Agriculture has drastically modified soil nutrient cycling through the addition of large amounts of chemical fertilizers. Where these extra nutrients go (to plants, the atomsphere, water systems, or attached to soil particles), and what factors determine their fate, is still a major topic of research. Kate Tully leads this work studying how nutrients on smallholder tropical farms that use different amounts and types of fertilizers (i.e. mineral vs organic) move through the soil profile.

Soil biodiversity and ecosystem functioning

It is well known that ecosystems with higher diversity of primary producers (e.g. plants) are more productive (e.g. have higher biomass). Whether diversity of soil organisms is similarly important is less known. This uncertainty is due to the fact that different soil organisms contribute to different ecosystem processes and can have both positive and negative effects. In collaboration with Mark Bradford, Shahid Naeem, and others we have conducted several studies to try to better understand when the biotic composition of soil influences rates of ecosystem processes.