Understanding the mechanisms for soil ecosystem services from 'perennialized' annual cropping systems

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Non-diversified crop rotations such as long-term monoculture of annual crops, frequent tillage, and reliance on fertilizer applications can result in the decline of soil quality, threatening the sustainability of food production systems. The implications of poor soil quality on long-term agricultural production are of local, national and global concern because of the increase in future food and water demands. Soil quality, defined as "the capacity of soil to function" is important to sustain crop productivity and the provision of soil ecosystem services (SES) such as greenhouse gas emission mitigation, support of microbial diversity, soil organic matter storage, and water filtration. The 'perennialization' of annual cropping systems is the integration of cover crops or intercrops such that the soil is never left fallow, in addition to diversifying annual crop rotations, a strategy that mimics natural ecosystems and is postulated to increase agricultural resilience to climate change, soil quality and provision of SES. The proposed research will investigate the mechanisms controlling soil quality and SES so the potential benefits and trade-offs of perennialized annual crop systems can be better understood. We propose to compare conventional and perennialized systems applied to corn, winter-wheat and soybean production using three experiments: 1) large high-precision weighing field lysimeters of 2 soil types and manipulated for warmer winter and summer drought (new infrastructure); 2) 35-yr long-term crop rotation; 3) field scale micrometeorological plots. We will use sophisticated techniques to characterize soil microbial communities, soil organic matter quality, greenhouse gas emissions, water budget, nitrate leaching and crop productivity (e.g. metagenomics, nuclear magnetic resonance spectroscopy, isotopic tracers, cavity ring-down spectroscopy), bringing together a unique team of experts in collaboration with partners in the agricultural sector and in government. Collected data will be used for validation of biogeochemical and hydrological models used at the national scale. Research outcomes will contribute to the economic and environmental viability of crop production through increased resilience to climate change and mitigation of trade-offs.