description
- Modern agriculture is subject to increasing regulatory pressure on the use of fertilisers and crop protection products, and economic pressure to maintain crop yields. In addition, models predict significant changes in the pattern of rainfall in the UK, including a reduction in summer precipitation of up to 40%, and an increase the number of extreme rainfall events. It is critical that we understand the mechanisms underpinning the agricultural ecosystem response to this change in rainfall pattern, and the effect this has on water stress in crops, and ultimately on crop yield. This project makes a novel link between two research leaders, one an expert in the analysis of community ecology of soil microbes using cutting edge molecular techniques, and the other a leader in the biogeochemistry of soil water and nutrient cycling. This expertise will be brought together to gain a timely understanding of the interactions between soil biodiversity and chemistry, change in precipitation patterns and crop yield. Objectives: The overarching aim is to determine how microbial diversity interacts with precipitation patterns of drought and re-wetting to influence water stress in wheat crops and nitrate retention in a nitrate vulnerable zone (NVZ). Recent evidence suggests that prolonged drought with extreme rainfall events has a profound effect on crop water relations. The abundance of prokaryote communities and arbuscular mycorrhizal fungi may increase nitrate recycling within soils, but the interaction between these processes, water stress in crops, and precipitation patterns predicted under future climate change scenarios are not known. The hypotheses tested will be: 1) The diversity and abundance of microbes are key drivers of nitrate retention dynamics in agricultural settings. 2) Transient anoxia driven by fewer, but more intense, rainfall events will alter the balance among microbial processes, notably nitrification and denitrification, and thus overall nitrate leaching 3) The abundance of arbuscular mycorrhizal fungi, and consequent interaction with nitrogen cycling prokaryotes, will further alter nitrogen cycling dynamics, and will be associated with lower nitrate leaching