Molecular and Dual-Isotopic Profiling of the Microbial Controls on Nitrogen Leaching in Agricultural Soils under Managed Aquifer Recharge.

Nitrate (NO) leaching is a serious health and ecological concern in global agroecosystems, particularly those under the application of agricultural-managed aquifer recharge (Ag-MAR); however, there is an absence of information on microbial controls affecting NO leaching outcomes. We combine natural dual isotopes of NO (N/N and O/O) with metagenomics, quantitative polymerase chain reaction (PCR), and a threshold indicator taxa analysis (TITAN) to investigate the activities, taxon profiles, and environmental controls of soil microbiome associated with NO leaching at different depths from Californian vineyards under Ag-MAR application. The isotopic signatures demonstrated a significant priming effect ( < 0.

A comprehensive resilience assessment of Mexican tree species and their relationship with drought events over the last century.

The resilience of forests to drought events has become a major natural resource sustainability concern, especially in response to climate change. Yet, little is known about the legacy effects of repeated droughts, and tree species ability to respond across environmental gradients. In this study, we used a tree-ring database (121 sites) to evaluate the overall resilience of tree species to drought events in the last century.

Nitrogen fate during agricultural managed aquifer recharge: Linking plant response, hydrologic, and geochemical processes.

Agricultural managed aquifer recharge (Ag-MAR, on-farm recharge), where farmland is flooded with excess surface water to intentionally recharge groundwater, has received increasing attention by policy makers and researchers in recent years. However, there remain concerns about the potential for Ag-MAR to exacerbate nitrate (NO) contamination of groundwater, and additional risks, such as greenhouse gas emissions and crop tolerance to prolonged flooding. Here, we conducted a large-scale, replicated winter groundwater recharge experiment to quantify the effect of Ag-MAR on soil N biogeochemical transformations, potential NO leaching to groundwater, soil physico-chemical conditions, and crop yield.

Reducing greenhouse gas emissions and stabilizing nutrients from dairy manure using chemical coagulation.

Two primary concerns of dairies that store manure wastewater in anaerobic ponds are greenhouse gas (GHG) emissions and unpredictable nutrient availability after applying it to forage crops. Solid-liquid separation of dairy manure wastewater with chemical coagulants significantly reduces the fraction of organic matter stored in anaerobic conditions. However, the effects of coagulants on methane emissions from ponds and nutrient availability following field application are not well understood.

Global soil-derived ammonia emissions from agricultural nitrogen fertilizer application: A refinement based on regional and crop-specific emission factors.

Ammonia (NH ) emissions from fertilized soils to the atmosphere and the subsequent deposition to land surface exert adverse effects on biogeochemical nitrogen (N) cycling. The region- and crop-specific emission factors (EFs) of N fertilizer for NH are poorly developed and therefore the global estimate of soil NH emissions from agricultural N fertilizer application is constrained. Here we quantified the region- and crop-specific NH EFs of N fertilizer by compiling data from 324 worldwide manipulative studies and focused to map the global soil NH emissions from agricultural N fertilizer application.