A5004573311- Soil Carbon and Nitrogen Dynamics
- Soil and Water Nutrient Dynamics
- Plant Water Relations and Carbon Dynamics
- Peatlands and Wetlands Ecology
- Soil and Unsaturated Flow
- Plant responses to elevated CO2
- Soil erosion and sediment transport
- Soil Management and Crop Yield
- Tree-ring climate responses
- Clay minerals and soil interactions
- Crop Yield and Soil Fertility
- Microbial Community Ecology and Physiology
- Forest ecology and management
- Groundwater and Isotope Geochemistry
- Iron oxide chemistry and applications
- Hydrology and Watershed Management Studies
- Isotope Analysis in Ecology
- Soil Geostatistics and Mapping
- Fire effects on ecosystems
- Plant nutrient uptake and metabolism
- Atmospheric and Environmental Gas Dynamics
- Ecology and Vegetation Dynamics Studies
- Composting and Vermicomposting Techniques
- Agriculture, Soil, Plant Science
- Legume Nitrogen Fixing Symbiosis
University of California, Davis
2016-2025
University of California Division of Agriculture and Natural Resources
2008-2024
Northeast Institute of Geography and Agroecology
2019-2020
Chinese Academy of Sciences
2019-2020
University of California System
2005-2018
Thuyloi University
2008-2013
Michigan State University
1996-2013
Plant (United States)
2008
Iowa State University
2006
Corvallis Environmental Center
2003
The use of 13 C natural abundance (δ C) to follow input soil has gained widespread acceptance. However, inorganic present in the as carbonates will interfere with measurement organic unless removed or excluded from measurement. We report a simple and convenient HCl‐fumigation method remove soil. Soil samples are weighed Ag‐foil capsules, arranged on microtiter plate, wetted water approximately field capacity, placed desiccator containing beaker concentrated (12 M ) HCl. released CO 2 by acid...
Abstract A spectrophotometric procedure for determination of nitrate in water, soil extracts, and a variety other sample types is described using one reagent solution which easily prepared stored. Sample equipment requirements are minimal. Reduced chemical hazard, simplicity, versatility represent improvements over existing methods. Limit detection 0.01 µg N mL−1 (0.72 μM ) or less, depending on the matrix.
The continuous increase of nitrous oxide (N 2 O) abundance in the atmosphere is a global concern. Multiple pathways N O production occur soil, but their significance and dependence on oxygen (O ) availability nitrogen (N) fertilizer source are poorly understood. We examined nitric (NO) under 21%, 3%, 1%, 0.5%, 0% (vol/vol) concentrations following urea or ammonium sulfate [(NH 4 SO ] additions loam, clay sandy loam soils that also contained ample nitrate. contribution ammonia (NH 3 oxidation...
Abstract Soil chemical properties during the transition from conventional to organic and low‐input farming practices were studied over 8 yr in California's Sacramento Valley document changes soil fertility status nutrient storage. Four systems differing crop rotation external inputs established on land previously managed conventionally. Fertility system depended animal manure applications winter cover crops; two received synthetic fertilizer inputs; used crops first 3 for remaining 5 yr. At...
Climate-smart agriculture (CSA) addresses the challenge of meeting growing demand for food, fibre and fuel, despite changing climate fewer opportunities agricultural expansion on additional lands. CSA focuses contributing to economic development, poverty reduction food security; maintaining enhancing productivity resilience natural ecosystem functions, thus building capital; reducing trade-offs involved in these goals. Current gaps knowledge, work within CSA, agendas interdisciplinary...
Core Ideas POXC and mineralizable C were evaluated across diverse agroecosystems. The two are related but differentially influenced by management practices. better reflected SOM stabilizing Mineralizable mineralizing Both predicted agronomic performance than other soil fractions. Permanganate‐oxidizable (POXC) (as determined short‐term aerobic incubation of rewetted soil) measures active organic matter that may provide early indication stabilization mineralization processes. To date, the...
Abstract Breeding high‐yielding rice cultivars through increasing biomass is a key strategy to meet rising global food demands. Yet, growth can stimulate methane ( CH 4 ) emissions, exacerbating climate change, as cultivation major source of this powerful greenhouse gas. Here, we show in series experiments that actually reduce emissions from typical paddy soils. Averaged across 33 cultivars, increase 10% resulted 10.3% decrease soil with high carbon (C) content. Compared low‐yielding...
Abstract Ammonia (NH 3 ) emissions from fertilized soils to the atmosphere and subsequent deposition land surface exert adverse effects on biogeochemical nitrogen (N) cycling. The region‐ crop‐specific emission factors (EFs) of N fertilizer for NH are poorly developed therefore global estimate soil agricultural application is constrained. Here we quantified EFs by compiling data 324 worldwide manipulative studies focused map application. Globally, averaged 12.56% 14.12% synthetic manure,...
The high‐value, large‐scale crop production systems in the San Joaquin Valley (SJV) of California typically entail intensive tillage and large fertilizer water inputs but few C additions to soil. Such practices often contribute a decline soil quality. Our objective for this participatory study was examine effects supplemental management (SCMPs) on various quality indicators. To increase farmer participation, we conducted farms using variety SCMPs, including cover crops, compost manure...
The high-value, large-scale crop production systems in the San Joaquin Valley (SJV) of California typically entail intensive tillage and large fertilizer water inputs but few C additions to soil. Such practices often contribute a decline soil quality. Our objective for this participatory study was examine effects supplemental management (SCMPs) on various quality indicators. To increase farmer participation, we conducted farms using variety SCMPs, including cover crops, compost manure...
Increased use of heavy equipment and more frequent entry into forest stands has increased the potential for soil compaction decreased productivity. We examined tree growth relationships on three California soils contrasting textures (clayey, loamy, sandy loam) plots from which organic horizon had been removed. Compacted noncompacted treatments were compared. Changes in bulk density (D b ), strength, total porosity, measured during growing season, greatest 15‐ to 30‐cm depth at all sites....
Abstract Coupled climate–ecosystem models predict significant alteration of temperate forest biome distribution in response to climate warming. Temperate biomes contain approximately 10% global soil carbon (C) stocks and therefore any change their may have impacts on terrestrial C budgets. Using the Sierra Nevada as a model system for soils, we examined effects temperature mineralogy mineralization. We incubated soils from three conifer dominated by ponderosa pine (PP), white fir (WF), red...