Si Gao

Si Gao
California State University, Sacramento | CSUS · Department of Environmental Studies

PhD

About

36
Publications
9,740
Reads
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887
Citations
Introduction
I am a soil ecologist studying how the soil system serves as a natural solution to climate change. My work focuses on understanding how agricultural, forest, and rangeland management practices influence soil health and ecosystem functions. My research broadly includes biochar and soil nutrient cycling, soil organic matter persistence, greenhouse gas dynamics, fire, charcoal, and the impact of cultural fire stewardship practices on the soil system.
Additional affiliations
June 2021 - August 2022
University of California, Merced
Position
  • Postdoc Research Associate
June 2021 - June 2023
Oregon State University
Position
  • Affiliate Faculty
August 2020 - June 2021
Oregon State University
Position
  • Postdoc Research Associate
Education
August 2016 - May 2020
University of Montana
Field of study
  • Forest & Conservation Sciences
September 2014 - June 2016
University of Washington Seattle
Field of study
  • Environmental & Forest Sciences
August 2010 - June 2014
China Agricultural University
Field of study
  • Environmental Science

Publications

Publications (36)
Article
Biochar (a carbon-rich product from pyrolysis of organic materials) addition to agricultural soils has been proposed as a novel technology for enhancing soil C storage and fertility; however, few studies have evaluated the effects of biochar on nutrients from an integrated perspective. Previous studies have demonstrated that biochar has the potenti...
Article
Full-text available
Pyrogenic carbon (PyC) is a chemically stable form of carbon (C) generated during fire events and is one of the few legacies of fire recorded in soil; however, the significance of this material as a form of C storage in forest ecosystems has received only limited scientific attention, and currently relatively little is known regarding the quantity...
Chapter
Full-text available
This chapter serves as a review of the general mechanisms through which biochar influences nutrient availability to plants, and provides an evaluation of the effect biochar has on nutrient cycling and specific transformations for several key plant nutrients. We explore some of the knowns and unknowns regarding how biochar influences soil nutrient t...
Article
Full-text available
Dairy manure is one of the largest sources of methane (CH 4 ) emissions and air pollution from agriculture. In a previous study, we showed that composting dairy manure with biochar substantially reduces CH 4 emissions and could help the dairy industry meet climate goals. However, it remained unclear whether biochar could also mitigate the emission...
Article
Full-text available
Manure is a leading source of methane (CH 4), nitrous oxide (N 2 O), and ammonia (NH 3) emissions, and alternative manure management practices can help society meet climate goals and mitigate air pollution. Recent studies show that biochar-composting can substantially reduce emissions from manure. However, most studies test only one type of biochar...
Article
Full-text available
Forest soils of the Pacific Northwest contain immense amounts of carbon (C). Increasing acreage burned by severe wildfire in the western Oregon Cascades threatens belowground C stocks. The objective of this research was to quantify the changes in soil C stocks, nitrogen (N) stocks, and relevant chemical and physical parameters after a severe wildfi...
Article
Full-text available
Finding feasible solutions for sustainable food production is challenging. Here we try to understand the balance between crop productivity and ecological stewardship using agroecological‐based soil management strategies. We evaluated the potential of different organic materials such as dairy manure compost and different biochar manure co‐composts,...
Article
Full-text available
Organic amendments, such as compost and biochar, mitigate the environmental burdens associated with wasting organic resources and close nutrient loops by capturing, transforming, and resupplying nutrients to soils. While compost or biochar application to soil can enhance an agroecosystem's capacity to store carbon and produce food, there have been...
Article
Full-text available
Livestock are the largest source of anthropogenic methane (CH4) emissions, and in intensive dairy systems, manure management can contribute half of livestock CH4. Recent policies such as California's short-lived climate pollutant reduction law (SB 1383) and the Global Methane Pledge call for cuts to livestock CH4 by 2030. However, investments in CH...
Article
Few studies have been conducted to evaluate the use of wood biochar in temperate rangeland ecosystems and none have investigated the interactive influence of wood biochar and cattle trampling activity (associated with short-term rotational grazing) on soils and plants. We conducted a field study on a semi-natural pasture in western Montana, USA to...
Article
Full-text available
Climate changes are altering precipitation to more frequent extreme precipitation events that have strong impacts on the structure and functions of grassland ecosystems. We conducted a rain simulation experiment combined with in situ 15 N labeling of three nitrogen (N) forms (NO3−, NH4+, glycine) to investigate how the frequency of extreme precipit...
Article
During wildfire season in the western US, fire retardant chemicals are dropped from aircraft in an effort to control the spread of fire. Fire retardant dropped on sites that are not actively burning results in exceptionally high soil nitrogen (N) and phosphorus (P) “fertilization” effect on wildland soils impacting terrestrial and aquatic ecosystem...
Article
Full-text available
Responses of terrestrial ecosystems to decreased nitrogen (N) deposition has brought considerable attention. Soil organic carbon (SOC) turnover is an important parameter in the terrestrial ecosystem model and ecosystem management. However, how SOC turnover responds to decreased N deposition has not yet been evaluated. Here we addressed this issue b...
Chapter
The sustainability of the world's forest ecosystems is greatly dependent upon the health and function of soils, unfortunately, there is ambiguity in the term “soil health” and only limited understanding of biotic function in soils. This discord leaves land managers and policy makers to formulate decisions without adequate consideration of the soil...
Chapter
The sustainability of the world's forest ecosystems is greatly dependent upon the health and function of soils, unfortunately, there is ambiguity in the term “soil health” and only limited understanding of biotic function in soils. This discord leaves land managers and policy makers to formulate decisions without adequate consideration of the soil...
Chapter
There are currently relatively few studies on the use of biochar in organic farming systems, yet there is much that can be learned from historical use charcoal in agriculture and contemporary research in conventional agriculture. From the citrus fields of Japan to basket willow stands of north Great Britain to the famous Terra Preta soils of Amazon...
Conference Paper
Background/Question/Methods Biochar (a carbon-rich product from the pyrolysis of organic materials) addition to agricultural soils has been proposed as a novel technology for enhancing soil C storage and fertility, but few studies have evaluated effects on nutrients using a vertically integrated perspective. Previous studies have demonstrated that...
Article
Full-text available
Biochar (a carbon-rich product from pyrolysis of organic materials) additions to agricultural soils have been shown to often result in neutral to positive influences on soil properties and processes; however, the only a limited number of studies have been conducted on active organic farming systems and of those, none have used multivariate analytic...
Conference Paper
Background/Question/Methods With the need to develop sustainable agricultural systems, reduce soil degradation and fertility decline, biochar, a recalcitrant solid material that is generated from the pyrolysis of organic material under controlled conditions, has currently driven much interest to soil scientists. Biochar additions to agricultural s...
Article
Full-text available
Biochar, a solid carbon rich material and by-product of pyrolysis, has been identified as an amendment to improve soil fertility as well as sequester carbon (C). A growing number of studies have been conducted to test the effect of biochar in soil environment within the past ten years requiring frequent updated reviews and mini-reviews to summarize...
Conference Paper
Biochar additions to agricultural soil have been shown to result in many benefits; however, most studies have been conducted in greenhouse or laboratory trials with few being conducted on organic farms with on-site generated charcoal. Herein, we address this gap by conducting on-farm studies on the efficacy of locally produced biochar as a soil ame...

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