Keith Paustian

Keith Paustian
Colorado State University | CSU · Natural Resource Ecology Laboratory

About

365
Publications
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Citations

Publications

Publications (365)
Article
Improved agricultural soil management can facilitate the removal of carbon dioxide from the atmosphere to help keep planetary warming at or below 2 °C as outlined in the Paris Agreement. The application of compost to agricultural soils increases soil carbon by directly fertilizing the soil with carbon (no net carbon dioxide removal), and by stimula...
Article
Full-text available
Meeting end-of-century global warming targets requires aggressive action on multiple fronts. Recent reports note the futility of addressing mitigation goals without fully engaging the agricultural sector, yet no available assessments combine both nature-based solutions (reforestation, grassland and wetland protection, and agricultural practice chan...
Article
Increasing demand for land-based climate mitigation requires more efficient management of agricultural landscapes for competing objectives. Here we develop methods for assessing trade-offs and synergies between intensification and carbon-sequestering conservation measures in annual crop production landscapes using the DayCent ecosystem model and th...
Article
Full-text available
Sustainable aviation fuel (SAF) production from lipids is a technologically mature approach for replacing conventional fossil fuel use in the aviation sector, and there is increasing demand for such feedstocks. The oilseed Brassica carinata (known as Ethiopian mustard or simply carinata) is a promising SAF feedstock that can be grown as a supplemen...
Article
Considering the importance of soil organic carbon (SOC) and the scarcity of data on how soil management influences its storage in the region, this study assessed the long-term impact of different soil management systems on SOC in southern Ethiopia using the DAYCENT model. The conservation management systems considered were minimum tillage, crop res...
Article
CONTEXT Cover crops deliver numerous ecosystem services including the capacity to sequester and store atmospheric CO2 offering promise as a natural climate solution. Farm system models must be able to accurately represent cover crop systems and estimate the associated net greenhouse gas emissions from this practice across agricultural contexts. OB...
Article
Full-text available
For decades, predominant soil biogeochemical models have used conceptual soil organic matter (SOM) pools and only simulated them to a shallow depth in soil. Efforts to overcome these limitations have prompted the development of the new generation SOM models, including MEMS 1.0, which represents measurable biophysical SOM fractions, over the entire...
Article
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Nitrogen (N) loss through ammonia \(({\mathrm{NH}}_{3})\) volatilization in agricultural soils is a significant source of atmospheric \({\mathrm{NH}}_{3}\), contributing to low N use efficiency in crops, risk to human health, environmental pollution, and is an indirect source of nitrous oxide \(({\mathrm{N}}_{2}\mathrm{O})\) emissions. Our objectiv...
Article
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Globally, poorly managed pasture can contribute to increasing greenhouse gas (GHG) emissions. In Brazil, sustainable management systems are being proposed to reduce carbon dioxide (CO 2) emissions and increase the soil C stock under degraded pasture. However, despite the potential benefits in the adoption of sustainable management systems, few stud...
Preprint
Full-text available
For decades, predominant soil biogeochemical models have used conceptual soil organic matter (SOM) pools and only simulated them to a shallow depth in soil. Efforts to overcome these limitations have prompted the development of new generation SOM models, including MEMS 1.0, which represents measurable biophysical SOM fractions, over the entire root...
Article
The Forest Vegetation Simulator (FVS) growth and yield model is widely used throughout the United States, but recent studies have reported unexpectedly large bias for some regional model variants. Here we propose a general framework for model evaluation, designed to highlight model strengths and weaknesses and inform calibration efforts. We apply t...
Article
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Sustainable soil carbon sequestration practices need to be rapidly scaled up and implemented to contribute to climate change mitigation. We highlight that the major potential for carbon sequestration is in cropland soils, especially those with large yield gaps and/or large historic soil organic carbon losses. The implementation of soil carbon seque...
Article
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Biofuel and bioenergy systems are integral to most climate stabilization scenarios for displacement of transport sector fossil fuel use and for producing negative emissions via carbon capture and storage (CCS). However, the net greenhouse gas mitigation benefit of such pathways is controversial due to concerns around ecosystem carbon losses from la...
Article
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Increasing the amount of soil organic carbon (SOC) has agronomic benefits and the potential to mitigate climate change. Previous regional predictions of SOC trends under climate change often ignore or do not explicitly consider the effect of crop adaptation (i.e., changing planting dates and varieties). We used the DayCent biogeochemical model to e...
Article
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Accurate estimation of crop net primary production (NPP) and yields is fundamental for regional analyses of agroecosystem dynamics using process‐based models. In this study, we simulated croplands in the contiguous U.S. using the DayCent ecosystem model with new production algorithms. Crops were divided into crop variety groups based on regional va...
Article
Crop water production functions (quantifying crop yield as a function of irrigation rate) can help in the design of management systems that reduce the water footprint. We examined the role of parameter uncertainties in characterizing production functions using the DayCent agroecosystem model. A global sensitivity analysis was conducted to identify...
Article
Full-text available
During the last decade, China's agro-food production has increased rapidly and been accompanied by the challenge of increasing greenhouse gas (GHG) emissions and other environmental pollutants from fertilizers, pesticides, and intensive energy use. Understanding the energy use and environmental impacts of crop production will help identify environm...
Conference Paper
Full-text available
Carbon accounting at the nexus of forest management and bioenergy production has long been complex and controversial, particularly regarding whether woody feedstocks can be sustainably sourced without counter-productive reductions in forest ecosystem carbon storage. In the western U.S., recent bark beetle outbreaks have caused widespread tree morta...
Article
The adoption of more intensive and diversified pasture systems is a promising alternative to improve sustainability of grazing lands in Brazil. Phosphorus (P) is one of the main determinants of ecosystem function in these management systems; therefore, we assessed the effects of adopting more intensive and diversified pasture management systems on...
Article
Full-text available
Soil carbon (C) sequestration is one of three main approaches to carbon dioxide removal and storage through management of terrestrial ecosystems. Soil C sequestration relies of the adoption of improved management practices that increase the amount of carbon stored as soil organic matter, primarily in cropland and grazing lands. These C sequestering...
Article
Full-text available
The importance of building/maintaining soil carbon, for soil health and CO2 mitigation, is of increasing interest to a wide audience, including policymakers, NGOs and land managers. Integral to any approaches to promote carbon sequestering practices in managed soils are reliable, accurate and cost-effective means to quantify soil C stock changes an...
Article
Early thinning of loblolly pine plantations can potentially deliver sustainable feedstocks for biofuel/bioenergy. However, the management intensification for increased productivity and the removal of additional biomass from these plantations could reduce carbon (C) inputs belowground and therefore reduce overall ecosystem C storage. Increased ferti...
Article
Full-text available
Soil organic matter (SOM) dynamics in ecosystem-scale biogeochemical models have traditionally been simulated as immeasurable fluxes between conceptually defined pools. This greatly limits how empirical data can be used to improve model performance and reduce the uncertainty associated with their predictions of carbon (C) cycling. Recent advances i...
Article
We demonstrate the use of a surrogate-based optimization framework for large-scale and high-resolution landscape management optimization, using irrigated corn production systems in eastern Colorado, USA as a case study. An artificial neural network was employed to create a surrogate of the DayCent biogeochemical simulation model. Our optimization c...
Article
Biofuels have been proposed as a potential solution for climate change mitigation. However, there exist several barriers, such as "food vs fuel" issues and technological constraints, restricting the sustainable commercialization of both first-and second-generation biofuels. Combining arable crops and their residues for hybrid first-and second-gener...
Article
Full-text available
Soil organic matter (SOM) dynamics in ecosystem-scale biogeochemical models have traditionally been simulated as immeasurable fluxes between conceptually-defined pools. This greatly limits how empirical data can be used to improve model performance and reduce the uncertainty associated with their predictions of carbon (C) cycling. Recent advances i...
Article
A promising solution to help close the gap between water demand and supply in semiarid regions is deficit irrigation strategies that use less water but aim to increase crop yield per unit of water applied. Dynamic models can be used to assess the impacts of deficit irrigation and to support decision-making. In this study, we evaluated the capabilit...
Article
Agricultural land management often involves trade-offs between ecosystem services (ES) and disservices (EDS). Balancing these trade-offs to achieve low-impact production of agricultural commodities requires rigorous approaches for quantifying and optimizing ES and EDS, reconciling biophysical constraints and different management objectives. In this...
Article
A promising solution to help close the gap between water demand and supply in semiarid regions is deficit irrigation strategies that use less water but aim to increase crop yield per unit of water applied. Dynamic models can be used to assess the impacts of deficit irrigation and to support decision-making. In this study, we evaluated the capabilit...
Thesis
Full-text available
Agriculture provides many ecosystem services to human society but is also a major cause of environmental degradation. The key challenge of modern agricultural production is to meet projected increases in global demands for food, water, and energy in sustainable ways. Sustainable agricultural production requires integrated decision-support tools and...
Article
Field experimental data of maize and soybean from two locations in the US Corn Belt and winter wheat in northern Oklahoma were used to develop a modified empirical method for simulating green leaf area index (GLAI) in the DayCent model. The method is based on the change of green leaf weight ratio (GLWR) as a function of phasic development in grain...
Article
Full-text available
Although dedicated energy crops will probably be an important feedstock for future cellulosic bioenergy production, it is unknown how they can best be integrated into existing agricultural systems. Here we use the DayCent ecosystem model to simulate various scenarios for growing switchgrass in the heterogeneous landscape that surrounds a commercial...
Data
Table S1. Summary of scenarios in publications on soil N2O emissions from perennial bioenergy crops underlying Fig. 1. Table S2. Annual average (mean) N2O emissions [Mg N2O ha−1 yr−1, mean ± SE (n)] calculated for four feedstocks individually. Appendix S1. Method for calculation of net greenhouse gas (GHG) intensity for four biofuel production sc...
Article
Full-text available
United States mandated the production of biofuel from lignocellulosic feedstocks. Nonetheless, the cultivation of these feedstocks may produce debates, as agricultural land is scarce and it is primarily needed for food production and grazing. Thus, it is thought that biofuel production should be placed on land with low economical value (i.e. margin...
Article
Full-text available
Perennial bioenergy crops have significant potential to reduce greenhouse gas (GHG) emissions and contribute to climate change mitigation by substituting for fossil fuels; yet delivering significant GHG savings will require substantial land-use change, globally. Over the last decade, research has delivered improved understanding of the environmenta...
Article
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In rapidly urbanizing semi-arid regions, increasing amounts of historically irrigated cropland lies permanently fallowed due to water court policies as agricultural water rights are voluntarily being sold to growing cities. This study develops an integrative framework for assessing the effects of population growth and land use change on agricultura...
Article
In Mediterranean agroecosystems, limited information exists about possible impacts of climate change on soil N2O emissions under different land uses. This paper presents a modelling study with a dual objective. Firstly, the biogeochemical Daycent model was evaluated to predict soil N2O emissions in different land uses in a typical Mediterranean agr...
Article
Full-text available
The '4 per mille Soils for Food Security and Climate' was launched at the COP21 with an aspiration to increase global soil organic matter stocks by 4 per 1000 (or 0.4 %) per year as a compensation for the global emissions of greenhouse gases by anthropogenic sources. This paper surveyed the soil organic carbon (SOC) stock estimates and sequestratio...
Article
Cassava-based ethanol has been promoted in China and Southeast Asia as an effective means to reduce greenhouse gas (GHG) emissions and promote energy security. However, existing life cycle assessments of the environmental impacts of cassava ethanol have used highly-aggregated empirical methods to estimate ecosystem C stock changes, which do not cap...
Article
In recent years, the increase in Brazilian ethanol production has been based on expansion of sugarcane-cropped area, mainly by the land use change (LUC) pasture–sugarcane. However, second-generation (2G) cellulosic-derived ethanol supplies are likely to increase dramatically in the next years in Brazil. Both these management changes potentially aff...
Article
Full-text available
Background and aims To study the impact of land use change (LUC) from native vegetation and pasture to sugarcane cultivation as well as to evaluate the effect of different management practices on long-term SOC dynamics using the CENTURY ecosystem model. Methods A soil data set of 85 study areas including sugarcane, pasture and annual crops from el...
Chapter
Different residue management practices can affect carbon (C) allocation and thus soil C and nitrogen (N) turnover. A biogeochemical model, DAYCENT, was used to simulate the effects of bioenergy Sorghum [Sorghum bicolor (L.) Moench] residue return on soil temperature and water content, soil organic carbon (SOC), and greenhouse gas (GHG) [carbon diox...
Article
Grassland ecosystems cover a large portion of the Earths' surface and contain substantial amounts of soil organic carbon. Previous work has established that these soil carbon stocks are sensitive to management and land use changes - grazing, species composition, and mineral nutrient availability can lead to losses or gains of soil carbon. Because o...
Article
Full-text available
Agroforestry as a land management practice presents a method for partially offsetting greenhouse gas emissions from agricultural land. Of all agroforestry practices in the United States, windbreaks in particular are used throughout the United States providing a useful starting point for deriving a modelling system which could quantify the amount of...
Article
New understanding of the connection between dynamic microbial carbon use efficiency (CUE), litter decomposition products, and pathways of soil organic carbon (SOC) formation have not been fully integrated into current generalizable litter decomposition models. We developed a new approach, the Litter Decomposition and Leaching (LIDEL) model, that: 1...
Article
Full-text available
Cattle play a major role in nutrient cycling of grassland ecosystems through biomass removal and excrement deposition (urine and feces). We studied the effects of cattle excrement patches (urine at 430 and feces at 940 kg N ha-1) on nitrous oxide (N2O) and methane (CH4) fluxes using semi-static chambers on cool-season (C3), Bozoisky-select (Psathyr...
Article
In 2014, the USAID project ‘Grazing lands, livestock and climate resilient mitigation in Sub-Saharan Africa’ held two workshops, hosted by the Colorado State University, which brought together experts from around the world. Two reports resulted from these workshops, one an assessment of the state of the science, and the other an inventory of relate...
Conference Paper
Full-text available
Soils are the third largest global reservoir of carbon and the largest terrestrial ecosystem sink or source of atmospheric CO2 depending on land-use and management. The French authorities ahead of COP21 proposed the ‘four per mil’ initiative aimed at offsetting most global agricultural CO2 emissions by increasing global soil organic carbon (SOC). S...
Chapter
More than 13 Mha of nonfederal land in the southeastern U.S. are devoted to pastureland. Between 1982 and 1992, pastureland increased by 100,000 ha, with nearly 70% converted from cultivated land. We examined the potential for carbon (C) sequestration with improved pasture management and conversion into pastureland from cultivated land. Improved pa...
Article
Full-text available
Soils are integral to the function of all terrestrial ecosystems and to food and fibre production. An overlooked aspect of soils is their potential to mitigate greenhouse gas emissions. Although proven practices exist, the implementation of soil-based greenhouse gas mitigation activities are at an early stage and accurately quantifying emissions an...
Article
Full-text available
Soils are subject to varying degrees of direct or indirect human disturbance, constituting a major global change driver. Factoring out natural from direct and indirect human influence is not always straightforward, but some human activities have clear impacts. These include land use change, land management, and land degradation (erosion, compaction...
Conference Paper
Full-text available
Under the international protocols aiming at reducing the climate change impact, the land use sector is, likely, one of most complex to be accounted for greenhouse gas (GHG) emission and removal. This is related to its fragmentation and the complex biogeochemical feedbacks interacting with the human activity. Among those feedbacks, the role of erosi...