Jian Liu
Research Scientist
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I am a soil scientist working on agricultural effects on the environment and crop production. By combining experimentation, modeling and data synthesis approaches and collaborating with scientists, students and stakeholders in a wide range of areas, I study agricultural nutrient and water quality management at various spatial and temporal scales, and extend my research to soil health, crop production, greenhouse gas emissions and generally sustainable agriculture.
My research and collaboration interests include:
- Agricultural impacts on the environment
- Water and nutrient leaching and runoff, and soil erosion
- Gas emissions
- Field and watershed monitoring and modeling
- Soil fertility and health
- Nutrient cycling
- Crop production
- Best management practice assessment and implementation
- 4R nutrient stewardship (fertilizers, manure and soil nutrients)
- Soil (tillage, and biochar and other amendments), crop (crop rotation, catch crop and crop residue), water and livestock management
- Other general areas
- Climate impact mitigation and adaptation
- Sustainable agriculture
- International collaborations
I obtained my Ph.D. in soil science with a focus on phosphorus and water quality management from the Swedish University of Agricultural Sciences (SLU) in Uppsala, Sweden. Before joining NIBIO, I had conducted research at SLU, and in China (Northwest Agricultural and Forestry University, and Chinese Academy of Agricultural Sciences), United States (Pennsylvania State University, and U.S. Department of Agriculture – Agricultural Research Service), and Canada (University of Saskatchewan, and University of Manitoba).
Selected awards:
- Water Security Research Excellence Award, University of Saskatchewan, 2022.
- Outstanding Associate Editor Award, Journal of Environmental Quality, 2021.
- Outstanding Associate Editor Award, Journal of Environmental Quality, 2020.
- 2nd Prize for Outstanding Scientific Papers (Agricultural & Forestry Subject), Chinese Association for Science and Technology, 2017.
Abstract
Quantifying the similarities and differences in atmospheric nitrogen (N) deposition between different ecosystems is important to develop effective measures to reduce air pollution and maintain biodiversity. Here we show that the constitution of N deposition differed significantly between a grassland and a desert ecosystem in Northwestern China. Flux of bulk (wet plus part of dry deposition) and dry (gaseous NH3 and NO2) deposition were continuously monitored from 2018 to 2020. The grassland and desert sites had similar amount of total N deposition, being 7.29 and 6.33 kg N ha−1 yr−1, respectively. However, N deposition at the grassland was dominated by the bulk deposition (4.44 kg N ha−1 yr−1, 61% of the total N deposition), whereas that at the desert was dominated by dry deposition (4.20 kg N ha−1 yr−1, 66% of total deposition). The desert had greater ambient concentrations of NH3 (3.66 μg N m−3) and NO2 (1.52 μg N m−3) than the grassland (2.73 μg NH3–N m−3 and 0.72 μg NO2–N m−3). The amount of reduced N deposition (NH4+ and NH3) was around 3 times of that of oxidized N deposition (NO3− and NO2) in both ecosystems. The N deposition rates in both ecosystems have exceeded the critical load for the fragile ecosystems (5–10 kg N ha−1 yr−1), highlighting the importance of reducing N emission sources that are related with anthropogenic disturbance.
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Authors
Fang-di CHANG Xi-quan WANG Jia-shen SONG Hong-yuan ZHANG Ru YU Jing WANG Jian Liu Shang WANG Hong-jie JI Yu-yi LIAbstract
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Abstract
Soil nutrient contents and stoichiometric ratios are determinants for soil biogeochemical cycling and functions. Variable rock fragment contents (RFC) may shape the soil nutrient status and availability in mountain ecosystems. We need to better understand how and why soil nutrients and stoichiometry shift across the RFC gradients. To investigate patterns of soil nutrient stoichiometry and underlying mechanisms in rocky soils, we conducted a field experiment involving four RFCs gradients (0%, 25%, 50% and 75%, V/V) and five vegetation treatments (four indigenous species, Artemisia vestita, Bauhinia brachycarpa, Cotinus szechuanensis and Sophora davidii, plus a non-planted treatment). Soil total carbon (C), total nitrogen (N), total phosphorus (P) and their molar ratios were measured. The contents of soil C, N and P, and C:N, C:P and N:P decreased with increasing RFC in all treatments, despite their trends were inconsistent in certain soil layers. The averages of soil N content significantly increased by 13.8% and 14.8% in C. szechuanensis and S. davidii, respectively. A. vestita and B. brachycarpa had higher soil C:N than C. szechuanensis and S. davidii. Soil nutrients and stoichiometry were positively related to soil water content (SWC) and soil capillary porosity, and negatively to bulk density and soil non-capillary porosity in all vegetation treatments, but varying relationships with biomass of plant components. These results demonstrated negative effect of RFC and discrepant effects of the plants on soil nutrients and stoichiometry. Soil structure, SWC and vegetation were the main drivers of variations in soil nutrient stoichiometry. We further concluded that soil nutrient stoichiometry in rocky soils is shaped by two influencing paths; effects of RFC on soil physical properties (SWC and soil structure) and effects of different vegetations. Our findings advance knowledge and mechanisms of soil nutrient stoichiometry in rocky soils and provide theoretical support for improving and restoring nutrient status in stony regions.
Authors
Ji Liu Yi Wang Yong Li Josep Peñuelas Ying Zhao Jordi Sardans Doerthe Tetzlaff Jian Liu Xinliang Liu Hongzhao Yuan Yanyan Li Ji Chen Jinshui WuAbstract
Whether and how to synchronously regulate stream water nitrogen (N) and phosphorus (P) concentrations and ratios is a major challenge for sustainable aquatic functions. Soil carbon (C):N:P ratios influence soil N and P stocks and biogeochemical processes that elicit subsequent substantial impacts on stream water N and P concentrations and ratios. Therefore, bridging soil and stream water with ecological stoichiometry is one of the most promising technologies for improving stream water quality. Here, we quantified the ecological stoichiometry of soil and stream water relationships across nine catchments. Soil C:P ratio was the main driver of water quality, showing negative correlations with stream water N and P concentrations, and positive correlations with the N:P ratio in P-limited catchments. We revealed that soil C:P ratios higher than 97.8 mol mol−1 are required to achieve the simultaneous regulation of stream water N and P concentrations below the eutrophication threshold and make algal growth P-limited. Furthermore, we found that the relationships between catchment landscape and soil ecological stoichiometry likely provided practical options for regulating soil ecological stoichiometry. Our work highlights that soil ecological stoichiometry can effectively indicate the amount and proportion of soil N and P losses, and can be intervened through rational landscape planning to achieve sustainable aquatic ecosystems in catchments.
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Authors
Jian LiuAbstract
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Abstract
We conducted a study over four rice seasons to assess the effects of dairy manure application on water loss, nutrient leaching, and rice yield compared to chemical fertilization. Water input, soil water storage, water percolation, plant growth, and yield data were recorded under triplicate field lysimeters that received either chemical fertilizers or organic manure. The lysimeters received alternate wetting and drying irrigation (5-cm after 3 days (2018 Aman season), 6 days (2019 Boro and Aman seasons), and 9 days (2020 Boro season) of ponded water disappearance) in addition to rainfall (37.5, 33.1, 40.9, and 47.4 cm, respectively). Leachate and ponded water samples were analyzed for nitrogen (N) species (NH+4 - N and NO−3 - N) and available phosphorus (P) content. Manure application increased soil water storage by 1.2–4.4 cm/m but did not affect percolation loss (44–64% of water input) in silt loam soil. The chemical fertilization had significantly higher leaching concentrations of nutrients (NO−3 - N at 0.75–3.6 mg/L and P at 0.02–0.15 mg/L) in several leaching events in the last three seasons than the manure treatment (NO−3 - N at 0.75–3.2 mg/L and P at 0–0.21 mg/L). Overall, the manure treatment reduced the leaching load of N and available P by 13% and 23.6%, respectively. The N and P concentrations in the topsoil were higher for the manure treatment. Manure application increased rice yield by 15% and water productivity by 0.07 kg/m3 by augmenting soil water availability during the drying cycles of alternate wetting and drying processes. In addition, recycling manure in soil significantly reduced its environmental pollution compared to other inappropriate disposal methods. However, research needs remain important to adjust manure management options.
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Authors
Jian LiuAbstract
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Abstract
Aims Root traits associated with resource foraging, including fine-root branching intensity, root hair, and mycorrhiza, may change in soils that vary in rock fragment content (RFC), while how these traits covary at the level of individual root branching order is largely unknown. Methods We subjected two xerophytic species, Artemisia vestita (subshrub) and Bauhinia brachycarpa (shrub), to increasing RFC gradients (0%, 25%, 50%, and 75%, v v− 1) in an arid environment and measured fine-root traits related to resource foraging. Results Root hair density and mycorrhizal colonization of both species decreased with increasing root order, but increased in third- or fourth-order roots at high RFCs (50% or 75%) compared to low RFCs. The two species tend to produce more root hairs than mycorrhizas under the high RFCs. For both species, root hair density and mycorrhizal colonization intensity were negatively correlated with root length and root diameter across root order and RFCs. Rockiness reduced root branching intensity in both species comparing with rock-free soil. At the same level of RFC, A. vestita had thicker roots and lower branching intensity than B. brachycarpa and tended to produce more root hairs. Conclusion Our results suggest the high RFC soil conditions stimulated greater foraging functions in higher root orders. We found evidence for a greater investment in root hairs and mycorrhizal symbioses as opposed to building an extensive root system in rocky soils. The two species studied, A. vestita and B. brachycarpa, took different approaches to foraging in the rocky soil through distinctive trait syndromes of fine-root components.
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Division of Food Production and Society
ECONUTRI
Innovative concepts and technologies for ECOlogically sustainable NUTRIent management in agriculture aiming to prevent, mitigate and eliminate pollution in soils, water and air
Division of Food Production and Society
Agricultural mitigation measures and the value of water quality improvements
Agriculture is one of the main sources of water pollution in Norway, and an important contributor to GHG emissions.