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Yushu Zhang

Bio: Yushu Zhang is an academic researcher from Rothamsted Research. The author has contributed to research in topics: Soil water & Nitrification. The author has an hindex of 7, co-authored 25 publications receiving 132 citations. Previous affiliations of Yushu Zhang include University of Melbourne & Nanjing Normal University.

Papers
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Journal ArticleDOI
TL;DR: The connection between moisture and nitrogen (N) transformation in soils is key to understanding N losses, particularly nitrate (NO3−) losses, and also provides a theoretical framework for appropriate water management in agricultural systems as discussed by the authors.
Abstract: The connection between moisture and nitrogen (N) transformation in soils is key to understanding N losses, particularly nitrate (NO3−) losses, and also provides a theoretical framework for appropriate water management in agricultural systems. Thus, we designed this study to provide a process-based background for management decision. We collected soil samples from the long-term field experiment in subtropical China, which was designed to examine tobacco and rice rotations under a subtropical monsoon climate. The field experiment was established in 2008 with four treatments: (1) no fertilization as control; (2) N, phosphorus (P), and potassium (K) fertilizers applied at recommended rates; (3) N fertilizers applied at rates 50% higher than the recommended amounts and P and K fertilizers applied at recommended rates; and (4) N, P, and K fertilizers applied at recommended rates with straw incorporated (NPKS). Soil samples were collected during the unsaturated tobacco-cropping season and saturated rice-cropping season and were incubated at 60% water holding capacity and under saturated conditions, respectively. Two 15N tracing treatments (15NH4NO3 and NH415NO3) and a numerical modeling method were used to quantify N transformations and gross N dynamics. Autotrophic nitrification was stimulated by N fertilizer both under unsaturated and saturated conditions. The rate of NO3− consumption (via immobilization and denitrification) increased under the NPKS treatment under saturated conditions. Secondly, the rates of processes associated with ammonium (NH4+) cycling, including mineralization of organic N, NH4+ immobilization, and dissimilatory NO3− reduction to NH4+, were all increased under saturated conditions relative to unsaturated conditions, except for autotrophic nitrification. Consequently, NO3−-N and NH4+-N concentrations were significantly lower under saturated conditions relative to unsaturated conditions, which resulted in reduced risks of N losses via runoff or leaching. Our results suggest that under saturated conditions, there is a soil N conservation mechanism which alleviates the potential risk of N losses by runoff or leaching.

28 citations

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TL;DR: Average N2O emission rates via autotrophic nitrification, denitrification and heterotrophicNitrification increased significantly with gross nitrification rates, NO3- contents and C:N ratios respectively, indicating that these were important factors in the N2 O production pathways for these soils.

23 citations

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TL;DR: Water-level regime alteration by reservoir operation was capable of weakening N removal from water body and lengthening internal N turnover time across redox-variable SWI, elucidate new understanding of holistic hydrological regime mechanisms on N cycling across SWI and provide insight to biogenic N nutrient management for improving the green credentials of hydroelectric reservoir.
Abstract: Water-level regime alteration-associated redox fluctuation plays a primary role in governing exchange and transformation of nitrogen (N) in water-level fluctuation zones (WLFZs), while few understanding of how hydrological regimes under reservoir operation affected N cycling across the sediment-water interface (SWI), giving rise to uncertainties in reservoir N nutrient management. Batch microcosm simulation experiments with intact sediment cores from WLFZs of the Three Gorges Reservoir (TGR) were conducted for 24 days to identify holistic flooding-drying process mechanism on N-cycling patterns. Our results showed a distinct transition of N-cycling mode across the SWI, shifting from biological denitrogen loss dominated in initial period of flooding to enhance endogenous N retention. A dramatic source-sink switch of nitrous oxide (N2O) occurred in the first 1.5 days during the flooding period. However, combined accelerating migration of NH4+-N from sediment to overlying water, and subsequently enhanced transformation of NH4+-N to NO3−-N formed from flooding to drying rotation, thereby increasing N loading to overlying water. The reason for this investigation could be attributed to intensive N loss through coupled nitrification and denitrification in oxic-anoxic microenvironments after flooding. With oxygen replenishment from atmosphere during drying phase, persistent ammonification of organic N in sediments provided sufficient source of NH4+-N for the formation of NO3−-N fraction in a more oxic overlying water. Therefore, water-level regime alteration by reservoir operation was capable of weakening N removal from water body and lengthening internal N turnover time across redox-variable SWI. These findings elucidate new understanding of holistic hydrological regime mechanisms on N cycling across SWI and provide insight to biogenic N nutrient management for improving the green credentials of hydroelectric reservoir.

20 citations

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TL;DR: In this article , the authors conducted a global assessment of soil denitrification rate, N2O/(N2O+N2) ratio, and their driving factors and mitigation strategies.

19 citations

Journal ArticleDOI
01 Mar 2019-Geoderma
TL;DR: Li et al. as mentioned in this paper examined the effect of land-use type on NO 3 − -N production and consumption pathways, in acidic soils in a subtropical region, and showed that DNRA played an important role in NO 3 -N reduction to NH 4 + -N (DNRA).

17 citations


Cited by
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01 Jan 2010

362 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarized the characteristics of gross nitrogen transformation, the fate of N fertilizer and soil N as well as the N loss pathway, and made suggestions for proper N management in the region.

129 citations

Journal ArticleDOI
TL;DR: This review critically examines both the recent advances and remaining knowledge gaps with respect to the N cycle in the vadose zone-groundwater system to support the assessment of global N stocks and management of N contamination risks.

113 citations

Journal ArticleDOI
Dinghua Peng1, Suyu Qiao1, Yao Luo1, Hang Ma1, Lei Zhang1, Siyu Hou1, Bin Wu1, Heng Xu1 
TL;DR: The results emphasized that Cd-resistant ureolytic bacteria strain CJW-1 combined with OS had excellent ability and reuse value to remediate C d-contaminated environment.

81 citations