Nitrogen source track and associated isotopic dynamic characteristic in a complex ecosystem: A case study of a subtropical watershed, China

Hao, Zhipeng; Zhang, Xinyu; Gao, Yang; Xu, Zhiwei; Yang, Fengting; Wen, Xuefa; Wang, Yueming

doi:10.1016/j.envpol.2018.01.078

Cited by 22 publications

(3 citation statements)

References 43 publications

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“…The fraction of δ 18 O in soil solutions intercepted by vegetation canopy derived from enriched water, whereas the other fractions derived from rainfall and canopy interception. Therefore, the fraction of N and its isotopic flow rates from soil solutions to baseflow under the different land use types under rainfall infiltration is an important pathway for N distribution in subtropical watersheds (Cheng & Liu, ; Hao et al, ; Mathieu & Bariac, ).…”

Section: Discussionmentioning

confidence: 99%

Tracking the fate of deposited nitrogen and its redistribution in a subtropical watershed in China

et al. 2019

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Vegetation cover and soil infiltration can result in nitrogen (N) redistribution and associative isotopic fractionation. This study investigated N and its isotopic characteristics from deposition to baseflow under different vegetation canopy cover types in a subtropical watershed in China. Results showed that canopy interception via vegetation cover types exhibited notable dilution effects on reactive nitrogen (Nr) deposition during the rainy season, with the highest maximum value of 287.4%. The range of δ15N changed from 3.0‰ to 11.9‰ in throughfall, which may have resulted from an increase in N taken up by vegetation and particles washed away from plant leaves during rainfall events. Throughfall, soil water, precipitation, and rainfall run‐off were the sources of D and 18O‐H2O in baseflow river water, wherein the rainwater and rainfall run‐off contributed 73% ± 8% and 15% ± 12%, respectively. Soil water was the main source of 15N‐NO3 in baseflow river water, which contributes 78% ± 4% of overall source, but precipitation only contributes 10%. The average annual Nr deposition flux was 24.4 ± 4.2 kg·ha−1·yr−1, whereas the annual total nitrogen exportation flux was 1062 ± 269.8 kg·yr−1. The 46% of HDO or D2O for river water came from rainfall run‐off, which would transport a maximum nitrate flux of 354 kg·yr−1. Moreover, vegetation cover and soil infiltration resulted in δ15N enrichment and a decrease in Nr in river flow.

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Section: Discussionmentioning

confidence: 99%

Tracking the fate of deposited nitrogen and its redistribution in a subtropical watershed in China

et al. 2019

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“…China's "14th Five-Year Plan", a road map for the nation's development from 2021-2025, still focuses on strengthening the protection and utilization of agricultural resources, the prevention and control of agricultural non-point-source pollution, the protection and restoration of agricultural ecology, and building a green and low-carbon agricultural industrial chain. Manure is one of the main sources of N and P runoff losses [19], and organic farming systems still have eutrophication potential and acidification potential. N and P runoff losses are influenced by several factors, such as soil, climate (rainfall regimes) [10], and agricultural practices [20].…”

Section: Introductionmentioning

confidence: 99%

Effects of Organic Fertilization Rates on Surface Water Nitrogen and Phosphorus Concentrations in Paddy Fields

Liu

Huang

et al. 2022

Agriculture

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Inappropriate organic fertilizer application may cause serious environmental risks, especially nitrogen (N) and phosphorus (P) losses. To achieve a win–win for high yield and environmental protection in organic agriculture, it was essential to demonstrate the relationship between the organic fertilizer input, rice yields, and risks of N and P losses. Based on a rice and green manure cropping rotation field experiment in the Yangtze River Delta of China, the effects of organic fertilization rates on the dynamics of surface water N and P concentrations and rice grain yields were determined. The results showed that the N (total N, ammonium-nitrogen, nitrate-nitrogen) and P (total P and dissolved P) concentrations in surface water immediately and greatly reached the highest values 1 day after basal fertilization and topdressing fertilization. Then, the N and P concentrations sharply decreased and were maintained at a relatively low level. The initial 3 and 7 days after organic fertilization were the high-risk periods for controlling N and P runoff losses. The surface water N and P concentrations had a positive correlation with the organic fertilization rate in high-risk periods. Besides, the effects of organic fertilization on surface water P concentrations existed longer than those of N concentrations. The rice grain yields increased with the increase in organic fertilization rates, but high organic fertilizer input (>225 kg N per hectare) did not increase the grain yield. Meanwhile, the high organic fertilizer input had the highest risks for N and P losses. Therefore, in organic rice farming, organic fertilization rates with 150~200 kg N per hectare are the optimal organic fertilizer input, with relatively high grain yields and low N and P losses.

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“…The use of chemical fertilizers, particularly for water-soluble urea, has contributed significantly to agriculture while giving rise to negative effects such as soil pollution, eutrophication of water bodies, and air pollution. − This has led to a gradual increase in the use of slow-release fertilizers (SRFs). − Among the various SRFs, coated SRFs have a good slow-release effect and a nutrient-release cycle that is more appropriate with the absorption of plants. , Therefore, the use of coated SRFs improves the fertilizer efficiency and reduces the amount of fertilizer that needs to be used, , leading to intense interest in SRFs in agriculture research. Coating with water-blocking materials is a common method for the preparation of traditional coated SRFs, in which a film layer is wrapped on the surface of a rapidly acting fertilizer (such as urea).…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Flowable Poly(lactic acid)/Polycaprolactone Blends for the Solvent-Free Preparation of Slow-Released Urea Fertilizer in a Thermal Shear Field

Xia

Zhang

Yang

et al. 2020

Ind. Eng. Chem. Res.

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This work reports a convenient and large-scale method for the preparation of slow-release urea by melt coating with modified poly(lactic acid) (PLA)/polycaprolactone blends at low temperatures. The simple process is environmentally friendly and solvent-free, which can realize the industrial production of coated fertilizers. After being modified by ferric chloride, the crystallinity and molecular weight of poly(lactic acid) (PLA) are greatly reduced and the melt fluidity of PLA is improved. The lowest melting flowable temperatures of the PLA-modified blend was decreased to 115 °C, enabling the melt coating of urea particles using a mechanical stirrer. Because of the good compatibility of PLA with urea, a complete coating layer was formed on the surface of the urea particles by simple mixing at 120 °C, and the change of coating content has a great impact on the release effect. For the slow-release urea melt-coated with 18 phr of the blend, the time of the maximum release rate was delayed significantly and the cumulative release rate was 80.63% after 28 days in soil column leaching. When the coated granular slow-release urea was hot-pressed into a large cylinder, the slow-release effect was further enhanced. Simultaneously, with the massive use of PLA, its waste disposal becomes especially important, preparation of slow-release urea by melt-coating in this environmentally friendly manner needs to adjust the molecular weight and crystallinity of PLA, and its performance requirements are low. The work in this paper may provide a new approach for the recycling and reuse of waste PLA.

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Nitrogen source track and associated isotopic dynamic characteristic in a complex ecosystem: A case study of a subtropical watershed, China

Cited by 22 publications

References 43 publications

Tracking the fate of deposited nitrogen and its redistribution in a subtropical watershed in China

Tracking the fate of deposited nitrogen and its redistribution in a subtropical watershed in China

Effects of Organic Fertilization Rates on Surface Water Nitrogen and Phosphorus Concentrations in Paddy Fields

Low-Temperature Flowable Poly(lactic acid)/Polycaprolactone Blends for the Solvent-Free Preparation of Slow-Released Urea Fertilizer in a Thermal Shear Field

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